Abstract:
Systems and methods for modifying existing walls are disclosed. In certain embodiments, a masonry wall is constructed near an existing wall, and the cavity between the two walls is filled with a foamable, adhesive material. The foamable, adhesive material adheres to both walls, creating an adhesive connection between them. Certain embodiments create multiple layers of the foamable, adhesive material, allowing each layer to expand before the next is introduced. Certain embodiments utilize a brush device to reduce the amount of mortar left between the two walls. Certain embodiments utilize clips for temporarily securing the masonry wall to the existing wall.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/545,970, filed Oct. 11, 2011, which is hereby incorporated by reference. 
    
    
     FIELD 
     The present disclosure concerns embodiments of a construction technique that can be used for modifying existing walls. 
     BACKGROUND 
     There are many structures in need of structural reinforcement or retrofitting to provide better insulation, waterproofing, a vapor barrier, and/or aesthetic properties. In some cases these are older structures whose designs or methods of construction are inadequate in light of present engineering standards and construction methods. In other cases these are new structures under construction that could benefit from the development of new methods of reinforcing and otherwise modifying existing designs. One method that has been used to accomplish some of these aims is building a masonry veneer that is structurally tied to an existing wall. In the past, these have been anchored to the existing wall using mechanical fasteners and required the provision of an open space behind the masonry veneer to allow penetrating moisture to drain and exit at weep holes. The provision of an open space and weep holes and the use of mechanical fasteners make the structure unnecessarily complex and increase its total cost. 
     Accordingly, it would be desirable to provide methods of building masonry veneers that do not require the provision of an open space or weep holes, and that can be completed without the use of mechanical fasteners for structurally tying the veneer to the existing wall. It would also be desirable to provide methods of constructing masonry veneers that have greater strength, insulation, waterproofing, vapor-proofing, and aesthetic properties, and to do so at a lower total cost. 
     SUMMARY 
     Disclosed herein are embodiments of an invention allowing the modification of existing walls. The disclosed methods can be applied to a wall of an old house or building or to a recently constructed existing wall of a house or building under construction. In certain embodiments, a masonry wall is constructed near an existing wall, and the cavity between the two walls is filled with a foamable, adhesive material. The foamable, adhesive material adheres to both walls, creating an adhesive connection between them. Certain embodiments create multiple layers of the foamable, adhesive material, allowing each layer to expand before the next is introduced. Certain embodiments utilize a brush device to reduce the amount of mortar left between the two walls. Certain embodiments utilize clips for temporarily securing the masonry wall to the existing wall while the adhesive material is introduced into the cavity. 
     In one embodiment, a plurality of vertically stacked courses of masonry units are formed a desired distance from an existing wall, creating a cavity between the masonry and the existing wall. The uppermost course of masonry units can be secured to the existing wall using removable clips, and the cavity can be filled with a foamable, adhesive material, which is allowed to cure. Thereafter, the clips can be removed. 
     In another embodiment, a brush can be positioned along the bottom of an existing wall and can be attached to a tether connected to a fixed location above the intended top of a masonry wall. A plurality of vertically stacked courses of masonry units are formed a desired distance from the existing wall, creating a cavity between the masonry and the existing wall, with the brush at the bottom of the cavity. The tether can be used to raise the brush, removing excess mortar from the cavity. The uppermost course of masonry units can be temporarily secured to the existing wall using removable clips and the cavity can be filled with a foamable, adhesive material, which is allowed to cure. Thereafter, the clips can be removed. 
     In yet another embodiment, a bottom portion of a masonry wall can be constructed a desired distance from an existing wall. The masonry wall can be temporarily secured to the existing wall using mechanical fasteners, and a foamable, adhesive material can be introduced between the masonry and the existing wall and allowed to cure. The mechanical fasteners can then be removed, and an additional portion of masonry wall can be constructed on top of the masonry wall already adhesively secured to the existing wall. The additional portion of the masonry wall can be temporarily secured to the existing wall using mechanical fasteners and the foamable, adhesive material can be introduced between the additional portion of the masonry wall and the existing wall and allowed to cure. Thereafter, the mechanical fasteners can be removed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-4  illustrate a construction technique for constructing a veneer masonry wall adjacent an existing wall. 
         FIG. 5  is an enlarged side elevation view of one embodiment of a wall clip shown mounted on the uppermost course of a partially constructed masonry wall. 
