Patent Publication Number: US-11384524-B2

Title: Below-grade modular assembly

Description:
BACKGROUND 
     The present invention relates generally to modular construction techniques for erecting multi-story residences, and more specifically to a modular assembly for below-grade construction for buildings. 
     Residential and commercial buildings need a foundation to shoulder the considerable weight of the building materials, provide a flat and level base for construction, and separate wood-based materials from contact with the ground, which would cause them to rot and be infested by termites. 
     Foundations are commonly constructed with concrete. First, a hole corresponding to the size of the foundation is dug in the ground to a desired depth based on the size and height of the area of the building that is below grade, such as a basement or crawl space. Once the dirt is removed, inner and outer forms made out of wood or steel, are erected along the perimeter of the building and are spaced apart based on the designated thickness of the foundation walls. After concrete is poured in the space between the inner and outer forms and sets, the inner and outer forms are removed to reveal the foundation. Next, additional forms are erected on the foundation to form the walls of the below-grade area. Installing the forms, pouring the concrete, allowing the concrete to set and then removing the forms takes several days and sometimes weeks. This adds significant time to the overall construction schedule for residential and commercial buildings as well as increases the construction costs. 
     It is a growing trend to construct multi-story residential buildings, using modular units, especially in crowded urban areas where heavy construction equipment has difficulty maneuvering. Modular construction reduces material waste, and since the units are assembled indoors at remote locations, labor costs and working conditions are more closely controlled. Such modules are remotely constructed and assembled, transported to the building site, then placed in position using a crane. Many modules are as long as 75 feet and are assembled by stacking the modules vertically, side-by-side and end-to-end, thus providing a variety of configurations of a final building design. These modules, however, are typically made of lightweight materials that are typically not structurally strong enough for the vertical, lateral and shear forces applied to the foundation and below-grade walls by the surrounding dirt and by the weight of the building materials used to construct the floor or floors built above the below-grade area. 
     Thus, there is a need for a modular assembly for below-grade structures of residential and commercial buildings. 
     SUMMARY 
     The above-listed need is met or exceeded by the present modular assembly that is configured to be installed below grade and support one or more floors of a residential or commercial building. To save time and costs, the modular assembly is manufactured at a remote location and transported to a site for quick and easy installation in a below grade open area formed in the ground. 
     In an embodiment, a modular assembly is provided and includes a modular frame to be installed at least partially below grade and at least two panels attached to the modular frame, where the at least two panels are made of a material that withstands lateral, vertical and shear forces generated by surrounding below grade materials. The modular frame and the at least two panels are joined together as a unit prior to installation. 
     In another embodiment, a modular system for below-grade installation is provided and configured to support a multi-story building. The system includes at least two modular assemblies secured together as a unit, where each of the modular assemblies is configured to be installed at least partially below grade. The modular assemblies each include a modular frame and at least two panels attached to the modular frame, where the at least two panels are made of a material configured to withstand lateral, vertical and shear forces generated by surrounding below grade materials, and where the modular frame and at least two panels are joined together as a unit prior to installation. 
     In a further embodiment, a method of forming a modular assembly for installation below grade is provided and is configured for supporting a building, where the method includes attaching at least two panels to a modular frame at a remote location. The at least two panels are made of a material that withstands lateral, vertical and shear forces generated by surrounding below grade materials. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of the present modular assembly being transported to a hole in the ground for a building; 
         FIG. 2  is a schematic view of the present modular assembly inserted in the hole of  FIG. 1 ; 
         FIG. 3  is a schematic view of a residential building constructed on the modular assembly of  FIG. 2 ; 
         FIG. 4  is an enlarged, fragmentary perspective view of a wall of the present modular assembly on a foundation wall; 
         FIG. 5  is an exploded perspective view of the modular assembly of  FIG. 1  showing a modular frame and a panel; 
         FIG. 6  is a perspective view of another embodiment of the present modular assembly where one side of the modular assembly is open; 
         FIG. 7  is a perspective view of a further embodiment of the present modular assembly where two sides of the modular assembly are open; 
         FIG. 8  is another embodiment of the present modular assembly that includes finished interior walls; and 
