Patent Document

FIELD OF THE INVENTION 
     This invention relates to basement wall systems for buildings and to a method for constructing basement walls for a building, and more particularly to a highly moisture resistant basement wall system which facilitates quick construction. 
     BACKGROUND OF THE INVENTION 
     Basement walls for residential buildings have generally been constructed of concrete. Typically, spaced apart vertical forms are assembled at a building site, and concrete is poured into the space defined between the forms. After the concrete has been poured, it must be allowed to set or cure for a period of several days, and often as much as two weeks or even longer. Construction of a building having a poured concrete wall must be completely suspended during the time which the concrete is curing. This delay in construction is undesirable because it usually results in a delay in progress payments and/or final payment to the builder, and can often be associated with reduced profits and/or higher costs. 
     Another disadvantage with concrete basement walls is that they have a relatively high capacity for absorbing and conveying moisture through capillary action, and, as a result, basements with concrete walls tend to be damp and clammy. This problem cannot be completely overcome by providing the concrete wall with a water resistant barrier coating or layer because moisture can still be transported from the ground through the footing, and into, and through, the concrete walls. 
     A further disadvantage with concrete basement walls is that they have relatively low thermal insulating properties. As a result, conventional basements having concrete walls tend to be relatively cool and generally uncomfortable during the winter months. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved basement wall system and method for constructing a basement wall of a building, which overcomes the disadvantages of conventional concrete walls. In particular, the basement wall system of the present invention is ready for framing the day after installation, and thus allows relatively rapid construction. A further advantage is that the basement wall systems of the present invention are highly moisture resistant and thus provide a drier and more comfortable basement. Further, the basement walls of the present invention can be easily provided with external and/or internal insulative layers to achieve good insulative properties and provide a basement which is warmer and more comfortable during the winter months. 
     These and other advantages are achieved with a basement wall comprising a plurality of spaced apart metal studs extending vertically upwardly from a sill, and metal decking secured to the plurality of studs, the studs and decking defining the basement wall. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a basement wall of a building constructed in accordance with the principles of this invention; 
     FIG. 2 is an elevational view, in partial cross-section, of the basement wall shown in FIG. 1, as viewed along lines II—II; 
     FIG. 3 is a fragmentary, elevational view, in partial cross-section, of a daylight wall of the basement wall system shown in FIG. 1, as viewed along lines III—III; 
     FIG. 4 is a fragmentary, elevational view, in partial cross-section, of a brick ledge wall in accordance with the principles of the present invention; and 
     FIG. 5 is a perspective view of a prefabricated section of a basement wall in accordance with the principles of this invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A basement wall construction  10  in accordance with the principles of this invention is shown in FIG. 1. A full basement wall  11  is shown in FIG. 2 erected on a footing  12  within an excavation, i.e., below ground level  14 . Footing  12  is comprised of compacted pea stones (i.e., stones having a size about equal to or smaller than the size of peas), but can be a conventional concrete footing if desired. In accordance with a preferred aspect of the invention, the wall is transported to the construction site and erected in preassembled sections, for example in 10 to 40 foot long sections which can be easily transported such as on a conventional flatbed trailer. 
     As shown in FIG. 5, the prefabricated sections include a metal sill or base  16 , a plurality of vertical studs or columns  20 , and metal decking  22 . Sill  16  has a U-shape channel configuration defining a horizontal base portion  24 , an outside vertical flange portion  26 , and an inside vertical flange portion  28 . Vertical studs  20  are configured to include a web portion  30  which extends along a vertical plane transverse to the length of the basement wall, an outside flange  32  which extends along a plane transverse to the plane of the web, and an inside flange  34  which extends along a plane transverse to the plane of the web. The thickness of studs  20 , as measured from the outwardly facing side of flange  32  to the inwardly facing side of flange  34 , is approximately equal to the distance between the inwardly facing side of outside flange portion  26  and the outwardly facing side of inside flange portion  28  of sill  16 , whereby the lower ends of studs  20  fit snugly between the flange portions of sill  16 . 
