Exterior Wall Composition

(a) Field of the Invention

The present invention relates to an exterior wall composition for building structures and a method of making same and more particularly a wall composition wherein concrete is sprayed on an inner wall membrane which is secured to a lattice framework of load bearing steel studs.

(b) Description of Prior Art

Various types of wall structures are known utilizing concrete. Some of these walls structures are formed by precast concrete slabs interconnected together and an insulating layer is then adhered to an inner face of the slabs with a finish board material secured thereover. The concrete slabs are usually held together by steel inserts provided at strategic locations or else the slabs are formed with joints which intermesh with joints of adjoining slabs to interlock. Open joints are then grouted and a seal is formed by applying a sealing compound. A disadvantage of such methods is that it is required to make the concrete slabs at a remote factory and transport these on site. Also, large machinery is required to erect the concrete component parts of the structure. A further disadvantage is that the inside finishing of such structures is complex requiring the securement of struts to set concrete. Furthermore, molds are required to make the concrete slabs.

Other concrete wall compositions are known where concrete is poured within a form which is erected on site. A disadvantage of this type of wall construction is that form work is required which is an expensive and time consuming operation. Further, an inner and/or outer finished wall must be constructed after the forms are removed once the concrete has set.

It is a feature of the present invention to provide an exterior wall composition for building structures and a method of making same which is an improvement over existing prior art concrete wall structures and methods of making same.

According to the above feature, from a broad aspect, the present invention provides an exterior wall composition for building structures, which composition comprises a lattice framework of rigid wall structural members. At least some of the wall structural members have inner and outer attachment means. An inner wall membrane is secured to at least some of the inner attachment means of the wall structure members to define an inner wall surface. A layer of insulating material is sprayed and adhered on an inward face of the inner wall membrane and between the wall structural members. A reinforcing material layer, having interstices, is secured to at least some of the outer attachment means. A layer of concrete material is sprayed on the insulating material and extends outwardly of the reinforcing material layer whereby the wall structural members are embedded between an outer wall surface of the concrete material and the inner wall membrane.

According to a further broad aspect of the present invention there is provided a method of making an exterior wall for building structures. The method comprises the steps of forming a lattice framework of rigid wall structural members and securing an inner wall membrane to an inner side of the structural members. A layer of insulating material is sprayed on an inward face of the inner wall membrane to adhere thereto. A reinforcing material layer, having interstices, is secured to an outer side of the structural members. A layer of concrete material is sprayed on the insulating material through the interstices with the layer of concrete extending outwardly of the reinforcing material layer to form an outer wall surface.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings which are examples thereof and wherein:

FIG. 1 is a cross-section view of the exterior wall composition;

FIG. 2 is a cross-section view of a modification of the wall composition of FIG. 1; and

FIG. 3 is a cross-section view of a still further modification of the wall composition of FIG. 1.

Referring now to the drawings and more particularly to FIG. 1, there is shown generally at 10 the exterior wall composition of the present invention. The wall composition comprises a lattice framework constructed from a plurality of rigid wall structural members 11, herein constituted by load bearing galvanized steel studs of generally U-shaped configuration. The studs 11 are spaced vertically along a wall every sixteen or twenty-four inches, as is customary in wooden frame building structures, whereby to receive joints of building material every four feet and to provide a securement means every sixteen or twenty-four inches. The load bearing steel studs 11 each define, in cross-section, an inner flange 12 and an outer flange 13 formed integral and interconnected by a transverse web 14. The inner and outer flanges 12 and 13 respectively, constitute attachment means, as will be described later. Although the studs are herein shown as being of U-shaped cross-section, other cross-sections are possible to provide suitable attachment means and interconnection among themselves. Also, the interconnection of the studs in the lattice framework may be done by welding, bolting or other suitable fastening means well known in the art.

An inner wall membrane 15, herein constituted by gyproc type sheeting, or other suitable material, is secured to the inner flange 12 of the studs 11. The inner wall membrane 15 has an outer finished surface 16 and an inner surface 17. The membrane 15 is secured to the flange 12 by suitable means, such as self-drilling and tapping screws 40 as shown in FIG. 2.

A layer of insulating material 18 is sprayed and adhered on the inner surface 17 of the membrane 15. The insulating material may be urethane insulation or other type insulation which can be sprayed. Alternatively, although not preferable, the insulating layer 18 may be of rigid sheet-like form and cut and attached to the inner surface 17 of the membrane 15. As shown, the insulating material extends between adjacent studs 11 in the lattice framework, where a solid wall is required.

