Patent Publication Number: US-2018044918-A1

Title: Pre-fabricated structures and methods

Description:
The present application is a continuation-in-part of application Ser. No. 14/819,419, filed on Aug. 5, 2015, now U.S. Pat. No. 9,797,135, which claims priority from U.S. Provisional Patent Application Ser. No. 62/033,115, filed on Aug. 5, 2014 entitled: “Pre fabricated structures and methods” which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Portable structures have been used by people, including soft walls structures such as tents and teepee and portable building having rigid or semi-rigid walls. Some portable buildings can be transported assembled, e.g., the structure is complete and transported by truck or rail to the site. Some portable buildings can be transported in components, e.g., the complete structure is disassembled and transported as components to be assembled at the site. 
     There is a need for construction designs that can use available and inexpensive materials, together with ease of fabrication, construction, and assembling. 
     SUMMARY OF THE EMBODIMENTS 
     In some embodiments, the present invention discloses pre-fabricated houses and methods to construct pre-fabricated houses. The pre-fabricated houses can include beams, such as vertical pillars and horizontal joists, together with wall panels. 
     In some embodiments, the present invention discloses pillars and wall panels having attachments or mating components for ease of construction. The attachments or mating components can include a metal material for ease of coupling, such as welding or bolting, e.g., securing with nuts and bolts. 
     In some embodiments, the pillars can include a metal material, such as the pillars are made from steel. The attachments can be fabricated from the pillars, for example, the attachments can include a component from the pillars, or a hole in the pillars for coupling with a foundation of the house or for coupling with a wall panel. The attachments can be a part of the pillars, e.g., the hole can be made in the pillars, or the component can be a portion of the pillars. 
     In some embodiments, the pillars can include a cement material, such as the pillars are made from concrete, e.g., a mixture of cement, sand and water. The concrete pillars can have metal-based attachments, e.g., attachments having a metal material such as steel. The metal-based attachments can be secured to the concrete, or can be secured to a metal-based reinforced element in the concrete. 
     In some embodiments, the wall panels can include metal-based attachments, e.g., attachments having a metal material such as steel. The metal-based attachments can be secured to the wall panels. The attachments can be configured to se coupled to the pillars or to the attachments of the pillars, for example, by welding or bolting. 
     In some embodiments, the wall panels can include a cement material, e.g., forming a concrete wall panel. The wall panels can have metal-based attachments secured to the cement material. The metal-based attachments can facilitate the coupling of the wall panels with other wall panels or with beams (vertical pillars or horizontal joists), e.g., through the coupling of metal to metal. 
     In some embodiments, the present invention discloses methods for constructing pre-fabricated houses. The methods can include forming a foundation for a house. The foundation can have metal-based attachments, which can be configured to be coupled to the pillars of the house. The methods can include coupling multiple beams to the foundation. The beams can include metal-based attachments, which can be configured to be coupled to the foundation. The beams can include other metal-based attachments, which can be configured to be coupled to the wall panels. The methods can include coupling the wall panels to the beams. The wall panels can include metal-based attachments, which can be configured to be coupled to the beams. In some embodiments, the wall panels can be concrete wall panels, e.g., wall panels having a cement material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-1B  illustrate a portable house according to some embodiments. 
         FIGS. 2A-2E  illustrate pillars and wall panels according to some embodiments. 
         FIG. 3  illustrates a flow chart for forming components of a house according to some embodiments. 
         FIGS. 4A-4E  illustrate configuration for concrete wall panels according to some embodiments. 
         FIGS. 5A-5E  illustrate configurations for wall panels having meshes according to some embodiments. 
         FIGS. 6A-6E  illustrate configurations for end portions of wall panels according to some embodiments. 
         FIGS. 7A-7D  illustrate configurations of attachments for wall panels according to some embodiments. 
         FIGS. 8A-8F  illustrate configurations of attachments for wall panels according to some embodiments. 
         FIGS. 9A-9F  illustrate configurations of attachments for wall panels according to some embodiments. 
         FIG. 10  illustrates a wall panel according to some embodiments. 
         FIG. 11  illustrates a flow chart for fabricating a concrete wall panel according to some embodiments. 
         FIGS. 12A-12E  illustrate configurations for assembling wall panels according to some embodiments. 
         FIG. 13  illustrates a flow chart for assembling wall panels according to some embodiments. 
         FIGS. 14A-14G  illustrate configurations for assembling a wall panel with a beam according to some embodiments. 
         FIG. 15  illustrates a flow chart for assembling wall panels according to some embodiments. 
         FIGS. 17A-17F  illustrate configurations for assembling pre-fabricated houses according to some embodiments. 
         FIGS. 16A-16G  illustrate configurations for assembling pre-fabricated houses according to some embodiments. 
         FIG. 18  illustrates a flow chart for assembling wall panels according to some embodiments. 
         FIGS. 19A-19D  illustrate various configurations for assembling pre-fabricated houses according to some embodiments. 
         FIGS. 20A-20C  illustrate various configurations for assembling pre-fabricated houses according to some embodiments. 
         FIG. 21  illustrates a configuration for assembling pre-fabricated houses according to some embodiments. 
         FIGS. 22A-22C  illustrate a process for constructing a house according to some embodiments. 
         FIG. 23  illustrates a configuration of wall panel and pillar attachments according to some embodiments. 
         FIGS. 24A-24B  illustrate a process for forming a two story house according to some embodiments. 
         FIG. 25  illustrates a flow chart for constructing a pre-fabricated house according to some embodiments. 
         FIGS. 26A-26G  illustrate wall panels according to some embodiments. 
         FIGS. 27A-27C  illustrate a process for alignment improvement according to some embodiments. 
         FIG. 28  illustrates a flow chart for alignment improvement according to some embodiments. 
         FIGS. 29A-29B  illustrate a process for installing wall panels according to some embodiments. 
         FIGS. 30A-30B  illustrate a process for installing wall panels according to some embodiments. 
         FIG. 31  illustrates a flow chart for constructing a portable house according to some embodiments. 
         FIGS. 32A-32F  illustrate a process for assembling a prefab house according to some embodiments. 
         FIG. 33  illustrates a coupling configuration between a floor or ceiling panel  3310  with a wall panel or the beams  3320 . 
         FIGS. 34A-34G  illustrate coupling configurations between wall panels according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In some embodiments, the present invention discloses portable houses and methods to fabricate portable houses. The portable houses can be transported in a vehicle such as a truck to a construction site, and then assembled at the construction site. The term houses can include any dwelling structures, e.g., buildings for living, storage structures, e.g., buildings for storing, or office buildings, e.g., buildings for working. The term portable can include movable, such as moving by components and then assembling at the construction site. 
     The portable houses can include wall panels, beams such as vertical pillars or horizontal joists, floor panels and roof panels. A foundation can be built at the construction site, then the floor panels can be installed. Pillars can be attached to the floor panels, such as at 4 corners of the floor panels. Alternatively, the pillars can be attached to the foundation before the installation of the floor panel. The wall panels can be attached to the beams or pillars. The roof panels, or second floor panels, can be attached to the beams or pillars and/or to the wall panels. Optional components can be included, such as floor support members, truss members, and upright studs. 
       FIGS. 1A-1B  illustrate a portable house according to some embodiments. In  FIG. 1A , multiple panels  110 , such as floor panels, wall panels, and roof panels can be transported to a building site. The panels can have different sizes, pre-fabricated according to the design of the house. Windows and doors can also be prefabricated on the panels, such as sky doors on roof panels, basement door on floor panels, and doors and windows on wall panels. Electrical components, such as wall outlets or wall connectors for lighting or for internet cables, can be prefabricated on the wall panels or ceiling panels. Other components can be included, such as pillars and support structures. The components can include attachments, for example, to couple or attach to other components. 
     Support structures can be included either as a separate component or a component pre-attached to the panels, beams, or pillars. For example, rim joists can be coupled to bottom of the wall panels, upright posts or studs can be embedded in wall panels, for example, to increase the structural integrity of the wall panels, floor joints and floor support members can be embedded in floor panels to increase the structural integrity, rafters can be embedded in roof panels, and fasteners for securing the panels together. 
     In  FIG. 1B , the panels  110  can be assembled to form a complete house. In some embodiments, the wall panels  120  can be fabricated and transported as complete wall panels, e.g., large wall panels that can be used to form the house walls with one or two wall panels. The wall panels  120  can have multiple wall pieces  122 ,  124 , and  126  assembled together, with the separation between the wall pieces along a direction  130  of the vertical pillars. The wall pieces can be one large piece, from a ceiling  140  to a floor  145  of the house. 
     In some embodiments, the present invention discloses pre-fabricated housing and methods to construct pre-fabricated housing. The pre-fabricated houses, e.g., structures for dwelling or for storing, can include major support vertical pillars, such as pillars at four corners of the houses (for example, for houses having dimensions of 5 m×5 m or less, or for houses having lateral wall dimensions of 5 m or less), and middle pillars (for example, for houses having dimensions larger than, or for houses having lateral wall dimensions greater than 5 m, such as a middle pillar for 5 m×10 m houses at the middle of the 10 m walls). The pre-fabricated houses can include large panels, such as complete wall panels, roof panels, or floor panels, such as complete panels between the pillars. For example, a 5 m×5 m house can have 4 pillars at four corners of the house, together with 4 wall panels having 5 m lateral dimensions. A 5 m×10 m house can have 6 pillars, 4 at four corners and 2 at the middles of the 10 m length of the house, together with 6 wall panels having 5 m lateral dimensions. 
     The pillars and complete wall panels can simplify the construction of the houses, since after forming a foundation of the house at the construction site, a minimum number of floor panels, roof panels, walls panels, and pillars can be transported to the construction site for assembling. 