         FIG. 9  is a further embodiment of the present modular assembly showing multiple modular assemblies positioned adjacent to each other. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-4 , the present modular assembly  20  is constructed to be installed below ground level  22  for structural walls of an area that is below ground level or sub-grade, such as a basement, crawl space or cellar, of residential and commercial buildings. As shown in  FIG. 1 , the modular assembly  20  is constructed at a remote location and then transported as a modular unit to a work site. Typically, as described above, a foundation and structural walls of a building are formed with poured concrete, which takes significant time due to the installation and removal of forms and additional time to allow the concrete to set and harden. The present modular assembly  20  significantly decreases the preparation and installation time because the structural walls are pre-fabricated and assembled as a modular unit at a remote location. When the modular assembly  20  arrives at a work site, it is positioned in a hole or area  24  dug for a building as shown in  FIGS. 1 and 2 . The modular assembly  20  may be positioned or placed on a foundation  26  as shown in  FIG. 3  or on gravel or other sub-surface depending on the type of building being constructed. 
     Referring to  FIGS. 4-5 , the modular assembly  20  includes a modular frame  28  made of primary structural supports  30  and secondary structural supports  32 . The primary structural supports  30  are connected together by suitable fasteners to form the outer structure of the modular frame  28 . In the illustrated embodiment, the primary structural supports  30  are made of iron, but may be made with another metal, wood or any suitable material. Also, the primary structural supports  30  are preferably two inch by twelve inch supports with a designated length but may have any suitable thicknesses, dimensions and length. In  FIG. 5 , the outer structure is made with individual primary structural supports  30 . Alternatively, two or more of the primary structural supports  30  may be connected together at the top, bottom or sides of the outer structure to enhance the strength and rigidity of the modular frame  28 . 
     After the outer structure of the modular frame  28  is assembled, a plurality of secondary structural supports  32 , i.e., studs, are attached between the upper and lower ends of the modular frame  28  to form the walls of the modular assembly  20 . The secondary structural supports  32  are preferably two inches by eight inches and a desired length but may have any suitable thicknesses, dimensions and length. Also, the secondary structural supports  32  are made of cold-formed steel, but may be made with wood or any suitable material. In an embodiment, the secondary structural supports  32  may be attached between the walls at the upper end, lower end or both the upper and lower ends of the outer structure as structural support for installing a floor, a ceiling or both a floor and ceiling on the modular assembly  20 . 
     When the construction of the modular frame  28  is finished, a plurality of sub-grade panels  34  ( FIG. 5 ) are attached to the outer surface  33  ( FIG. 4 ) of the modular frame  28 . It should be appreciated that one or more of the panels  34  may be attached to the modular frame  28 . Preferably, at least two of the panels  34  are attached to the modular frame  28  to form a desired modular assembly  20 . In the illustrated embodiment, each of the panels  34  is attached to the modular frame  28  using suitable fasteners, such as screws, that are driven through the outer surface of the panels and into the primary and/or secondary structural supports  30 ,  32  of the modular frame  28  to secure the panels to the modular frame. Alternatively, the fasteners may be inserted through the primary and secondary structural supports  30 ,  32  and then into the interior surfaces of the panels  34  to secure the panels to the modular frame  28 . 
     In the illustrated embodiment, the sub-grade panels  34  are made of a fiber-glass reinforced cementitious material that is non-rotting, termite-resistant, mold-resistant and moisture-resistant (change in moisture content of less than 10%). Further, the material used to form the panels  34  is stable, i.e., the panel will not buckle or warp like conventional wood sheathing, non-combustible and dimensionally stable and strong to support backfill loads of 2000 pounds per square foot and greater, and to carry shear and gravity loads. Preferably, each panel  34  is configured to support a uniform lateral load of up to 2083 pounds per square foot when is the secondary structural supports  32  are spaced 12 inches apart and shear wall design ratings (shear strengths) of up to 1726 pounds per linear foot. In the illustrated embodiment, the panels  34  each have a width of 4 feet and a length of 8 feet with a thickness of ¾ (0.75) inches. The panels  34  may also have a thickness of ⅝ (0.625) inches. It should be appreciated that the panels  34  may have any suitable width, length and thickness based on desired construction specifications. Additionally, each panel  34  has a weight of 5 pounds per square foot, which is significantly less than the weight of concrete walls used for conventional below-grade areas of residential and commercial buildings. The lighter weight of the panels  34  also makes transport and installation of the modular assemblies  20  easier and less expensive. 
     In an embodiment, the physical and mechanical properties of the sub-grade panels  34  are described in the following table: 
     