         FIG. 6  is a top plan view of the clip shown in  FIG. 5 . 
         FIG. 7  is a front elevation view of the clip shown in  FIG. 5 . 
         FIG. 8  is an enlarged side elevation view of another embodiment of a wall clip shown mounted on the uppermost course of a partially constructed masonry wall. 
         FIG. 9  is a front elevation view of the clip shown in  FIG. 8 . 
         FIG. 10  is a top plan view of the clip shown in  FIG. 8 . 
         FIG. 11  is an enlarged view of a portion of the clip shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-4  illustrate a method for constructing a first masonry wall (e.g., wall  10 ) adjacent a second wall (e.g., wall  12 ). The method involves the use of a foamable, adhesive material to secure the first wall to the second wall. The foamable, adhesive material also serves as a vapor barrier and a waterproofing layer for the wall structure, and insulates the structure. The method has particular applicability for constructing a veneer masonry wall  10  adjacent an existing wall  12 . The existing wall  12  can be a wall of an old structure (e.g., house or building) being renovated, or a recently built wall of a new structure being built. As such, the disclosed methods can be used for constructing new wall structures or for retrofitting existing wall structures. 
     Referring to  FIG. 1 , the masonry wall  10  is constructed relative to the existing wall  12  to create a cavity C having a spacing S equal to a desired distance between the two walls. In particular embodiments, the spacing S between the walls (the width of the cavity) is at least 2 inches and can be varied as needed depending upon the particular application. The masonry wall  10  itself can constructed by laying masonry units  14  (e.g., bricks, stones, or concrete blocks) in vertically stacked courses and using mortar or grout to form the joints between adjacent units  14 , as known in the art. Each course of masonry units can comprise a plurality of masonry units placed end-to-end in a row. In other embodiments, each course of masonry units can be formed by placing the masonry units in various orientations, as known in the art. 
     As the wall  10  is constructed, a brush or gasket device  16  is placed at the very bottom of the cavity between the existing wall  12  and the first course of masonry units. The brush device  16  is connected to the lower end of a tether  18 , which can be, for example, a length of wire, rope, or string. The upper end of the tether  18  is secured at a convenient position above the wall  10  under construction, such as at a location on the existing wall  12  adjacent the upper end of the wall  12 . The brush device  16  desirably extends the length of the cavity between the two walls. The purpose of the brush device is to catch excess mortar that falls into the cavity as the mason forms the courses of the wall  10 . Additionally, after a predetermined number of courses have been formed, using the tether  18 , the mason can drag or pull the brush device  16  upwardly against the inner surface of the wall  10 , causing the brush device to brush or otherwise scrape off mortar fins (excess mortar) that extends outwardly from the joints between the masonry units  14 . The brush device collects the excess mortar and keeps the cavity substantially free of mortar fins and droppings, which can otherwise create flow paths for air or water once the adhesive material is introduced into the cavity. 
     In particular embodiments, the brush device  16  comprises a roll of fibrous material, such as felt, fiberglass netting, or polymeric fiber. The brush device  16  can comprise an internal stiffening member, such as a wooden 2×4, which is wrapped in the fibrous material. Desirably, the width of the brush device is slightly less than the width of the cavity C. As noted above, the brush device  16  desirably extends the entire length of the cavity to prevent any excess mortar from accumulating in the cavity. If the cavity is relatively long, a plurality of tethers  18  can be used to support the brush device. Each tether  18  can be spaced apart from each other along the length of the cavity C and can have a lower end secured to the brush device  16  and an upper end secured at a respective fixed location above the intended top of the masonry wall  10 . In an alternative embodiment, a plurality of brush devices  16  can be placed end-to-end along the length of the cavity, in which case each brush device can be supported by one or more respective tethers  18 . The brush device  16  eliminates the need for providing clean outs, or access openings, at the bottom of the wall to remove excess mortar. By removing mortar fins, the brush device allows for a better insulated cavity. 