     In some embodiments, the pillars can be made of a metal material, e.g., an metal alloy such as steel. The wall panels can be made of a cement material, e.g., a large piece of cement can be formed as a wall panel. Steel reinforced mesh can be included in the cement-based wall panels, for example, to increase the structure integrity of the cement-based wall panels. Other elements can be incorporated in the fabrication of the large cement wall panels, such as openings for electrical components, metal-based attachments for coupling with the metal-based beams such as vertical pillars or horizontal joists. The wall panels can have hollow pockets for weight reduction, such as hollow passages from one end to an opposite end of the wall panels. The hollow passages can be horizontal passages, vertical passages, or a combination of horizontal and vertical passages. 
     In some embodiments, the present invention discloses pillars and wall panels having mating components for ease of construction. The pillars, wall panels, and mating components can include available, low cost elements such as C shape or L shape beams. 
       FIGS. 2A-2E  illustrate pillars and wall panels according to some embodiments. In  FIG. 2A , a pillar  210  can include 2 C shape beams  212  and  214  secured together, for example, by welding  220  or by nuts and bolts. For example, a C shape beam can have a first width  214 A of 12 cm, a second width  214 B of 4.8 cm, and a thickness  214 C of 0.6 cm. The pillar  210  can also include a bottom and a top flanges for securing to the bottom panels (such as floor panels) and to the top panels (such as a top floor or a roof). Other dimensions can also be used. 
     The two C shape beams  212  and  214  can be welded back to back, with an offset amount, for example, about half the first width  214 A of the C shape beam. Holes can be drilled into C shape beams for attaching with nuts and bolts. Alternatively, nuts or bolts can be welded to the C shape beams. 
     In  FIG. 2B , a panel, such as a wall panel  230 , can include a wall  250  having end beams  260 ,  262  and attachments  240 ,  242  at two end of the wall  250 . The wall  250  can be constructed of cement, or some light weight materials. A solid wall  250  is shown, but other configurations can be used, such as two thin walls at outer surfaces. 
     At the ends of the walls  250 , end beams  260  and  262  can be attached. The end beams can surround the wall, e.g., at 4 end sides of a rectangular wall. The end beams can be attached to 2 opposite end sides of the wall. The end beams can include C shape beams. Attachment beams  240  and  242  can be coupled to the end beams  260  and  262  respectively. The attachment beams can include L shape beams. Holes can be drilled into L shape beams for attaching with nuts and bolts. Alternatively, nuts or bolts can be welded to the L shape beams. The holes, nuts, and bolts in the L shape beams of the wall panels can be mated to the holes, nuts and bolts in the C shape beams of the pillars. The L shape beams  240  and  242  can be attached so that the flat side  270  can be at a center line of the wall panel  230 . This can allow the wall panel to couple to another beam (such as the pillar) with a center disposed between the two beams. The two L shape beams  240  and  242  can be disposed at opposite sides. 
     In some embodiments, the wall  250  can include a cement material, for example, to form a concrete wall. In addition, cement additives can be included, to modify the properties of the concrete wall. For example, a latex resin, such as Polyvinyl Acetate (PVA), Ethylene Vinyl Acetate (EVA), Styrene Butadiene Rubber (SBR), and Acrylic, can be used for increasing the compressive strength (such as tensile, flexural, compression, and modulus), reducing the weight, reducing water permeability and absorption, increasing abrasion resistance, dampening vibration, color retention, and resistance to aggressive and corrosive environments such as rain water, freeze-thaw cycles, or seawater. The concrete can be impregnated with a liquid monomer that is polymerized in situ. Additives can also include plastic materials, such as thermoset polyester, phenolic, epoxy, and poly ethylene. 
     The concrete, e.g., the wall having a cement material, can be a lightweight concrete, which can include an additive for reducing the weight of the concrete. The additives can include a foam additive, which can generate bubbles in the concrete, forming porous concrete. 
     In  FIG. 2C , the L shape beams  244  and  246  can be attached at a different configuration as compared to the L shape beams  240  and  242  in  FIG. 2B . For example, the two L shape beams  244  and  246  can be disposed at a same side. 
     In  FIG. 2D , a side view of the panel  235  is shown. The wall panel  250  can be surrounded at all sides by end beams  260 ,  262 ,  264 , and  266 . The end beams  260  and  262  can have attachment beams  240  and  242 , which are configured to be attached to pillars, e.g., C shape beams of the pillar. The end beams  264  and  266  can be configured to be attached to the bottom and/or top floor panels. 
       FIG. 2E  shows another configuration of a wall panel  237 . End beams  260  (and  262 ,  264 ,  266  as shown in  FIG. 2D ) can be secured together, e.g., by welding, to form a frame. Middle beams  252  can be attached to the frame to increase the structural integrity. Thin walls  258  can be attached to the frame to form the wall panel  237 . The thin wall  258  can have a plastic-concrete composition, e.g., concrete having a plastic additive (such as a latex additive such as acrylic resisn), for example, to increase compressive strength for forming thin wall. 
       FIG. 3  illustrates a flow chart for forming components of a house according to some embodiments. Operation  300  attaches two first C-shape beams to form a pillar. The first C-shape beams can be attached back to back with an offset. The side portions of the C shape beams can be used as attachment points for the wall panels. The two C shape beams thus can include 4 side portions, two at one side, and two at the opposite side. The side portions can be offset, e.g., positioned at different planes. 
     Operation  310  forms a wall panel having one or more second C shape beams as frame. For example, a wall panel can be provided, and C shape beams can be attached to two edge sides or to 4 edge sides of the wall panel. Alternatively, two or four C shape beams can be coupled together, for example, by welding or by bolting, for form a frame. Additional beams can be used, for example, as middle beams or as edge beams (in the case of 2 C shape beam frame). The additional beams can be smaller, lighter, or can be of different materials. Wall plates can be coupled to the frame, for example, at both flat sides of the frame, to form a wall panel. 
     Operation  320  attaches a L-shape beam to a second C-shape beam. Two L shape beams can be used, attached to two opposite C shape beam of the wall panel. The L shape beam can be formed after forming the frame, and before attaching the wall plates. The L shape beams can be formed after forming the wall panel. 
     Operation  330  transports the pillars and the wall panels to a construction site. Operation  340  couples the wall panels to the pillars to form a pre-fabricated house. A foundation can be first constructed at the construction site. A floor can be formed on the foundation. The floor can include one or more floor panels, depending on the size of the house. For example, the floor panels can have dimensions of 5 m or less. The floor panels can include attaching components for attaching the pillars. For example, the floor panels can have protruded bolts at corners and/or middles of edges of the floor panels, which can be used to attach to the pillar, since the pillars can have mated holes at the ends. 
     The pillars can be coupled to the floor panels, for example, by bolting the pillars to the protruded bolts from the floor panels. Alternatively, the floor panels can have metal plates at corners and the pillars can be welded to the metal plates. Afterward, the wall panels can be coupled to the pillars, for example, by bolting or welding the pillars with the end beams of the wall panels. For one story houses, roof panels can be attached to the pillars. For two or more story houses, upper floor panels can be attached to the pillars. 
     In some embodiments, the present invention discloses cement-based wall panels for a pre-fabricated house. The cement-based wall panels can include a cement material. For example, the cement-based wall panels can include concrete, which is a harden mixture of cement, sand, and water, together with optional gravels or crushed stones. The wall panels can be large, such as having a length from the ceiling to the floor, e.g., the wall panels form one piece wall along a vertical direction of the house. The width of the wall panels can be from a pillar to another pillar, or can be a fraction of the pillar-to-pillar distance. For example, the width of the wall panels can be 1.2 m, thus multiple wall panels (or wall pieces) can be put together side by side to form a complete wall panel. 
     In some embodiments, the thickness of the wall panels can be larger than 10 mm, such as larger than 100 mm, or larger than 200 mm. The wall panels can be hollow, e.g., having hollow pockets such as hollow passages from one end of the panel to an opposite end. The hollow passages can lighten the wall panels, and at a same time, allowing electrical wires to pass through the wall panels. 
     In some embodiments, the cement-based wall panels can have additives for changing the properties of the concrete wall panels. For example, a plastic additive can be added to the cement mixture to increase the compressive strength of the concrete, allowing the formation of thin wall concrete. The plastic additives can include a latex resin, such as an acrylic resin. Other additives can be included, such as foam additives, which can form air bubbles in the concrete, for forming lightweight concrete. 
     In some embodiments, the wall panels can have attachments for coupling to other components of the house, such as coupling to the beams (e.g., vertical pillars or horizontal joists) or to each other. The attachments can include a metal material, such as the attachment can be made of metals or alloys such as steel or iron-based alloys. Metal-based attachments can simplify coupling, for example, by welding or by bolting with bolts and nuts. Thus the wall panels and beams can have metal-based attachments. 
     In some embodiments, the metal-based attachments can be bonded to concrete, e.g., the cement-based wall panels. An interlocked feature can be included to secure the attachment to the concrete. 
     In some embodiments, the wall panels can have a step at an end of the wall panels. The step can simplify the coupling of the wall panels, e.g., to a pillar or to another wall panel. Metal-based attachments can be coupled to the step. 
     In some embodiments, the present invention discloses a pre-fabricated house using one-piece vertical concrete wall panels. The one-piece vertical concrete wall panels can have a length similar to a height of the house, such as a distance from the floor to the ceiling. Multiple one-piece vertical wall panels can be assembled together, along the length, to form a complete wall panel. The coupling of the one-piece vertical wall panels can be through the metal-based attachments, e.g., by welding or bolting. 
     In some embodiments, the pre-fabricated house can include metal-based beams, such as vertical pillars and/or horizontal joists. The beams can include steel or other iron-based alloys. The beams can be fabricated with attachments for coupling directly with the wall panels or with the metal-based attachments of the wall panels. The attachments can be formed from the beams, e.g., holes can be drilled in the beams to form the attachments. The attachments can be externally formed, and then coupled to the beams, e.g., a protrusion with a hole can be welded to the beams to form the attachment. 