       
         
           
               
               
               
               
             
               
                   
                   
               
               
                   
                 TEST 
                 CONCRETE 
                 CONCRETE 
               
               
                   
                 STANDARD 
                 FOUNDATION WALL 
                 FOUNDATION WALL 
               
               
                   
                 (ASTM NO.) 
                 VALUES 
                 XD VALUES 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Fastener Lateral 
                 D1761 
                 DRY &gt; 210 lbs. [0.93 kN] 
                 DRY &gt; 210 lbs. [0.93 kN] 
               
               
                 Resistance 1   
                   
                 WET &gt; 160 lbs. [0.71 kN] 
                 WET &gt; 160 lbs. [0.71 kN] 
               
            
           
           
               
               
               
               
               
               
            
               
                 Density - Oven Dried 2   
                 C1185 
                 75 lb/ft 3   
                 [1200 kg/m 3 ] 
                 75 lb/ft 3   
                 [1200 kg/m 3 ] 
               
               
                 Weight: ¾ Inch 
                 D1037 
                 5.3 lb/ft 3   
                 [25.9 kg/m 2 ] 
                 5.3 lb/ft 3   
                 [25.9 kg/m 2 ] 
               
               
                 Thickness Delivered 
               
            
           
           
               
               
               
               
            
               
                 pH Value 
                 D1293 
                 10.5 
                 10.5 
               
               
                 Liner Variation with 
                 C1185 
                 &lt;0.10% 
                 &lt;0.10% 
               
               
                 Change in Moisture (25- 
               
               
                 90% Relative Humidity) 
               
               
                 Thickness Swell 
                 D1037 
                 Max 3.0% 
                 Max 3.0% 
               
               
                 Freeze/Thaw Resistance 
                 C1185 
                 Passed 50 cycles 
                 Passed 50 cycles 
               
               
                 Mold Resistance 
                 D3273/G21 
                 10/0 
                 10/0 
               
               
                 Water Absorption 3   
                 C1185 
                 &lt;15.0% 
                 &lt;15.0% 
               
               
                 Noncombustibility 
                 E136 
                 Passed 
                 Passed 
               
               
                 Surface Burning 
                 E84 
                 0 Flame Spread 
                 0 Flame Spread 
               
               
                 Characteristics 
                   
                 Smoke Developed Index 0 
                 Smoke Developed Index 0 
               
               
                 Long Term Durability 
                 C1185 
                 Min. 75% Retention of 
                 100% Retention of 
               
               
                   
                   
                 Physical Properties 
                 Physical Properties 
               
               
                 Water Durability 
                 C1185 
                 Min. 70% Retention of 
                 91% Retention of 
               
               
                   
                   
                 Physical Properties 
                 Physical Properties 
               
               
                 Water Vapor 
                 E96 
                 Permeance &lt; 2 Perm 
                 Permeance &lt; 2 Perm 
               
               
                 Transmission 
               
               
                 (Method B) 
               
               
                   
               
               
                 Notes: 
               
               
                   1 Fastener Lateral Resistance Measured with Applicable Fasteners 
               
               
                   2 Density Measured at Equilibrium Conditioning per Section 5.2.3.1: Tested 28 Days After Manufacturing 
               
               
                   3 Absorption Measured from Equilibrium Conditioning Followed by Emersion in Water for 48 hours 
               
            
           
         
       