     Referring to  FIG. 2 , after the predetermined number of courses have been formed, the uppermost course can be secured to the existing wall  12  using one or more fasteners, such as the illustrated clips  20 . Although only one clip  20  is shown in the drawings, a plurality of clips can be spaced along the length of the uppermost course. In particular embodiments, the clips  20  are temporary in that they are removed (and desirably can be re-used) just prior to forming the next course of masonry units  14 . The clips  20  hold the partially constructed wall  10  in place relative to the existing wall  12  as the foamable, adhesive material is introduced into the cavity, as further described below.  FIG. 2  also shows the brush device outside of the cavity after it has been used to scrape off the mortar fins on the inner surface of the partially constructed wall  10 . Typically, it is desirable to remove the brush device from the cavity before the clips  20  are installed. In a specific implementation, the wall is constructed to a height of about 6 feet to about 10 feet, with about 8 feet being a specific example, before the clips are installed. 
     Referring to  FIG. 3 , after installation of the clips  20 , the cavity can be filled with a foamable, adhesive material  22  to bond the partially constructed wall  10  to the existing wall  12 . In particular embodiments, the cavity is filled with a plurality of layers  24  of the foamable, adhesive material  22 . Desirably, the adhesive material  22  has the following characteristics: high adhesion to provide a strong bond between the walls; high compressive, tensile, and shear strength; and low expansion. The adhesive material  22  desirably is sufficiently elastic to adsorb energy transmitted to the wall structure caused by seismic activity, has a minimal set up or cure time, and produces minimal off gases harmful to those handling the adhesive material. The adhesive material  22  also may be selected to provide waterproofing for the wall structure to which the adhesive material is applied. Some examples of adhesive material that can be used include, without limitation, open or closed cell polyurethane foam, or other suitable materials. Closed cell foams are most desirable in that they are substantially impervious to water. A suitable polyurethane foam is SR Foam, a closed cell polyurethane foam available from SR Contractors (Portland, Oreg.). The adhesive material  22  desirably has a density from about 1 lb./ft. 3  to 10 lbs./ft. 3 , and even more desirably from about 2 lbs./ft. 3  to 10 lbs./ft. 3 . 
     The adhesive material can be formed by mixing a resin base material stored in a first container with a conventional activating agent stored in a second container. In one example, the base material and activating agent are mixed in a one-to-one ratio. To form polyurethane foam, such as described above, the base material would be a polyurethane resin. The base material may contain surfactants, fire retardants, a blowing agent and other additives. The density of the adhesive material  22  introduced into the cavity can be varied by starting with a base material of a different formulation, typically by varying the amount of activating agent in the formulation. 
     Pumps (not shown) in the first and second containers pump the resin base material and activating agent, respectively, through respective hoses (not shown) into a proportioning unit (not shown). The proportioning unit pumps the base material and the activating agent at about 1000 psi through respective hoses  26  to a spray gun, or nozzle,  28  wherein the base material is mixed with the activating agent. The proportioning unit and the hoses desirably have heating coils to preheat the base material and activating agent to about 120 degrees F. When the materials mix in the spray gun  28 , the activating agent triggers an exothermic chemical reaction, the product of which is the adhesive foam material  22  typically having an initial temperature of about 140 degrees F. During this early exothermic stage, the foam is in a viscous seam-like state and can be poured into the cavity. Once in the cavity the foam flows and expands to fill the cavity. 
     The nozzle  28  is moved longitudinally along the bottom of the cavity to form an even layer  24  of material of a height H. After the adhesive material is sprayed into the cavity to form the bottommost layer  24 , the end of the nozzle  28  is raised a sufficient distance so as to avoid contact with the expanding adhesive material, which is allowed to cure before another layer of adhesive material is formed on the bottommost layer  24 . Preferably, the adhesive material is cured until it expands at only a minimal rate (e.g., the adhesive material has expanded to about 99 percent of its expanded state), or more even preferably, to a point where the adhesive material no longer expands. The cure time is a function of the foam density and temperature of the foam. For example, the cure time for a foam density of 2 lbs./ft. 3  is about 4 minutes while the cure time for a foam density of 10 lbs./ft. 3  may be longer. Also, curing time increases as the temperature of the foam decreases. Once the adhesive material has substantially cured, the end of the nozzle  28  is positioned at a point just above the previously formed, bottommost layer  24  and adhesive material is sprayed on top of the bottommost layer as the nozzle is moved longitudinally of the cavity so as to form an additional layer of adhesive material. The layering process is then repeated until the cavity is filled with layers having substantially the same height H (as illustrated in  FIG. 3 ). In particular embodiments, the height H of each layer  24  is about 6 inches to about 48 inches, with about 16 inches being a specific example. Additional details regarding the foamable material  22  and the technique for forming successive layers in the cavity are provided in U.S. Pat. No. 6,662,516, which is incorporated herein by reference. 
     As shown in  FIG. 4 , a small section of the cavity adjacent the upper portion of the partially constructed wall  10  can be left empty (without any material  22 ). After forming the uppermost layer  24  of material  22 , the clips  20  can be removed from the wall and the brush device  16  can be reinserted into the cavity so as to rest on top of the uppermost layer of material  22 . The clips  20  desirably are configured to be reusable. Thereafter, additional courses of masonry units  14  can be formed to a predetermined height, the top of the partially constructed wall can be secured to the existing wall with clips  20 , and the cavity can be filled with layers of materials  22 , as previously described. This process can be repeated as needed until the wall  10  is fully formed. 
     As noted above, the material  22  bonds the masonry wall  10  to the existing wall  12 , thereby eliminating the need for conventional ties for securing the masonry wall to the existing wall. The layers of material  22  also function as a water and air barrier for the wall structure such that traditional wall waterproofing is not required. Additionally, conventional weep holes in the masonry wall are not required. Furthermore, the layers of material  22  also insulate the building. 
       FIG. 5  is an enlarged view of a clip  20  shown mounted on the uppermost course of a partially constructed wall  10 .  FIGS. 6 and 7  are top plan and elevation views, respectively, of the clip. The clip  20  in the illustrated embodiment comprises a vertical portion  40 , a horizontal portion  42 , and two leg portions  44  extending downwardly from the horizontal portion  42 . The lateral spacing between the leg portions  44  is selected to be equal to or slightly greater than the width of masonry units  14  so that the clip can be easily placed over a masonry unit and firmly engage the rear and front faces of the masonry unit. As shown in  FIG. 7 , the vertical portion  40  can be formed with a vertical slot  46  that receives one or more screws  48  that can be tightened into the existing wall  12 . 
       FIGS. 8-11  illustrate an adjustable clip  60  that can be used in the construction of the wall  10 . The clip  60  is configured to be adjustable in length to accommodate different cavity widths. The clip  60  in the illustrated embodiment includes a first wall engaging component  62  coupled to a second wall engaging component  64  by a clamping device  66 . The first wall engaging component  62  comprises a horizontal portion  68  and two leg portions  70  that engage the front and rear faces of a masonry unit  14 . The second wall engaging component  64  comprises a horizontal portion  72  and a vertical portion  74 , which is formed with a slot  76  for receiving one or more screws  48  that are screwed into the existing wall  12 . The horizontal portion  68  of the first wall engaging component can be formed with a slot  78  that receives a shaft  80  of the clamping device  66 . 
     The clamping device  66  is configured to tightly clamp and release the respective horizontal portions  68 ,  72  of the first and second wall engaging components to permit adjustment of the overall length L of the clip. When the clamping device  66  is loosened, the first and second wall engaging components can be moved relative to each other to adjust the overall length L of the clip to accommodate the width of the cavity being formed. When the clamping device is tightened, the respective horizontal portions  68 ,  72  of the first and second wall engaging components are tightly secured to each other. In this state, the overall length L of the clip  60  is fixed and the clip is effective to retain the partially constructed wall in place as the foamable material is introduced into the cavity. As best shown in  FIG. 11 , the contacting faces of the horizontal portions  68 ,  72  can be formed with teeth  82  (or similar surface features) that intermesh with each other and prevent slippage between the first and second wall engaging components. 
     As best shown in  FIG. 11 , the clamping device  66  can include a fixed nut  84  that is fixedly secured (e.g., welded) to the lower end portion of the shaft  80  and a rotatable knob  86  received on the upper portion of the shaft  80  (the knob can have internal threads that engage external threads of the shaft). An o-ring or washer  88  can be disposed on the shaft  80  between the knob  86  and the fixed nut  84 . Rotating the knob  86  in a first direction (e.g., clockwise) is effective to secure the wall engaging components to each other while rotating the knob  86  in the opposite direction (e.g., counterclockwise) is effective to loosen the clamping device and allow for adjustment of the clip&#39;s length. 
     In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. I therefore claim as my invention all that comes within the scope and spirit of these claims.