     In some embodiments, the pre-fabricated house can include cement-based or concrete-based beams, such as vertical pillars. The beams can be fabricated with metal-based attachments for coupling directly with the wall panels or with the metal-based attachments of the wall panels. The attachments can be coupled to the cement or concrete portion of the beams, optionally with interlocked feature for securing the attachments to the concrete or cement beams. The attachments can be coupled to a metal-based reinforced portion of the beams, for example, by welding or bolting. 
       FIGS. 4A-4E  illustrate configuration for concrete wall panels according to some embodiments. The concrete wall panels can include a cement material, for example, a mixture of cement, sand, water, and other optional elements. The concrete wall panels can be porous, e.g., having hollow void inside the wall panels, for example, to reduce the weight of the wall panels. 
     In  FIG. 4A , a concrete wall panel  400  can include a concrete material  410 , e.g., a mixture of a cement material with other elements, together with hollow passages  420 . The hollow passages  420  can be through passages, e.g., running from one end of the wall panel to an opposite end of the wall panel. As shown, the hollow passages can have an oval profile  427 , e.g., a cross section of the hollow passage can show an oval shape. Other shapes can be used, such as a rectangular shape or a polygon shape. 
     The wall panel  400  can have a length  414 , which can be long enough to cover the vertical length of the house, such as from the floor to the ceiling of one story. The length  414  can be longer than 2 m, longer than 3 m, or longer than 4 m. The wall panel  400  can have a width  412 , which can cover the horizontal length of the house, such as from a pillar to another pillar. The wall panel  400  can be a wall piece, e.g., multiple wall pieces can be assembled to form a wall panel, spanning the horizontal length of the house between two pillars. The wall piece can have a width of longer than 1 m, shorter than 2 m, or can be about 1.2 m. The wall panel  400  can have a thickness  416 , which can be longer than 10 mm, or can be longer than 100 mm or 200 mm. 
       FIG. 4B  shows a configuration of a wall panel  401 , including horizontal passages  421  and vertical passages  431  embedded in a concrete material  411 . The horizontal passages  421  can pass substantially horizontal to the floor or to the ceiling plane. The vertical passages  431  can pass substantially vertical to the floor or to the ceiling plane. 
       FIG. 4C  shows a configuration of a wall panel  401 , including horizontal passages  422  and hollow voids  442  embedded in a concrete material  412 . The horizontal passages  422  can pass substantially horizontal to the floor or to the ceiling plane. The hollow voids  442  can be distributed in the concrete material of the wall panel. 
       FIG. 4D  shows a configuration of a wall panel  403 , in which the hollow passages  423  extend to a surface of the wall panel  403 . The wall panels  403  can include a concrete material  413  forming a wall surface  463  and multiple horizontal ridges  473  forming the hollow passages  423 . 
       FIG. 4E  shows a configuration of a wall panel  404 , in which the hollow voids  424  extend to a surface of the wall panel  404 . The wall panels  404  can include a concrete material  414  forming a wall surface  464  and a protrusion mesh  474  forming the hollow voids  424 . 
     In some embodiments, the concrete wall panels can be reinforced with a mesh, such as a steel mesh. The mesh can be a net from steel wire, or multiple steel wires interlacing or interlocking to form a grid. The mesh can be used to strengthen the wall panels, such as preventing the wall panels from shattering. The mesh can be placed inside and along a surface of the wall panels. 
       FIGS. 5A-5E  illustrate configurations for wall panels having meshes according to some embodiments. In  FIG. 5A , a wall panel  500  can include a concrete material or a cement material  510 . The wall panel can include hollow passages  520 , passing from one end of the wall panel to an opposite end of the wall panel. A mesh  550  can be disposed along a surface of the wall panel, and can be placed inside the wall panel. The mesh can be placed at a distance greater than 10 mm, 20 mm, 30 mm, or 50 mm from a surface of the wall panel. The mesh can be placed at a middle of an outer surface  561  and inner surfaces, such as surfaces  562  made from the hollow passages  520 , hollow pockets or voids in the wall panel. 
     Different configurations for the mesh can be used. The mesh can be configured to surround the hollow passages, or additional mesh surrounding the hollow passages can be added, in addition to a mesh along an outer surface of the wall panel. The additional mesh can be used to constructing the hollow passages, for example, tube-like meshes can be placed in a mold, and concrete paste (e.g., a mixture of cement, sand and water before hardened) can be poured on to the mold. The tube-like meshes can block all or a portion of the concrete paste to enter the volume inside the meshes, thus forming hollow passages within the concrete wall panel. 
       FIG. 5B  shows a mesh  551  with some bending portions  571 . The bending portions  571  can be used to form a part of hollow passages  521 . For example, concrete material  511  can be disposed immediately under the bending portions  571  (and maybe a little above the bending portions to cover the bending portions). The concrete material  511  can be disposed separated from the bending portions at an opposite direction to form hollow passages. 
       FIG. 5C  shows a mesh  552  together with some tube-like meshes  572 . The tube-like meshes  572  can be used to form hollow passages  522 , or a part of the hollow passages. For example, concrete material  512  can be disposed on a surface to form a thin layer of concrete, such as less than 100 mm thickness, or less than 50 mm, 30 mm, 20 mm, or 10 mm thickness. Before the concrete is hardened, a mesh  552  can be placed on the concrete layer. Another thin layer of concrete can be placed on the mesh  552 . Multiple tube-like meshes  572  can be placed on the another thin layer of concrete, and then additional concrete can be poured surrounded the tube-like meshes and covering the tube-like meshes. 
       FIG. 5D  shows a mesh  553  with some bending portions  573 . The bending portions  573  can be somewhat conformed to a shape of hollow passages  523 . Tube-like meshes or conduits  563  having the outer shape of hollow passages  523  can be placed near the bending portions. Concrete material  513  can be disposed. The tube-like meshes or conduits can prevent the concrete material from filling in the hollow passages. The tube-like meshes or conduits can be removed after the concrete is hardened. Alternatively, the tube-like meshes or conduits can be left inside the concrete wall panel. In this case, the conduits can be hollow conduits, and the hollow passages can be the hollow portion inside the hollow conduits. 
       FIG. 5E  shows a mesh  554  together with some conduits  564 . The conduits  564  can be used to form hollow passages  524 , or a part of the hollow passages. For example, concrete material can be disposed, followed by the mesh, and then additional concrete material. The conduits can be placed on the concrete material, followed by more concrete material. The conduits can be removed after the concrete is hardened. Alternatively, the conduits can be left inside the concrete wall panel. In this case, the conduits can be hollow conduits, and the hollow passages can be the hollow portion inside the hollow conduits. 
     As shown, the bending portions and the tube-like meshes have a curve cross section, such as circular or oval tubes. Other configurations of bending portions and the tube-like meshes can be used, such as bending portions or the tube-like meshes having rectangular or polygon cross section shapes. 
     In some embodiments, the concrete wall panels can have end portions configured for ease of assembling with other wall panels or with the construction beams (vertical pillars or horizontal joists for the house). The end portions can include configurations for the concrete, such as a straight end portion or a step end portion. The straight end portions can allow the wall panels to have uniform shapes. The step end portions can allow the wall panels to be adjusted, e.g., the wall panels can be moved relative to the step end portions without any shown gaps. 
       FIGS. 6A-6E  illustrate configurations for end portions of wall panels according to some embodiments.  FIG. 6A  shows a straight end portion  670  for a wall panel  600 . The straight end portion can be a flat and perpendicular to the large wall panel surfaces. In general, the straight end portion can be slightly curved and can make a small angle with the wall panel surfaces. The wall panel  600  can include a cement material  610 , forming a concrete wall panel. The wall panel  600  can include a mesh  650 , disposed along the wall panel surface, for example, to strengthen the structural integrity of the wall panel. The wall panel  600  can include hollow passages  620 , running from the end portion  670  to an opposite end portion. The straight end portion can allow two wall panel to be placed next to each other, to form a larger wall panel. In the present specification, the term wall panel and wall piece can be used interchangeably. A wall piece can be a portion of a wall panel, if the wall panel has multiple wall pieces. A wall piece can be a wall panel, if the wall panel has only one wall piece. 
       FIG. 6B  shows a step end portion  671  for a wall panel  601 . The step end portion can have a protrusion or a recess at the end portion of the wall panel. In general, the step end portion can have different sizes and shapes, which can allow two step end portions of two adjacent wall panels to mate to each other with a tolerance. For example, a step end portion of a wall panel can have a protrusion at an inner surface of the wall panel (e.g., the surface facing the inside of the house when the wall panels are assembled into the house). A step end portion of another wall panel can have a protrusion at an outer surface of the wall panel (e.g., the surface facing the outside of the house when the wall panels are assembled into the house). The two wall panels can be assembled, with the step end portions mated to each other, e.g., the step end portions overlap each other. The step end portions can increase the tolerance of the width of the wall panels, since the distance  675  between two wall panels can be adjusted without any gap between the two wall panels. The wall panels can have a width smaller than a nominal width, and with straight end portions, the small width wall panels can have a gap between the wall panels. With the step end portions, the small width wall panels can be assembled without any exposed gaps. 
     The wall panel  601  can include a cement material  611 , forming a concrete wall panel. The wall panel  601  can include a mesh  651 , disposed along the wall panel surface, for example, to strengthen the structural integrity of the wall panel. The wall panel  601  can include hollow passages  621 , running from the end portion  671  to an opposite end portion. 
     Other end portions can be used for the wall panels, such as curved end portions, zigzag end portions (which is a variation of the step end portions, with the end surface making an angle with the middle surface instead of a right angle), middle pin end portions (which includes a protrusion at a middle of the wall panel thickness), and middle recess end portions (which includes a recess at a middle of the wall panel thickness). 
     The wall panels can have different configurations of end portions. For example, a wall panel can have straight end portions at both ends of the wall panels. The wall panels can have different end portions at the ends, such as a straight end portion at one end and a step end portion at another end. The wall panels can have both step end portions at both ends. Different step end portions can be used at different ends of the wall panels. 
       FIG. 6C  shows a configuration in which a wall panel have step end portions at two ends, and the protrusion of the end portions are located at different surfaces of the wall panel, e.g., a protrusion at an inner wall surface and a protrusion at an outer wall surface. A wall panel  602  can have two step end portions, for example, at a left end and at a right end of the wall panel. At the left end, the step end portion can include a protrusion  680 , for example, at a wall surface  640 , such as an inner wall of the house; or a recess  660  at a wall surface  641 , such as an outer wall of the house. At the right end, the step end portion can include a protrusion  681 , for example, at the outer wall  641  of the house; or a recess  661 , for example, at an inner wall  640  of the house. The wall panel  602  can include a cement material  612 , forming a concrete wall panel. The wall panel  602  can include meshes  652 , disposed along the two wall panel surfaces, for example, to strengthen the structural integrity of the wall panel. The wall panel  602  can include hollow passages  622 , running from the end portion to an opposite end portion. 
       FIG. 6D  shows a configuration in which a wall panel have step end portions at two ends, and the protrusion of the end portions are located at a same surface of the wall panel, e.g., both protrusions at an inner wall surface or at an outer wall surface. A wall panel  603  can have two step end portions, for example, at a left end and at a right end of the wall panel. At the left end, the step end portion can include a protrusion  682 , for example, at a wall surface  642 , such as an inner wall of the house; or a recess  662  at a wall surface  643 , such as an outer wall of the house. At the right end, the step end portion can include a protrusion  683 , for example, at the inner wall  642  of the house; or a recess  663 , for example, at an outer wall  643  of the house. The wall panel  603  can include a cement material  613 , forming a concrete wall panel. The wall panel  603  can include a mesh  653 , disposed along a wall panel surface. The wall panel  603  can include hollow passages  622 , running from the end portion to an opposite end portion. 
     In some embodiments, the present invention discloses wall panels having metal-based attachments, thus can facilitate the coupling of the wall panels with other wall panels or with beams (vertical pillars or horizontal joists), e.g., through the coupling of metal to metal. For example, two wall panels can have metal-based attachments, e.g., attachments having a metal material, such as attachments made of steel or other alloys. The two wall panels can be coupled to each other through the attachments, for example, by welding, by bolting with bolts (the attachments can function as nuts), or by bolting with bolts and nuts. 
     The wall panels with metal-based attachments can be used to coupled to metal beams, such as beams having a metal material or beam having a metal-based attachment. For example, a pillar can be made of a metal material, such as steel or other metal alloys (e.g., alloy having metal as an element in the material composition). The pillar can be coupled to the wall panels through the metal-based attachments, for example, by welding, by bolting with bolts (the attachments can function as nuts), or by bolting with bolts and nuts. 
     In some embodiments, the present invention discloses a pre-fabricated house and construction methods to form the pre-fabricated house. The pre-fabricated house can include metal-based beams (e.g., vertical or horizontal joists) and wall panels having metal-based attachments. The beams and the wall panels can be coupled through the metal-base portions, e.g., between the metal based beams and the metal-based attachments of the wall panels. The wall panels can be formed of various materials, such as sheet rock, wood, brick, cement, concrete, and any other construction materials. 
     In some embodiments, the present invention discloses pre-fabricated houses having concrete wall panels, e.g., wall panels having a cement material. The concrete wall panels can have attachment elements, or attachments, for ease of coupling. For example, the attachments can include a metal material, such as an iron based material like steel, which can be used for welding or accepting a bolt, thus allowing easier coupling as compared to a concrete material. The attachments can be formed at an end portion of the wall panel, for example, to allow coupling of two wall panels, or to allow coupling of a wall panel with a beam, such as a vertical pillar or a horizontal joist. 
     The following description describes concrete wall panels having metal-based attachments for coupling with other wall panels or with beams of the house. The invention is not so limited, and the description can be applied to wall panels made of other materials with metal-based attachments. 
       FIGS. 7A-7D  illustrate configurations of attachments for wall panels according to some embodiments. In  FIG. 7A , a wall panel can have a straight end portion with protruded attachments  760 , extended from the straight end portion. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  710 , with hollow passages  720 . As shown, the hollow passages  720  have an oval shape, but other shapes can be used. The attachments can be placed near the hollow passages. 
     In  FIG. 7B , a wall panel can have a straight end portion with protruded attachments  761 , extended from the straight end portion. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  711 , with hollow passages  721 . As shown, the hollow passages  721  have a rectangular shape, but other shapes can be used. The attachments can be placed in a middle of the wall panel thickness, between the hollow passages. 
     In  FIG. 7C , a wall panel can have a step end portion with an attachment  762 , coupled to the step of the step end portion. The attachment can be placed at the step portion, such as at a face parallel to a wall panel surface. The attachment can run along a length of the wall panel, for example, from a top portion to a bottom portion of the wall panel. The wall panel can include a cement or concrete material  712 , with hollow passages  722 . The attachments can have bent configurations, for example, to run around the hollow passages. Other attachment configurations can also be used, such as straight attachments running near and along a surface of the wall panel. 
     In  FIG. 7D , a wall panel can have a step end portion with one or more attachments  763 , coupled to the step of the step end portion. The attachment can be placed at the step portion, such as at a face parallel to a wall panel surface. The attachment can run along a portion of a length of the wall panel, for example, between two hollow passages of the wall panel. The wall panel can include a cement or concrete material  713 , with hollow passages  723 . The attachments can have bent configurations, for example, to run from a middle of a hollow passage to a middle of a portion of the wall panel not having the hollow passages. Other attachment configurations can also be used, such as straight attachments running along an exposed surface of the wall panel. 
     In some embodiments, the attachments can be interlocked or secured with the wall panel material. For example, the attachments can be placed at an exposed surface of the wall panel, together with a locking element embedded within the wall panel. As shown, the attachment  763  can be disposed at an exposed surface of the wall panel, and the attachment  763  can be coupled to locking elements  773 , which are embedded in the wall panel. The locking elements  773  can have an inverse T shape, which can secure the attachment  763 . Other configurations for the locking elements can be used, such as star shapes, hook shapes, inverse triangular shapes, and any shapes that can present a physical action which can prevent the attachment from being loosened from the wall panel surface. 
       FIGS. 8A-8F  illustrate configurations of attachments for wall panels according to some embodiments. In  FIG. 8A , a wall panel can have a straight end portion with protruded attachments  860 , extended from the straight end portion. The attachments can be coupled to a surface of the wall panel, such as the surface of the straight end portion. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  810 , with hollow passages  820 . 
     In  FIG. 8B , the protruded attachments  861  can have a portion  871  embedded in the wall panel. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  811 , with hollow passages  821 . 
     In  FIG. 8C , the protruded attachments  862  can have a portion  872  embedded in the wall panel in a locking configuration, such as the embedded portion near the wall panel surface has a smaller volume than the embedded portion farther from the wall panel surface. The locking configurations can include a star shape, a inverse triangle shape, or a T shape. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  812 , with hollow passages  822 . 
     In  FIG. 8D , a wall panel can have a straight end portion with an attachment  863 , coupled to the straight wall of the straight end portion. The attachment can be protruded from the straight wall. The attachment can run along a length of the wall panel, for example, from a top portion to a bottom portion of the wall panel. The wall panel can include a cement or concrete material  813 , with hollow passages  823 . The attachments can have bent configurations, for example, to run around the hollow passages. Other attachment configurations can also be used, such as straight attachments running near and along a surface of the wall panel. 
     In  FIG. 8E , a wall panel can have a straight end portion with an attachment  864 , coupled to the straight wall of the straight end portion. The attachment can be coupled to the straight wall, such as running along and covering a length of the wall panel, for example, from a top portion to a bottom portion of the wall panel. The wall panel can include a cement or concrete material  814 , with hollow passages  824 . The attachment  864  can be attached to an outer surface of the straight wall, or can be embedded inside the straight wall. 
     In  FIG. 8F , a wall panel can have a straight end portion with an attachment  865 , coupled to the straight wall of the straight end portion. The attachment can include a coupling element  875 , such as a hole or a tap  875  made in the attachment  865 . The wall panel can include a cement or concrete material  815 , with hollow passages  825 . The attachment  865  can be attached to an outer surface of the straight wall, or can be embedded inside the straight wall. 
       FIGS. 9A-9F  illustrate configurations of attachments for wall panels according to some embodiments. In  FIG. 9A , a wall panel can have a step end portion with attachments  960  coupled to a wall portion of the step end portion. The attachments can have multiple pieces, separated from each other. The wall panel can include a cement or concrete material  910 , with hollow passages  920 . 
     In  FIG. 9B , a wall panel can have a step end portion with attachments  962  coupled to two surfaces  972  of the step end portion. In  FIG. 9C , a wall panel can have a step end portion with attachments  961  coupled to two surfaces of the step end portion, together with attachments  972  coupled to another surface of the wall panel. 
     In  FIG. 9D , a wall panel can have a step end portion with attachments  963  coupled to a all portion of the step end portion. The attachment can have a coupling element  973 , such as a hole or a tap in the attachment  963 . In  FIG. 9E , a wall panel can have a step end portion with attachments  964  coupled to a all portion of the step end portion. The attachment can have a coupling element  974 , such as a hole or a tap in the attachment  964 . The hole or tap  974  can be extended to the wall panel, for example, the wall panel can have a hole passing through, from the attachment to the other surface of the wall panel. In  FIG. 9F , a wall panel can have a step end portion with attachments  965  coupled to two surfaces of the step end portion, together with attachments  966  coupled to another surface of the wall panel. The attachment can have a coupling element  975 , such as a hole or a tap in the attachments  965  and  966 . The hole or tap  975  can be extended to the wall panel, for example, the wall panel can have a hole passing through, from the attachment  965  to the attachment  966 . 
     In some embodiments, the concrete wall panels can be formed with electrical or mechanical couplings, such as electrical outlets or electric connections for electrical devices (lights, fans, etc), or mechanical hooks for attaching fixtures such as clocks, pictures, etc. The wall panels can have hollow passages connecting the electrical couplings, so that electrical wires can pass to these couplings. For example, horizontal hollow passages can be used for coupling between wall panels, and vertical hollow passages can be used for coupling between the horizontal hollow passages. 
       FIG. 10  illustrates a wall panel according to some embodiments. A wall panel  1000  can include a concrete or cement material  1010 , horizontal hollow passages  1020 , and reinforced mesh  1050 . Electrical outlets  1025  can be provided, for example, at a horizontal hollow passage so that electrical wire can reach the electrical outlets. Electric connections  1070  can be provided, for example, at a horizontal hollow passage so that electrical wire can reach the electrical connections. Vertical hollow passages can be included (not shown), to connect the horizontal passages. Other coupling can be included, such as opening  1027 . Mechanical  1077  coupling can be included. 
       FIG. 11  illustrates a flow chart for fabricating a concrete wall panel according to some embodiments. Operation  1100  provides a mold, wherein the mold optionally comprises a wall coupling section at an end portion, wherein the mold optionally comprises a fixture coupling for fixture attachment, wherein the mold optionally comprises hollow elements for weight reduction. 
     Operation  1110  places a first portion of a cement-based compound into the mold. Operation  1120  places a reinforced mesh into the mold. Operation  1130  places a second portion of a cement-based compound into the mold, wherein the first and second portions cover the reinforced mesh. Operation  1140  couples attachment elements to the cement-based compound. 
     In some embodiments, the present invention discloses pre-fabricated houses, and methods to assemble pre-fabricated houses, which include multiple wall panels or wall pieces assembled together to form a large wall panel. The assembling process can include metal-based elements, such as using metal-based conduits to connect the wall panels or using welding or bolting for connecting metal-based attachments in the wall panels. In the specification, the term “wall panel” and “wall piece” can be used interchangeably, in the sense that multiple wall panels or multiple wall pieces can be assembled to form a wall panel. For example, multiple wall panels can be assembled to form a larger wall panel, or multiple wall pieces can be assembled to form a wall panel. 
       FIGS. 12A-12E  illustrate configurations for assembling wall panels according to some embodiments.  FIGS. 12A and 12B  show that two wall panels can be assembled using conduits passing through hollow passages in the wall panels. The conduits can be metal-based conduits, e.g., conduits having composition including a metal material such as steel or an alloy. The conduits can be hollow tubes, such as hollow square or rectangular tubes, hollow oval or circular tubes, or hollow tubes having any cross section shapes. In  FIG. 12A , two wall panels  1200  and  1201  each having a straight end portion are assembled together. The wall panels can be concrete wall panels, including a concrete or cement material  1210 . The wall panels can have hollow passages  1220 , such as hollow passages running from one end to an opposite end of the wall panels. Hollow conduits  1270  can be inserted in the hollow passages, securing the two wall panels together. There can be a gap  1280  between the two straight end portions of the two wall panels. As shown, the hollow conduits  1270  have a rectangular shelf cross section, but other shapes can be used, such as oval shelf, or even solid rectangular or solid oval cross sections. In  FIG. 12B , two wall panels  1202  and  1203  each having a step end portion are assembled together. The wall panels can be concrete wall panels, including a concrete or cement material  1211 . The wall panels can have hollow passages  1221 , such as hollow passages running from one end to an opposite end of the wall panels. Hollow conduits  1271  can be inserted in the hollow passages, securing the two wall panels together. There can be a gap  1281  between the two step end portions of the two wall panels, however, there is no exposure or communication between the inside of the wall and the outside of the wall due to the step end portions. 
       FIGS. 12C-12E  show that two wall panels can be assembled using attachments that are coupled or formed in the wall panels. The attachments can be metal-based attachments, e.g., attachments having composition including a metal material such as steel or an alloy. The attachments can be straight plates, angle plates, or curved plates. The attachments can also have coupling elements, such as drilled holes or tap holes. In  FIG. 12C , two wall panels  1204  and  1205  each having a straight end portion are assembled together. The wall panels can be concrete wall panels, including a concrete or cement material  1212 . The wall panels can have hollow passages  1222 , such as hollow passages running from one end to an opposite end of the wall panels. The wall panels can have metal-based attachments  1262  coupled to the straight portion of the straight end portions. The attachments can be coupled together, for example, by welding  1272 . There can be a gap between the two straight end portions of the two wall panels, which can be covered by the weld. 
     In  FIG. 12D , two wall panels each having a step end portion are assembled together. The wall panels can be concrete wall panels, including a concrete or cement material  1213 . The wall panels can have hollow passages  1223 , such as hollow passages running from one end to an opposite end of the wall panels. The wall panels can have metal-based attachments  1263  coupled to the step end portions. The attachments can be coupled together, for example, by welding  1273 . There can be a gap between the two step end portions of the two wall panels, however, there is no exposure or communication between the inside of the wall and the outside of the wall due to the step end portions. Thus the weld can be spot weld, e.g., at locations for securing the wall panels together, without concerning about covering the gap. 
     In  FIG. 12E , two wall panels each having a step end portion are assembled together. The wall panels can be concrete wall panels, including a concrete or cement material  1214 . The wall panels can have hollow passages  1224 , such as hollow passages running from one end to an opposite end of the wall panels. The wall panels can have metal-based attachments  1264  coupled to a portion of the step end portion. The attachments can be coupled together, for example, by a bolt  1274  securing the attachments together. There can be a gap between the two step end portions of the two wall panels, however, there is no exposure or communication between the inside of the wall and the outside of the wall due to the step end portions. 
       FIG. 13  illustrates a flow chart for assembling wall panels according to some embodiments. Operation  1300  provides two wall panels, wherein the two wall panels comprise a cement-based compound, wherein the two wall panels optionally comprise a metal-based attachment, wherein the two wall panels optionally comprise a through straight hole from one end to an opposite end of the wall panels. Operation  1310  couples the two wall panels, wherein the coupling comprises at least one of welding the metal-based attachments of the two wall panels together, inserting a metal conduit through the through straight holes of the two wall panels, bolting the two wall panels together, optionally through the metal-based attachments, and bolting one wall panel to a metal-based attachment of another wall panel. 
     In some embodiments, the present invention discloses pre-fabricated houses, and methods to assemble pre-fabricated houses, which include wall panels assembled to beams such as vertical pillars or horizontal joists. The assembling process can include welding or bolting for connecting metal-based attachments in the wall panels with metal-based attachments in beams or with metal-based beams. 
       FIGS. 14A-14G  illustrate configurations for assembling a wall panel with a beam according to some embodiments.  FIG. 14A  shows that a wall panel  1400  can be assembled to a beam  1480  by welding the metal components. For example, the beam  1480  can include a metal material, such as steel or a metal alloy. The wall panel  1400  can include a metal-based attachment  1460 , which can be used for welding  1470  to the metal-based beam  1480 . In some embodiments, the wall panel  1400  can include a cement or concrete material  1410 , together with hollow passages  1420 . As shown, the wall panel includes a straight end portion for welding to the metal-based beam. Other configuration can be used, such as wall panels having step end portions or different types of attachments. 
       FIG. 14B  shows that a wall panel  1401  can be assembled to a beam  1481  by passing a metal-based conduit  1461  through a hollow passages  1421  of the wall panel. The beam  1481  can include a metal material, such as steel or a metal alloy, which can be welded  1471  to the conduit  1461 . In some embodiments, the wall panel  1401  can include a cement or concrete material  1411 . As shown, the wall panel includes a straight end portion for welding to the metal-based beam. Other configuration can be used, such as wall panels having step end portions or different types of attachments. 
       FIG. 14C  shows that a wall panel  1402  can be assembled to a beam  1482  by welding the metal components. For example, the beam  1482  can include a metal material, such as two C shape beams secured together by welding. The wall panel  1402  can include a metal-based attachment  1462 , which can be used for welding  1472  to the metal-based beam  1482 . In some embodiments, the wall panel can include a cement or concrete material, together with hollow passages. 
       FIG. 14D  shows that a wall panel  1403  can be assembled to a beam  1483  by bolting the metal components. For example, the beam  1483  can include a metal material, such as two C shape beams secured together by welding. The wall panel  1403  can include a metal-based attachment  1463 , which can be used for attaching a bolt  1473  to the metal-based beam  1483 . 
       FIG. 14E  shows that a wall panel  1404  can be assembled to a beam  1484  by welding the metal components. For example, the beam  1484  can include a metal material, such as two C shape beams secured together by welding. The wall panel  1404  can include a metal-based attachment  1464 , which can be used for welding  1474  to the metal-based beam  1484 . 
       FIG. 14F  shows that a wall panel  1405  can be assembled to a beam  1485  by bolting the metal components. For example, the beam  1485  can include a metal material, such as two C shape beams secured together by welding. The wall panel  1405  can include a metal-based attachment  1465 , which can be used for attaching a bolt  1475  to the metal-based beam  1485 . 
       FIG. 14G  shows that a wall panel  1406  can be assembled to a beam  1486  by passing a metal-based conduit  1466  through a hollow passages  1426  of the wall panel. The beam  1486  can include a metal material, such as two C shape beams secured together by welding, which can be welded  1476  to the conduit  1466 . 
       FIG. 15  illustrates a flow chart for assembling wall panels according to some embodiments. Operation  1500  a beam, wherein the beam optionally comprises a metal-based attachment. Operation  1510  provides a wall panels, wherein the wall panel comprises a cement-based compound, wherein the wall panel optionally comprises a metal-based attachment, wherein the wall panel optionally comprises a through straight hole from one end to an opposite end of the wall panel. Operation  1520  couples the wall panel to the beam, wherein the coupling comprises at least one of welding the metal-based attachments of the wall panel to the beam or to the metal-based attachment of the beam, inserting a metal conduit through the through straight hole of the wall panel passing through the beam, bolting the wall panel or the metal-based attachment of the wall panel to the beam or to the metal-based attachment of the beam, and bolting the beam or the metal-based attachment of the beam to the wall panel or to the metal-based attachment of the wall panel. 
     In some embodiments, the present invention discloses pre-fabricated houses, and methods to assemble pre-fabricated houses, which include beams, such as vertical pillars or horizontal joists, that have metal-based elements for coupling with a wall panel of the houses. The beams can include a metal-based attachment, which can be configured to be coupled with the wall panel, such as another metal-based attachment in the wall panel. The two metal-based attachments can be coupled by welding, or by bolting. The beams can be made of a metal material, such as steel or other alloys, and can be fabricated to include an attachment feature, which can be configured to be coupled with the wall panel, such as another metal-based attachment in the wall panel. The attachment feature and the metal-based attachment can be coupled by welding, or by bolting. 
       FIGS. 16A-16G  illustrate configurations for assembling pre-fabricated houses according to some embodiments.  FIG. 16A  shows a wall panel  1600  assembled with beams  1670  and  1680  (vertical pillars  1680  and/or horizontal joists  1670 ) through metal-based attachments  1660 . The attachment can be built in the wall panel  1600 , and then coupled to the beams  1670  and  1680  through, for example, welding or bolting. In some embodiments, the wall panel  1600  can include a cement or concrete material  1610 , and can have hollow passages  1620  within the wall panel. 
       FIG. 16B  shows a wall panel  1601  assembled with beams  1671  and  1681  (vertical pillars  1681  and/or horizontal joists  1671 ) through metal-based attachments  1661 . The attachment can be built in the beams  1671  and  1681 , and then coupled to the wall panel  1601  through, for example, welding or bolting. 
       FIG. 16C  shows a wall panel  1602  assembled with beams  1672  and  1682  (vertical pillars  1682  and/or horizontal joists  1672 ) through metal-based attachments  1662 . The attachment can be built in the wall panel  1602 , and then coupled to the wall panel  1602  through bolt  1652 . 
       FIG. 16D  shows a wall panel  1603  including multiple wall pieces (or smaller wall panels)  1603 A,  1603 B and  1603 C. The wall pieces  1603 A,  1603 B and  1603 C can include a cement or concrete material  1613 , and can have hollow passages  1623  within the wall pieces. The wall pieces can be assembled together by conduits  1653  passing through the hollow passages  1623 . The wall panel  1603  can be assembled with beams  1673  and  1683  (vertical pillars  1683  and/or horizontal joists  1673 ) through metal-based attachments  1663 . The attachment can be built in some of the wall pieces, for example, in wall pieces  1603 A and  1603 C, and then coupled to the beams  1673  and  1683  through, for example, welding or bolting. 
       FIG. 16E  shows a wall panel  1604  including multiple wall pieces (or smaller wall panels)  1604 A,  1604 B and  1604 C. The wall pieces  1604 A,  1604 B and  1604 C can include a cement or concrete material  1614 , and can have hollow passages  1624  within the wall pieces. The wall pieces can be assembled together by conduits  1654  passing through the hollow passages  1624 . The wall panel  1604  can be assembled with beams  1674  and  1684  (vertical pillars  1684  and/or horizontal joists  1674 ) through the conduits  1654 , e.g., the conduits can be extended outside of the wall panel, and can be welded to the beams  1674  and  1684 . 
       FIG. 16F  shows a wall panel  1605  including multiple wall pieces (or smaller wall panels)  1605 A,  1605 B and  1605 C. The wall pieces  1605 A,  1605 B and  1605 C can include a cement or concrete material  1615 , and can have hollow passages  1625  within the wall pieces. Each wall piece can be placed between beams, such as between vertical pillars  1685  and dividing beams (or studs)  1655  and horizontal joists  1645 . The wall pieces can be assembled together by conduits  1655  passing through the hollow passages  1625  and the dividing beams (or studs)  1655 . The wall panel  1605  can be assembled with beams  1675  and  1685 , (vertical pillars  1685  and/or horizontal joists  1675 ) through metal-based attachments  1665 . The attachment can be built in some of the wall pieces, for example, in wall pieces  1605 A and  1605 C, and then coupled to the beams  1675  and  1685  through, for example, welding or bolting. 
       FIG. 16G  shows a wall panel  1606  including multiple wall pieces (or smaller wall panels)  1606 A,  1606 B and  1606 C. The wall pieces  1606 A,  1606 B and  1606 C can include a cement or concrete material  1616 , and can have hollow passages  1626  within the wall pieces. Each wall piece can be placed between beams, such as between vertical pillars  1686  and dividing beams (or studs)  1656  and horizontal joists  1646 . The wall pieces can be assembled together by conduits  1656  passing through the hollow passages  1626  and the dividing beams (or studs)  1656 . The wall panel  1606  can be assembled with beams  1676  and  1686  (vertical pillars  1686  and/or horizontal joists  1676 ) through the conduits  1656 , e.g., the conduits can be extended outside of the wall panel, and can be welded to the beams  1676  and  1686 . 
     In some embodiments, the present invention discloses pre-fabricated houses, and methods to assemble pre-fabricated houses, which include beams, such as vertical pillars that have metal-based elements for coupling with a foundation of the houses. The beams can include a metal-based attachment, which can be configured to be coupled with the foundation, such as another metal-based attachment in the foundation. The two metal-based attachments can be coupled by welding, or by bolting. The beams can be made of a metal material, such as steel or other alloys, and can be fabricated to include an attachment feature, which can be configured to be coupled with the wall foundation, such as another metal-based attachment in the foundation. The attachment feature and the metal-based attachment can be coupled by welding, or by bolting. 
       FIGS. 17A-17F  illustrate configurations for assembling pre-fabricated houses according to some embodiments.  FIG. 17A  shows a metal pillar  1700 , e.g., a pillar having a metal material  1710 , such as made of steel or other alloys. The metal pillar  1700  can have a metal-based attachment  1720 , which can be secured to the metal pillar, for example, by welding  1730 . Other configurations can also be used, such as the metal pillar having an attachment feature which is machined from the pillar material, or a metal-based attachment secured to the pillar by bolting. 
     The metal based attachment  1720  can be secured to a foundation  1750 , e.g., coupled to a metal-based attachment  1740  of the foundation. For example, the foundation can include a cement or concrete material, with metal reinforced elements. The foundation can include metal-based poles  1740 , which are secured to the foundation, and which are configured to form an attachment to a vertical pillar. The vertical pillar  1700  can be placed on the foundation  1750 , with the metal-based attachment  1720  of the pillar coupled to the metal-based attachment  1740  of the foundation. For example, the attachment  1720  can include through holes, and the attachment  1740  can include bolts, which can pass through the through holes of the attachment  1720 . The pillar can be secured to the foundation, for example, by nuts bolting on the bolts, or by welding the bolts to the holes. 
       FIGS. 17B and 17C  show a metal pillar  1701 / 1702 , e.g., a pillar having a metal material  1711 / 1712 , such as made of steel or other alloys. For example, the metal pillar  1701  can be two C shape beams secured together by welding. The metal pillar  1701 / 1702  can have an attachment feature  1721 / 1722  which is machined from the pillar material. The metal based attachment  1721 / 1722  can be secured to a foundation  1751 / 1752 , e.g., coupled to a metal-based attachment  1741 / 1742  of the foundation, respectively. 
       FIG. 17D  shows a concrete pillar  1703 , e.g., a pillar having a cement material  1713 , such as a mixture of cement, sand and water. The concrete pillar  1703  can have a metal-based attachment  1723 , which can be secured to metal-based reinforced elements  1763  of the pillar, for example, by welding  1733 . The metal based attachment  1723  can be secured to a foundation  1753 , e.g., coupled to a metal-based attachment  1743  of the foundation. For example, the foundation can include a cement or concrete material with metal reinforced elements  1763 . The foundation can include metal-based poles  1743 , which are secured to the foundation, and which are configured to form an attachment to a vertical pillar. The vertical pillar  1703  can be placed on the foundation  1753 , with the metal-based attachment  1723  of the pillar coupled to the metal-based attachment  1743  of the foundation. 
       FIGS. 17E and 17F  show different configurations of concrete pillars attaching to foundations. Metal-based attachment  1724  can include coupling elements  1734  which are coupled to the reinforced elements  1764  of the concrete pillar  1704 . Alternatively, metal-based attachment  1725  can be bolted by a coupling element  1735  to secure the attachment  1725  to the concrete pillar  1705 . 
       FIG. 18  illustrates a flow chart for assembling wall panels according to some embodiments. Operation  1800  provides a beam, wherein the beam optionally comprises a metal-based attachment. Operation  1810  provides a wall panels, wherein the wall panel comprises a cement-based compound, wherein the wall panel optionally comprises a metal-based attachment, wherein the wall panel optionally comprises a through straight hole from one end to an opposite end of the wall panel. Operation  1820  couples the wall panel to the beam, wherein the coupling comprises at least one of welding the metal-based attachments of the wall panel to the beam or to the metal-based attachment of the beam, inserting a metal conduit through the through straight hole of the wall panel passing through the beam, bolting the wall panel or the metal-based attachment of the wall panel to the beam or to the metal-based attachment of the beam, and bolting the beam or the metal-based attachment of the beam to the wall panel or to the metal-based attachment of the wall panel. 
     In some embodiments, the present invention discloses a pillar structure that can allow construction of houses having various sizes and shapes. 