     
     Additionally, in applications where plywood is typically used as on the exterior or interior of a wall, floor or ceiling, the sub-grade panels  34  may be used instead of plywood in accordance with the ANSI PWF-Specification and the CAN CSA S406 Specification. 
     As shown in  FIG. 4 , the modular assembly  20  is placed on a foundation  26 , which may be one or more foundation walls or supports, where the entire assembly is at least partially below grade to form a sub-grade area, such as a basement, of a residential or commercial building. In this embodiment, a waterproof membrane or waterproof coating  36  is applied to the exterior surfaces of the modular assembly  20  to inhibit moisture and water from penetrating the panels  34  and the seams between the panels and entering the interior space of the modular assembly. Additionally, as described below, the interior portion of the walls of the modular assembly  20  may be finished with insulation  35  placed in the spaces formed between the primary and secondary structural supports, and/or interior panels, such as wallboard panels, attached to the inner surfaces of the primary and secondary structural supports. In another embodiment, the insulation  35  is placed on the exterior or outer surface of the modular assembly between the waterproof membrane/coating  36  and the surrounding backfill soil. 
     Referring to  FIGS. 5-7 , each modular assembly  20  preferably includes at least four walls  38  made with the primary and secondary structural supports  30 ,  32  as described above. A plurality of the panels  34  are attached to the modular assembly  20  to form a modular structure having solid outer walls. The modular assembly  20  shown in  FIG. 5  has a rectangular shape but it is contemplated that the modular assembly may have any suitable shape or combination of shapes.  FIGS. 6 and 7  show different embodiments of the modular assembly. For example,  FIG. 6  shows a modular assembly  40  having one open side  42 , i.e., there are no secondary structural supports or panels attached to this side of the modular assembly. This modular assembly  40  may be positioned adjacent to or connected to another modular assembly for form a large sub-grade area. It should be appreciated that two or more of the modular assemblies may be positioned adjacent to and/or connected together to form a larger modular assembly. In another alternative embodiment shown in  FIG. 7 , the modular assembly  44  has two open sides  46 . It should be appreciated that one or more of the sides of the modular assembly may be open sides and/or a portion of the walls of the modular assembly may have openings, such as for windows, doorways or stairwells. 
     Typically, openings and holes are formed in structural below grade or sub-grade walls to enable water pipes, electrical pipes or other structures to extend through the walls. In conventional concrete walls, such openings and holes must be cut after the concrete has set. The cutting of the concrete walls requires a concrete blade and/or drill bit and generates a significant amount of dust that is hazardous to the person cutting the walls and also creates a lot of dust. The panels of the present modular assembly  20  are made to withstand the shear, lateral and vertical loads from the surrounding ground materials used as backfill, such as dirt, rock and gravel, and above grade construction while enabling conventional blades and drill bits, such as carbide-tipped blades and bits, to be used to cut openings and holes in the panels. In this way, the panels  34  of the below-grade modular assembly  20  are much easier to cut and generate significantly less dust. 
     Referring to  FIG. 8 , in another embodiment, the modular assembly  48  includes a modular frame  50  and a plurality of panels  52  secured to the modular frame as described above. In this embodiment, the modular assembly  48  also includes a finished interior walls  54  having a plurality of wallboard panels  56  secured to the modular frame  50  adjacent to the inner surfaces of the panels  52 . The finished interior walls  54  may also include tile, carpet or any suitable combination of finishing materials. In the illustrated embodiment, the seams of the wallboard panels  56  are taped and filled with joint compound and coated with at least a primer. It should be appreciated that the inner surfaces of the wallboard panels  56  may also be painted so that the modular assembly  48  is completely finished when it is installed on a foundation or other underlying surface. 
     Referring to  FIG. 9 , in a further embodiment, two or more modular assemblies  58 , i.e., modular assemblies  58   a ,  58   b  and  58   c , are secured together as a single unit. In this embodiment, the three modular assemblies  58   a ,  58   b  and  58   c  are positioned adjacent to each other and/or secured together. As shown in  FIG. 9 , the modular assemblies  58   a ,  58   b  and  58   c  may be different sizes, i.e., have different dimensions and shapes, as shown in the illustrated embodiment or one or more of the modular assemblies may have the same dimensions and shapes. Further, the modular assemblies  58   a ,  58   b  and  58   c  may be secured together at a remote location and transported to a site or modular assemblies may be individually transported to and secured at the site. Also, one or more of the modular assemblies  58   a ,  58   b  and  58   c  may have one or more open sides or openings, and/or a finished interior wall as described above. It should be appreciated that the sub-grade panels  60  are preferably four foot by eight foot panels and have a thickness of ⅝ (0.625) inches to one (1.0) inch, but may have any suitable dimensions and thickness. Also, the panels  60  may be positioned vertically or horizontally on the modular frame, such as panels  60   a  and  60   b , and may be cut to be any suitable size or shape needed to cover the exterior of the modular frame. 
     While particular embodiments of the present modular assembly have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.