Abstract:
The present invention describes a prefab wall structure which provides a reduced thermal conductivity. More particularly, the prefac wall structure comprises a stud assembly made of at least two studs secured one to the other through a contact surface lateral to said stud. This reduces the conductivity of the temperature exchange throughout the wall.

Description:
[0001]    The application claims priority to Canadian patent application No. 2,592,722, filed on Jun. 29, 2007, which is herein incorporated by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a prefab wall panel to build a prefab house, and more particularly, the present invention relates to a prefab wall panel having available space between the studs for the running of electrical wiring and plumbing therein. 
       BACKGROUND OF THE INVENTION 
       [0003]    Prefab wall panels, prefab roof trusses and plywood sheathing are often used to erect a house in a very short time with few workers. Prefab building components are normally preferred by the construction industry as they are assembled with approved materials, according to controlled procedures and under the ideal conditions of a well equipped shop. For these reasons, houses built with prefab components are generally of a better quality than conventional structures built outdoors on a construction site. 
         [0004]    An important aspect of the quality of a house is the thermal resistance of its structure. In that respect, home builder associations as well as writers of national building codes specify a minimum level of insulation to be installed in walls, ceilings and around foundations of new houses. Normally the insulation requirement for the walls of a house built in Canada for example, varies between R-16 and R-27 depending on the number of degree-days of a particular region. 
         [0005]    A typical conventional prefab wall panel having an insulation value of R-20 is built with nominal 2″.times.6″ wood framing members covered on the outside surface with panels of half-inch plywood or particleboard, half-inch fibreboard sheathing and an exterior cladding. The space between the studs is completely filled with batt type fibreglass insulation. The interior finish may comprise another half-inch fibreboard insulation and a gypsum board. This type of prefab wall panel is usually fabricated and transported to a construction site without the batt insulation, interior finish and exterior cladding. 
         [0006]    A drawback of this type of construction is the fact that each wall panel is relatively heavy to handle and erect on a floor structure. Also, the batt insulation is still installed in the usual manner, when the new building is closed-in. 
         [0007]    As alternatives to the R-20 nominal 2″.times.6″ wall structure, a number of different types of prefab wall panels are made with a solid foam core encapsulating a smaller wood frame. A first example of pre-insulated wall panel having a foam core is described in U.S. Pat. No. 4,109,436 issued on Aug. 29, 1978 to Adrien Berloty. This building panel comprises a wood frame which is completely filled with foam. The foam forms a rigid block which adheres to the frame. The continuity of the foam block in the frame give the panel a good stability as well as excellent thermal insulation. 
         [0008]    A second example of a prefab wall panel having a foam core is disclosed in the U.S. Pat. No. 4,628,650 issued on Dec. 16, 1986 to Bert A. Parker. The document describes a structural insulated panel system comprising a foam core having channels for receiving framing studs or rafters. The foam core also has an overhanging portion around its periphery for overlapping the framing members along the edges thereof. The foam core completely covers the framing members for efficiently sealing the wall from infiltration of cold air inside the building. 
         [0009]    A third example of a wall section having a foam core is illustrated and described in the U.S. Pat. No. 5,353,560 issued on Oct. 11, 1994 to John J. Heydon. This invention discloses a plurality of preformed foam blocks, wherein each block is fitted between two adjacent vertical posts of a wall section. Each block has a recess along the edge thereof for encapsulating one post and for overlapping a portion of an adjacent foam block. The plurality of interlocked foam blocks encapsulates completely all posts of a wall framing. 
         [0010]    Although a solid foam core has been preferred in the past for obtaining high insulation value with a relatively thin wall section, the foam core takes up all the hollow space between the wall studs. Sub-trade workers such as electricians and plumbers must use hot knives for cutting grooves through the foam core for running plumbing piping and manifolds or an electrical system into the insulated wall section. 
         [0011]    For this reason, the work saved by carpenters for erecting a foam filled wall structure is often offset by the additional manpower required by sub-trade workers for grooving the insulation. Hence, a need exists in the industry for a pre-insulated prefab wall panel offering excellent thermal resistance as well as being structurally compatible to the requirement of all tradesmen involved in the construction of a building. 
         [0012]    Another example if Canadian Pat. No. 1180528 is a structural log-like member for use in constructing walls, having an outer wooden wall and an inner wooden wall. Wooden spacer members connect the inner and outer walls together in spaced-apart parallel fashion. The spaces between the walls and spacer members can be filled with an insulation material. In use, the structural members can be stacked one on top of the other to form a wall. 
         [0013]    Considering the state of the art presented above, it remains highly desirable to be provided with new prefab wall structures with insulating elements 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    One aim of the present invention is to provide a prefab wall structure comprising; 
         [0000]    a. two opposite first and second side wall boards;
 
b. a stud assembly comprising at least a first and second stud member between the two opposite side wall boards, the first stud member being secured with first side wall board, the second stud member being secured with the second side wall board, the first and second stud members being in contact one to the other to form a surface of contact, the surface of contact being non parallel to the first and second wall boards, thereby defining with said first and second wall boards and a plurality of stud assembly a plurality of cavities, wherein each cavity has a depth higher to a thickness of each of the stud member, and has a depth equivalent to the thickness of the stud assembly.
 