       FIGS. 19A-19D  illustrate various configurations for assembling pre-fabricated houses according to some embodiments. The pillars can include two C shape beams secured together, for example, by welding. The C shape beams can be attached with an offset amount, thus providing multiple surfaces for coupling with a L shape beam of the wall panel. For example, a pillar can have 6 external surfaces for connection, two ( 1961  and  1962 ) at the middle portion of the C pattern, and four ( 1971 ,  1972 ,  1973 , and  1974 ) at the outer portions of the C pattern. The pillar can have 4 internal surfaces for connection at each inner protruding portion ( 1981 ,  1982 ,  1983 , and  1984 ) of the C shape beams. 
     For example, as shown in  FIG. 19A , wall panel  1931  can have a L shape end beam  1941  coupled to an outer C portion  1911 . Wall panel  1932  can have a L shape end beam  1942  coupled to a middle C portion  1912 . Thus the pillars can allow construction of different housing configurations depending on the rotation and attachment point of the pillars. 
       FIGS. 20A-20C  illustrate various configurations for assembling pre-fabricated houses according to some embodiments. The houses can have middle wall panels. 
       FIG. 21  illustrates a configuration for assembling pre-fabricated houses according to some embodiments. The house can have multiple rooms, divided by middle wall panels. 
       FIGS. 22A-22C  illustrate a process for constructing a house according to some embodiments. In  FIG. 22A , pillars  2210  and wall panels  2230  and  2237  can be transported to a construction site. The wall panels can be pre-fabricated according to the house, for example, having proper length and attachment beam connections, such as wall panels  2230  and  2237  having different attachment beam connections. 
     In  FIG. 22B , a foundation can be first constructed at the construction site. A floor  2200  can be formed on the foundation. Pillars  2210  can be attached to the floor, or to the foundation. In  FIG. 22C , wall panels  2230  and  2237  can be attached to the pillars  2210 , such as by bolting  2270 , and/or by welding. 
       FIG. 23  illustrates a configuration of wall panel and pillar attachments according to some embodiments. House  800  can include multiple wall panels  830 , which can attach to pillar  810  in different configurations to form a house having a desired size and shape. 
       FIGS. 24A-24B  illustrate a process for forming a two story house according to some embodiments. In  FIG. 24A , a floor panel  2490  can be installed, for example, on a foundation  2495 . Pillars  2410 ,  2415 , and  2417  can be attached to the floor panel  2490 , or alternatively, attached to the foundation through the floor panel. For example, pillar  2410  can be welded  2485  to the floor panel, e.g., to a metal frame of the floor panel. Pillar  2415  can be bolted  2470  to the foundation through the floor panel, e.g., to bolts secured to the foundation and protruded to the floor panel. Alternatively, the pillar can be bolted to the floor panel, e.g., to bolts that are secured to the frame of the floor panel. The foundation can be protruded through the floor panel, and the pillar can be welded  2486  or bolted  2471  directly to the foundation. 
     Top floor panels  2497  can be secured to the pillars  2410 ,  2415 , and  2417 . New pillars can be secured to the top floor panels, or to the existing pillars under the top floor panels. 
     In  FIG. 24B , wall panels  2430  and  2435  can be secured to the pillars. The wall panels can be pre-fabricated to include all necessities, such as window  2420 , or doors, or other elements such as electrical connections or outlets. Alternatively, the wall panels can include outer wall plates that are pre-fabricated. The inner wall plates can be installed after the house structure is completed. The electrical connections such as wiring and outlets can be installed at the interior of the wall panels, and then the inner wall plates can be installed. 
     In some embodiments, the wall panels can be installed before forming the new pillars for the top floor. Alternatively, the wall panels can be installed before forming the top floor panels. 
       FIG. 25  illustrates a flow chart for constructing a pre-fabricated house according to some embodiments. Operation  2500  prepares a foundation for a house. Operation  2510  couples first multiple pillars to the foundation, wherein the pillars comprise two C-shape beams offsetly attached back to back. Operation  2520  attaches multiple walls to the multiple pillars, wherein the multiple walls comprise L-shape beams coupled to C-shape beams coupled to ends of the multiple walls. Operation  2530  couples a second floor on the multiple pillars. Operation  2540  couples second multiple pillars to the second floor. 
       FIGS. 26A-26G  illustrate wall panels according to some embodiments. In  FIG. 26A , an attachment beam  2640  is shown, which can be used for attaching to a pillar. The attachment beam  2640  can have a L shape cross section, with one part of the L shape attached to an end beam of a wall panel, and the other part of the L shape attached to a pillar. 
     In  FIG. 26B-26D , various wall panels without an attachment beam are shown. A wall panel  2630  can have end beams  2660  disposed at edges of a wall plate  2650 . The end beams can be at two opposite edges or at all four edges of the wall plate. The end beams can have a C shape cross section. The attachment beams, for example attachment beams  2640 , can be coupled to the end beams  2660 . The coupling can be by bolting or by welding. The coupling can be pre-fabricated, e.g., welded according to the design of the house. The coupling can be performed at the construction site, e.g., tack welded during assembling with the pillar, and then removed for final weld before re-assembled with the pillar. 
     A wall panel  2631  can have a frame attached together. For example, end beams  2661  and middle beams  2691  can be welded together to form a frame for the wall panel. Wall plates  2651  can be coupled to the surfaces of the frame to form a wall panel. 
     Alternatively, a wall panel  2632  can have a frame with end beams  2662  and middle beams  2692 . One wall plate  2652  can be coupled to a surface, such as an external surface, of the wall panel. After complete the structural construction for the house, e.g., the floor panels, the pillars, the wall panels, and the roof panels have been assembled, electrical wiring and/or gas line running can be installed. The other wall plate of the wall panel  2632  can be installed to cover the electrical wiring. 
     In  FIG. 26E-26G , various wall panels with attachment beams are shown. An attachment beam  2643  can have a T shape cross section, and can be attached, e.g., welded, to end beam  2663  of wall panel  2633 . The attachment beam  2643  can be symmetric, e.g., the attachment portion can be symmetric with respect to a center line of the wall panel. The attachment beams  2643  and  2673  at two end of the wall panel  2633  can be symmetric, e.g., both attachment portions can be symmetric with respect to a center line of the wall panel. 
     The attachment beam  2644  of wall panel  2634  can be asymmetric, e.g., the attachment portion can be asymmetric with respect to a center line of the wall panel. The attachment portion of attachment beam  2644  can be attached to a mated attachment portion of a pillar  2614 , with the center line disposed between the two attachment portions, thus providing a symmetrical configuration after coupling. In wall panel  2634 , the attachment portions of two opposite attachment beams  2644  and  2674  can be a rotating image, e.g., one attachment portion can be obtained by rotating the other attachment portion. In wall panel  2635 , the attachment portions of two opposite attachment beams  2645  and  2675  can be a mirror image, e.g., one attachment portion can be obtained by reflecting the other attachment portion. 
     In some embodiments, the present invention discloses methods and systems for improved alignments between components in pre-fabricated houses. The components can be pre-attached for proper matching, and then disassembled for secured attachment before re-assembling. 
       FIGS. 27A-27C  illustrate a process for alignment improvement according to some embodiments. In  FIG. 27A , attachment beams  2740  and  2741  can be attached to pillars  2710  and  2711 , respectively, through bolts such as  2770 . A wall panel  2730  can be brought to couple with the attachment beams  2740  and  2741 . Tack weld  2780  can be used to attach the attachment beams  2740  and  2741  to the wall panel  2730 . 
     Alternatively, an attachment beam  2740  can be attached to the wall panel  2730 , either temporarily (e.g., by tack weld) or permanently (e.g., by secured weld). The wall panel  2730  with the attachment beam  2740  can be attached to pillar  2710 . Other attachment beam  2741  can be coupled to pillar  2711  and tack welded to the wall panel  2730 . Thus the attachment of the attachment beams to the wall panel can occur after performing an alignment, thus allowing proper alignment of the wall panel with pillars. 
     In  FIG. 27B , the attachment beams can be secured to the wall panel, for example, by a permanent weld  2785 . The permanent weld by be performed when the wall panel is attached to the pillars, or can be performed after the wall panel is removed from the pillars. 
     In  FIG. 27C , the wall panel can be re-installed after securing the attachment beams. The re-installation can be performed with nuts and bolts  2770 , or with welding. Since the positions of the attachment beams have been proven to be mated properly with the pillars, the re-installation of the wall panel should fit perfectly. 
       FIG. 28  illustrates a flow chart for alignment improvement according to some embodiments. Operation  2800  prepares a foundation for a house. Operation  2810  couples first multiple pillars to the foundation, wherein the pillars comprise two C-shape beams offsetly attached back to back. Operation  2820  puts multiple walls to the multiple pillars, wherein the multiple walls comprise C-shape beams coupled to ends of the multiple walls. Operation  2830  loosely couples L-shape beams to the pillars and the walls. Operation  2840  removes the coupling between the L-shape beams and the pillars to obtain the walls having L-shape beams loosely attached. Operation  2850  securely attaches the L-shape beams to the walls. Operation  2860  attaches the walls to the pillars, wherein the walls are attached to the pillars through the L-shape beams. 
     In some embodiments, the present invention discloses methods and systems for constructing portable houses. Pillars can be installed, for example, on floor panels. The pillars can have channels along the length of the pillars. Wall panels can have mating elements that fit in the channels of the pillars. The wall panels can be raised to a position above the pillars and then dropped to the channels of the pillars, so that the mating element fit in the channels. Additional attachment process can be added, for example, by welding or bolting the wall panels to the pillars, to secure the wall panels to the pillars. 