     Studs  20  are fixed to sill  16 , preferably by welding, such as along the lower edge  36  of web  30  which abuts against base portion  24  of sill  16 , and/or at the upper edges  38 ,  40  of flange portions  26 ,  28  which abut against the outwardly facing side of flange  32  and the inwardly facing side of flange  34  of studs  20  respectively. Metal decking  22  is secured to studs  30 , preferably with fasteners  42 , such as screw fasteners or rivets. 
     Sill  16 , studs  20 , and decking  22  are preferably made of high construction-grade galvanized steel, although other materials having suitable structural integrity and corrosion resistance may be used. It is also desirable to coat, such as by spraying, all welds with a rust inhibitor. Because the lower portions of a basement wall are somewhat more likely to come in contact with water, the lower portions of the prefabricated sections (as shown in FIG. 5) are preferably provided with a water-resistant coating. For example, after a preassembled section, such as that shown in FIG. 5, is assembled, it may be dipped into a liquid asphalt solution that coats, for example, the bottom 6 inches of the preassembled wall section. The liquid asphalt solution will dry into a high gloss water resistant shell or coating  42  (FIG. 2) which covers and seals sill  16  and the lower portion of studs  20  below line  44  (FIG. 2) to prevent moisture from contacting the metal surfaces of sill  16  and the lower portions of studs  20 . 
     The prefabricated wall sections as described above are transported to a construction site and positioned on a suitable footing  12 , with the ends of each wall section abutting an adjacent wall section to form a continuous basement wall. The ends of adjacent sills  16  of adjacent wall sections are preferably connected together. This can be achieved, for example, by welding the abutting edges of adjacent sills  16  along the base portions  24  and/or along the flange portions  26 ,  28 . Alternatively, it is possible to connect the sills  16  of adjacent wall sections by welding or otherwise fastening a suitable metal strap to portions of the adjacent sills, such as with screws or rivets. 
     In order to enhance the water resistance of the basement walls, and particularly to prevent or inhibit water leakage between the lower portion of the basement walls and the concrete floor of the basement, the sill  16  is preferably wrapped in a waterproof membrane  46  which extends continuously along the outwardly facing side of flange portion  26 , the underside of base portion  24  and the inwardly facing side of flange portion  28 . The waterproof membrane gives the wall a waterproof bottom surface and a side surface to bond with a foam membrane  50 . Suitable waterproof membranes include elastomeric membranes, such as those comprised of natural or synthetic rubber. The thickness of the waterproof membrane is -not particularly critical. However, a suitable thickness for waterproof membrane  46  is, for example, 60 mils. 
     In many, if not most, cases it may be necessary to brace the walls over the footing until the concrete floor  49  of the basement is poured. Once the concrete floor  49  has been poured, and has set, the basement walls become locked in place, and the bracing, if any, may be removed. 
     As illustrated in FIG. 2, basement wall  10  is provided with an exterior polymeric foam coating  50 . The polymeric foam layer  50  is suitably applied in liquid form and expands after it is applied to the outwardly facing surface of decking  22 . Desirably, the foam is applied after the basement wall sections have been abuttingly positioned on footing  12  to provide a seamless membrane or layer around the foundation that both chemically and mechanically bonds to the steel and footing. A suitable foam material which may be applied in liquid form and which expands up to 30 times after it is applied to the outwardly facing side of decking  22  is sold by Foam Enterprises, Inc., Minneapolis, Minn., under the product designation “FE 303-2.0 HC”. The FE 303-2.0 HC spray foam when applied to achieve a final foam thickness of approximately 1 inch provides a basement wall which has an insulation rating of R-7. Additionally, if desired, the space between studs  20  on the interior side of decking  22  may be filled with additional insulation, such as additional foam insulation or glass fiber batt. 
     Generally, within one day after the wall sections comprising sills  16 , studs  20  and metal decking  22  have been erected on site and concrete floor  48  has been poured, it is possible to begin framing, e.g., installing wood sill plate  52 , floor joists  54 , and rim joist  56 . 
     For full basement walls (those in which most or nearly all of the basement wall is below ground level), suitable thicknesses (distance from the outwardly facing side of flange  32  to the inwardly facing side of flange  34 ) include 6 and 8 inches, with 8 inch studs being preferred for larger residential buildings or buildings having 9 foot basements, and with the 6 inch walls being preferred for smaller residential buildings. For full basement walls, the studs are generally spaced apart by approximately 16 inches, although larger or smaller spacings can be used. 