A reinforcing material layer, herein a galvanized wire mesh 19 having interstices (openings) therein is secured over the solid wall area and attached to the outer flange 13 of the studs 11 by suitable fastening or attachment means (not shown). A first layer 20 of concrete (gunite) material 21 is sprayed onto the back face 22 of the insulating material 18 through the interstices in the galvanized wire mesh 19 and extends just beyond the wire mesh 19. Thus, the outer skin of the first layer 20 is reinforced by the galvanized wire mesh 19 to provide a reinforced outer surface to substantially prevent cracking, particularly in the area of the studs 11. After the first layer 20 is cured, a second layer 22 of concrete (gunite) material 21 is sprayed over the first layer 20. The second layer 22 of the concrete 21 includes a suitable bonding additive such as that identified by the registered trademark "Sika Top" of the Sika Company. Further, the concrete material 21 is preferably of a compressive strength of from about 3,000 p.s.i. to about 10,000 p.s.i. An outer layer 23 of stucco-type finish or painting is added to the outer surface 24 of the second layer 21 to create a desired exterior finish for the building. Further, expansion joints 25 are made in the concrete to conceal and control cracking of large concrete spans. A suitable sealing material 26 is inserted in the expansion joints 25. Preferably these expansion joints are made in alignment with some of the stud members.

As can be seen in FIG. 1 the studs 11 are embedded between the outer wall surface layer 23 or 22 and the inner wall membrane 15.

Referring now to FIG. 2, there is shown a modification of the embodiment of FIG. 1 and wherein an insulating thermal barrier membrane 41 is secured to the inner surface 17 of the membrane 15 or to the studs 11 under the membrane 15. Such a thermal barrier 41 may be provided depending on the climatic condition where the building structure is located. Also, as shown in FIG. 2, the inner flange 12 provides the attachment means for the self-drilling screws 40 which secure the inner wall membrane 15 thereto. Also, as shown the joint of the gyproc boards 15 are taped with perforated tape and jointing compound 42 is applied to conceal the joint and to form a smooth wall surface which can then be finished with either paint, wallpaper, ceramic tiles, wood panelling or whatever material is desired.

The method of making this exterior wall composition 10 does not require expert skills, uses known material and permits quick erection. To erect a building structure the floor slab is firstly poured with necessary services included therein. The exterior wall composition 10 is essentially a solid insulated concrete-steel panel assembled on site. Firstly, the basic lattice framework of load bearing steel studs 11 is shipped to the site precut to the proper lengths and assembled on site by suitable means such as welding. The steel stud lattice framework is attached to the base slab (not shown) by means of low velocity steel studs driven into the concrete with gun powder. After the lattice framework has been assembled with door, window openings, etc. the inner wall membrane 15 is secured to the inner side of the studs 11 over the area where the solid wall is required. The insulating material 18 is then sprayed over the inner surface 17 of the membrane 15 to a desired thickness depending on the insulating property required. Of course, the width of the studs 11 depends on the thickness of the wall required for the particular building structure.

The next step in the process is to secure the galvanized wire mesh 19 to the outer flange 13 of some of the studs whereby to hold the wire mesh sheet in place over the area where a solid wall is required. The first layer 20 of concrete (gunite) is applied to the desired thickness, in this particular example 21/4 inch, and is sprayed through the interstices of the wire mesh and against the backface 22 of the insulating material 18. After a curing and setting time of from about 12 to 24 hours, a second layer 22 of concrete, herein approximately 3/4 inch in thickness, is sprayed and wood-float finished onto the first layer 20. The second layer of concrete contains a chemical additive to assure a good bonding and to eliminate cracking in the final surface. Of course, under ideal climatic conditions and with suitable concrete aggregates it is possible to utilize only one concrete layer 21. An outer stucco-finish 23 may then be applied to the second finish, if desired. This outer coating 23 may also be coloured or patterned, if desired.

Of course, all suitable conduits for wiring or plumbing is installed within the lattice framework before installing the inner wall membrane 15. Additionally, the insulating thermal barrier 41 may be applied to the inner surface 17 of the membrane 15 prior to the step of spraying the urethane insulation 18, if desired.

Referring now to FIG. 3, there is shown a still further modification of the embodiment of FIG. 1 and wherein the inner wall membrane 15' is constituted by an outer layer of gyproc 15" and an inner layer 18' of rigid insulating foam material. This membrane 15' is secured by suitable fasteners to the inner flange 12 of the structural members 11 by suitable fasteners. As shown, with this type of membrane construction the structural members 11 may be of smaller width resulting in a material cost saving. Further, there is less labour content in the fabrication of the wall as the insulation layer 18' is already part of the membrane. The concrete (gunite) material 21 is sprayed in the usual manner and extends beyond the wire mesh 19. The exterior surface of the concrete wall is finished as described above with reference to the other Figure.

It is within the ambit of the present invention to provide any obvious modifications of the examples of the preferred embodiment as illustrated by FIGS. 1 and 2 herein, provided such modifications fall within the scope of the broad claims appended hereto.