       FIGS. 29A-29B  illustrate a process for installing wall panels according to some embodiments. Pillars  2910  can be installed on floor panels  2900 . The pillars  2910  can have channels  2912  along the length of the pillars, e.g., parallel to the pillars. Wall panels  2930  can have end beams  2940 , which have mating elements  2942  that can fit in the channels  2912 . The wall panels  2930  can be raised and then slide along the channels  2912  so that the mating element  2942  is within the channels  2912 . The channels thus can secure the wall panels in place, even without any additional attachment means. Alternatively, the wall panels can be welded or bolted to the pillars, e.g., the end beams  2940  can be welded to the pillars  2910 , or the mating element  2942  can be bolted to the pillars  2910 . The pillars  2910  can have a middle channel  2912 . 
       FIGS. 30A-30B  illustrate a process for installing wall panels according to some embodiments. Pillars  3010  can be installed on floor panels  3000 . Wall panels  3030  can have end beams  3040 , which have channels  3042  that can fit the pillars  3010 . The wall panels  3030  can be raised and then slide along the pillars  3010  so that the channels  3042  covers the pillars  3010 . The channels thus can secure the wall panels in place, even without any additional attachment means. Alternatively, the wall panels can be welded or bolted to the pillars, e.g., the end beams  3040  can be welded or bolted to the pillars  3010 . 
     In some embodiments, the prefab house can include multiple beams, with the multiple beams configured to be secured to a foundation to form a frame of the prefab house. The prefab house can include one or more wall panels. At least a wall panel can be disposed between two beams of the multiple beams. The wall panel is disposed between the two beams in such as way so that the at least a wall panel can be movable in a direction along a length of the two beams. The wall panel can be disposed between the two beams in such as way so that the wall panel is constrained in directions perpendicular to the length of the two beams. 
     In some embodiments, the beams can include a channel running along from one end to an apposite end of the beam, with the wall panel having a structure that fits in the channel. 
     The wall panel can include a channel running along from one end to an apposite end of the wall panel. The beams can include a structure that fits in the channel. 
     The beams of the multiple beams can include at least a first mating element along a length of the each beam. The wall panel can include a cement material. The wall panel can include two second mating elements at two ends of the at least a wall panel. The first and second mating elements are configured for mating with each other. The wall panel can be disposed between the at least two beams with the second mating elements fitted into the first mating elements of the at least two beams. 
     The multiple beams, the wall panels, and floor panels and ceiling panels can be pre-fabricated in a factory before being brought to a construction site for assembling the prefab house. The wall panel can include a cement or concrete material coupled to metal connectors, such as a metal coupler. The multiple beams and at least a frame of the floor panels or the ceiling panels can include a metal material. 
       FIG. 31  illustrates a flow chart for constructing a portable house according to some embodiments. Operation  3100  prepares a foundation for a house. Operation  3110  couples multiple poles to the foundation, wherein the poles comprise C-shape or box shape beams. Operation  3120  lifts multiple walls above the multiple poles, wherein the multiple walls comprise an attachment for coupling to the multiple poles. Operation  3130  optionally secures the walls to the pillars. 
     In some embodiments, the prefab house can be formed by securing multiple beams to a foundation to form a frame of the prefab house, A wall panel can be brought to a position above the multiple beams, wherein the wall panel comprises a cement material coupled to metal connectors. The wall panel can be slide between two beams of the multiple beams, wherein the wall panel is constrained in directions perpendicular to the length of the two beams. 
     In some embodiments, the beams can include a channel running along from one end to an apposite end of the beam, with the wall panel having a structure that fits in the channel. 
     The wall panel can include a channel running along from one end to an apposite end of the wall panel. The beams can include a structure that fits in the channel. 
     The multiple beams, the wall panels, and floor panels and ceiling panels can be pre-fabricated in a factory before being brought to a construction site for assembling the prefab house. The wall panel can include a cement or concrete material coupled to metal connectors, such as a metal coupler. The multiple beams and at least a frame of the floor panels or the ceiling panels can include a metal material. 
     The beams can include a first mating element along a length of the each beam. The wall panel can include two second mating elements at two ends of the at least a wall panel. The first and second mating elements can be configured for mating with each other. The wall panel can be disposed between the at least two beams with the second mating elements fitted into the first mating elements of the at least two beams. 
     In some embodiments, the present invention discloses a prefab house and its construction and assembly. A floor panel and a ceiling panel can be fabricated, for example, using a metal frame. Multiple beams, such as 4 beams at four corners of the floor and ceiling panels, can be fabricated with a metal material. Wall panels, including doors, windows, and optionally wall outlets can be fabricated. 
     The beams can include couplers at two ends. The floor panel can include bottom couplers for coupling with foundation poles. The floor panel can include top couplers for coupling with the couplers of the beams. The ceiling panel can include couplers for coupling with the couplers of the beams. The beams can include corner beams, e.g., beams at 4 corners of the prefab house. The beams can include middle beams, e.g., beams between the 4 corner beams, for supporting the wall panels. The wall panels can be configured to be coupled to each other, or to the beams, e.g., the corner beams or the middle beams. The wall panels can include a cement or concrete material, with optionally metal connectors. 
     The components can be packaged in a secured package configuration, having the floor panel at a bottom, the ceiling panel at a top, and the wall panels and the beams are packaged and placed in a middle, so that the floor and ceiling panels sandwiching the package of beams and wall panels. The complete package configuration is secured, such as by cables or straps. 
     For construction, foundation poles can be prepared at the construction side. For example, foundation poles at 4 corners of the prefab house can be prepared. In addition, the foundation poles can be formed in between the corner poles, for supporting the prefab house. 
     The secured package can be brought to the construction site, and placed on the foundation poles, for example, by a hoist. The secured package can be packaged in such as way to expose the couplers of the floor panel. Thus the couplers of the floor panel can be secured to the foundation poles. 
     The secured package can be unsecured, e.g., the cables or straps can be removed. The removal of the secured cables or straps can occur while the hoist is still coupled to the package. Thus, the hoist can lift up again, lifting the ceiling panel from the remaining of the package, exposing the inner package of wall panels and beams. The beams can be packed so that they are at the top of the inner package, so can be easily removed first. 
     The inner package can be unsecured, e.g., unwrapped. The beams are removed from the inner package. The beams can be coupled to the floor panel. The ceiling panel can be lowered, so that the ceiling panel can be coupled to the beams. 
     The wall panels can be removed from the inner package, and assembled between the beams and the floor and ceiling panels. The wall panels can include multiple panels coupling together. The prefab house can include middle beams, e.g., beams between the 4 corner beams, to support and secure the wall panels. 
       FIGS. 32A-32F  illustrate a process for assembling a prefab house according to some embodiments. In  FIG. 32A , a secured package  3220  is hoist to a construction site, aligned to foundation poles  3210 . The secured package  3230  can include a floor panel  3221  and a ceiling panel  3222 , sandwiching an inner package  3223 . 
     In  FIG. 32B , after placing the secured package on the foundation poles, and optionally securing the floor panel to the foundation poles, the secured package is unsecured, and the hoist lifted up, separating the ceiling panel from the package. The inner package is exposed, and unwrapped. 
     In  FIG. 32C , the corner beams  3241  are removed from the inner package and coupled to the floor panel. The ceiling panel can be lowered, so that the ceiling panel is coupled  3231  to the corner beams. 
     In  FIG. 32D , the coupling between the floor panel, the ceiling panel, and the corner beams are secured. The wall panels  3240  are removed from the inner package. 
     In  FIG. 32E , the wall panels are assembled between the corner beams. The wall panels can include multiple panels, with the panels optionally mating with each other. Inner beams can also be used for supporting the wall panels. For example, a corner panel can be installed, coupling to a corner beam. A middle beam can be coupled to the free side of the panel, e.g., to the side of the panel that is not already coupled to the beam. A second panel can be installed, coupling to the corner panel through the middle beam. A second middle beam can be coupled to the corner and second panels, securing the two panels together. Subsequent panels can be repeated. 
       FIG. 32F  shows an assembled prefab house. 
       FIG. 33  illustrates a coupling configuration between a floor or ceiling panel  3310  with a wall panel or the beams  3320 . The floor or ceiling panel can include a hook configuration  3330  and  3331  for hooking with slits in the beam  3320 . The floor or ceiling panel can include a support  3332  for connecting to another floor or ceiling panel. 
       FIGS. 34A-34G  illustrate coupling configurations between wall panels according to some embodiments. In  FIG. 34A , a wall panel  3410  can include one or more plates  3411 . Two plates are shown. Attachments  3412  in a form of a cross can be coupled to the plates, having a protrusion extended from the panel, which can be used for coupling with other wall panel or with a beam. The protrusion can have different sizes, such as a longer size at one end of the wall panel and a shorter size at an opposite end of the wall panel. 
       FIG. 34B  shows a straight coupling configuration between two wall panels. A beam  3420  having a box cross section can be used to couple the two attachments of two panels. Two beams can be used, one for each side of the attachments. 
       FIG. 34C  shows another straight coupling configuration between two wall panels. A beam  3421  having a C-shape cross section can be used to couple the two attachments of two panels. Two beams can be used, one for each side of the attachments. 
       FIG. 34D  shows an angle coupling configuration between two wall panels. A beam  3422  having an angle cross section, such as a square beam, can be used to couple the two attachments of two panels. Two beams can be used, one for each side of the attachments. 
       FIG. 34E  shows another angle coupling configuration between two wall panels. A beam  3423  having a box cross section, similar to the box beam used for a straight coupling discussed above, can be used to couple the two attachments of two panels. A box beam and an angle beam can be used, one for each side of the attachments. 
       FIGS. 34F-34G  show a configuration for coupling a floor or ceiling panel to the beam. The beam  3425 , such as a box beam or a square beam, can have a slit  3426 . The floor or ceiling panel  3430  can include an attachment having a hook configuration  3431 . The attachment can be slide to the slit  3426  in the beam, and the hook configuration can be used to secure the floor or ceiling panel to the beam.