     Shown in FIG. 3 is a daylight wall  57  comprising a lower section which is generally intended to be below ground level  14  and an upper section which is intended to be above ground level. The lower section is generally similar to the previously described full basement walls and includes decking  22  and polymeric foam insulation layer  50 . However, the upper portion of the daylight wall includes an outer polymeric foam board such as oriented strand board (OSB) layer  58  secured to the studs and extending along the upper section of the daylight wall  57  and an expanded polystyrene (EPS) foam layer  60  secured to the polymeric foam board in a face-to-face relationship. The daylight walls have a height equal to that of the full wall, but commonly have studs spaced about 24 inches apart, although greater or smaller spacings are possible. The larger spacing of the stud for the daylight walls as compared with the full basement walls is on account of the fact that the daylight walls are expected to only carry part, usually about half, of the earth load which a full wall is expected to carry. The daylight walls are generally less expensive to make and can therefore be sold at a lower cost than the full basement walls. The daylight walls can be provided with any number of windows as desired. 
     Shown in FIG. 4 is a brick ledge basement wall  62 . The brick ledge wall is comprised of two metal studs  64  and  66  which work together like a single stud having twice the thickness of the individual studs. For example, short studs  64  and tall studs  66  can each be 4 inch thick studs which act together like an 8 inch stud. Studs  64  and  66  are connected together with their flanges abutting. Studs  64  and  66  can be secured together such as by welding, or with fasteners such as screws or rivets. Studs  64  and  66  extend upwardly from sill  16  in a manner generally identical to that described with respect to the full basement wall illustrated in FIG.  2 . As with the daylight walls, decking  22  only extends along the lower portion of brick ledge walls  62 . At the height at which the upper end of decking  22  terminates, a brick ledge  68  is secured to studs  64 ,  66  to provide a bearing surface upon which a brick facade  70  may be constructed. The use of two connected studs ( 64  and  66 ) in place of a single stud, allows one stud to carry the brick veneer  70  and the other to carry the floor and roof loads. 
     Installation of the daylight walls and brick ledge walls is substantially identical with the installation procedure described above for the full basement walls. However, with the daylight walls, the foam insulation layer  48  is only provided over the lower portion of the wall, i.e., the exterior face of decking  22 . Likewise, with the brick ledge walls, insulating layer  48  is applied to the exterior surface of decking  22 . However, it is also desirable to apply an insulating polymeric foam layer  72  along the interior side of ledge  68  as shown in FIG. 4 to provide a continuous water and thermal insulating barrier. 
     In the illustrated embodiments, installation of the basement wall system of this invention has been described with reference to erecting the basement wall system on a pea stone footing. However, a concrete footing can be used as well. In the case where a concrete footing is used, it may be desirable to eliminate the water resistant membrane  46 , and instead position an asphalt impregnated fibrous mat (such as 30# felt paper) between the concrete footing and the underside of sill  16 . 
     Although installation of the basement wall of the present invention has been described primarily with reference to the use of prefabricated wall sections which are transported to and erected at a construction site, it is of course possible to install sill  16  onto a footing and construct the wall on-site to achieve many of the advantages described herein, without departing from certain principle aspects of the invention. 
     In addition to being ready for framing the day after installation and thereby facilitating rapid construction, and providing an insulating rating of R-12, the basement walls of the invention meet the Federal Energy Star Program. Further, only limited interior basement framing is needed, also allowing quicker construction. The resulting basement defined by the basement walls of this invention provides a living room quality environment, with no ugly, half-concrete walls showing in daylight rooms. The basement walls of the invention also provide dry multi-use areas, and because the metal wall structure does not absorb or transport moisture like concrete, and includes an exterior water-resistant, insulative layer, there is no damp, clammy feel. Another advantage with the basement walls of this invention is that the completed cost is approximately 25% less than the cost of concrete basement walls. 
     While the invention has been described in detail with respect to various specific embodiments of the invention, various alternatives, modifications and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Technology Category: e