         [0015]    Another aim of the present invention is to provide a prefab wall structure comprising a stud assembly comprising at least a first and second stud member between the two opposite side wall boards, the first stud member being secured with first side wall board, the second stud member being secured with the second side wall board, the first and second stud members being in contact one to the other to form a surface of contact, the surface of contact being non parallel to the first and second wall boards, thereby defining with the first and second wall boards and a plurality of stud assembly a plurality of cavities, wherein each cavity has a depth higher to a thickness of each of the stud member, and has a depth equivalent to the thickness of the stud assembly. 
         [0016]    In accordance with the present invention there is provided a method of manufacturing a prefab wall structure comprising the steps of: 
         [0017]    fixing a stud member on a wall board to form a first prewall structure; 
         [0018]    assembling the first prewall structure to a second prevail struture by securing the stud member of a first prewall structure with the stud member of second prewall structure, the studs secured together forming a stud assembly, in manner to obtain a prefab wall structure, thereby defining with the wall boards of the first and second prewall structures and a plurality of stud assembly a plurality of cavities, wherein each cavity has a depth higher to a thickness of each of the stud member, and has a depth equivalent to the thickness of the stud assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a cross section of two prefab wall panels before assembling ( 1   a ) and after assembling ( 1   b ) of the preferred embodiment; 
           [0020]      FIG. 2  is a cross section of two prefab wall panels before assembling ( 2   a ) and forming a corner section after assembling ( 2   b ); and 
           [0021]      FIG. 3  illustrates a enlargement of the gap between the ends of two prefab wall panels. 
       
    
    
       [0022]    It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0024]    Referring to  FIG. 1 , the prefab wall structure  8  of the preferred embodiment has a wood structure made of nominal 2″×4″ members. The structure comprises vertical studs  10  spaced at 16″ intervals, and which can be fixed to top and bottom rail members. The prefab wall of the preferred embodiment, as is illustrated in  FIG. 1   a  can be of different length, varying from for example, but not limited to, 2 to 16 ft., and a wood frame height of 95¾″, measured between the top rail and bottom rail. The studs are covered by panels  14  and  16 , normally made of gypsum, or of wood, or any other material well known in the art. The studs  10 ,  11 ,  12  and  13  are in contact by one longitudinal surface  20  with a panel, the other surfaces remaining free into the space  24  formed between panels  14  and  16 . A stud  10  in contact with one panel is in a non-longitudinal or non-continuous contact perpendicularly to the prefab wall with another stud  11  in contact with panel  16  on the prefab wall side opposite to panel  14 . More than one pair of studs  10  and  11  can be put into a prefal wall structure depending on the dimension or strength of the wall desired. Also, the studs  10  and  11  can be separated at the contact surface between each another by an insulating membrane. The studs can alternatively be in contact one to the other through a intermediate member which can be of the same or partial longitudinal length of the studs. A trap member  18  can then be put in one panel  14  or  16  before placing a third panel  26 . The panel  26  can be a finishing panel of gypsum, or an insulating foam board, or a any finishing material fixed thereon. 
         [0025]    The prefab wall structure  8  comprised of end studs  12  and  13 , which when a wall is assembled, become in contact in the same manner than studs  10  and  11 , with a gap E closed, as illustrated in  FIG. 1   b.    
         [0026]    The person skilled in the art will know that cavities  24  can remain empty, or filled up with any insulating materials known in the building and house construction field. 
         [0027]    According to another embodiment of the present invention, the prefab wall structure can be of, for example but not limited to, 1 to 5 ft, for making the wall part below a window or an aperture. 
         [0028]      FIGS. 2   a  and  2   b  show prefab wall structures  8  assembled to form a corner wall. The gap G formed between the wall structures is tightly closed after assembling. 
         [0029]    The contact configuration of the studs forming a stud assembly permits to reduce the perpendicular thermal transmission normally found with one piece studs. The thermic bridge is therefore broken as illustrated in  FIG. 3 , where the surface of contact C between the two studs is not perpendicullar to the ends  26  of the studs  12  and  13 , the thermal transmission reduction improved, while the rigidity and solidity of the wall formed of prefab wall panels of the invention are even higher than the regulatory limits established in most countries. The present prefab wall panels improve the transmission resistance of cold as well as hot temperature through the walls. 
         [0030]    The present invention will be more readily understood by referring to the following examples which are given to illustrate the invention rather than to limit its scope. 
         [0031]    While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims.