US20080196336A1 - Fiber reinforced concrete exterior wall system - Google Patents

Abstract

A method of forming an exterior wall of a building, including the finished wall, includes the steps of mounting a cementitious, fiber-reinforced panel to the wall, such as the studs thereof, and then applying cementitious mortar to the panel. The cementitious mortar can be stucco, which is typically painted, or a base to which masonry units, such as stones or bricks, are mounted. The preferred panel is a glass fiber reinforced concrete panel.

Description

(e) BACKGROUND OF THE INVENTION
• 1. Field Of The Invention
• This invention relates generally to a wall on the exterior of a habitable building, and more particularly relates to a wall made of a sheet of fiber reinforced concrete combined with a mortar applied directly to the sheet.
• 2. Description Of The Related Art
• Most habitable buildings are made of vertical support members, such as wooden or metal studs or steel beams. The Support members, form a substructure to which sheets of sheathing material is attached. Typical sheathing includes plywood, oriented strand board (OSB) or some type of lightweight, insulating material, such as that sold under the trademark CELOTEX.
• The conventional method of applying a cementitious mortar, including stucco, to the exterior surface of a building, such as a house, involves many steps. Once the sheathing is in place on the building, a tar-paper or other moisture-impermeable sheet is stapled or otherwise mounted to the exterior surface of the sheathing. The next step is the attachment of a screen or wire over the paper to the sheathing to which the mortar can attach. The screen is typically stapled or nailed to the sheathing. A common problem with attaching the screen to the sheathing is securely attaching enough fasteners to keep the screen in place. Once the screen is fastened, a mortar is troweled over the screen. If the mortar is stucco, which will form the outer surface of the building, the mortar is troweled smooth, or with a pattern that forms a decorative surface. If the mortar will form the base for a plurality of masonry units, such as stone or brick, the mortar is left rough so that the stones have a subsurface to which to attach.
• The process of attaching paper, screen and mortar to the sheathing of a conventional building requires substantial skill. Mistakes by the person forming the underlying structure will permit water to infiltrate the building for many years, thereby causing cracks and large amounts of stucco or stone to fall off.
• Therefore, the need exists for a method of forming an exterior of a building that requires less skill than the conventional method, and which is less susceptible to damage from lower skilled artisans.
(f) BRIEF SUMMARY OF THE INVENTION
• The invention includes a method of forming an exterior wall of a habitable building having a substructure made of vertical support members. The method comprises mounting at least a first panel made of fiber-reinforced concrete to the substructure and then applying mortar on a first major surface of said first panel. In one embodiment of the invention, a plurality of modular masonry units, such as bricks, stones or tiles, are attached to the mortar and then mortar is injected between each of the masonry units.
• The first fiber-reinforced concrete panel is mounted in place, in a preferred embodiment, by a plurality of fasteners driven through the first panel into the substructure. A second panel made of fiber-reinforced concrete is then mounted to the substructure above the first panel by aligning a downwardly sloped lower edge of the second panel with a downwardly sloped upper edge of the first panel. It is contemplated that the joint formed between the panels can be taped or otherwise treated to reduce the appearance or function of a seam.
• The invention also contemplates an exterior wall of a habitable building. The building has a substructure made of vertical support members, and the wall comprises a first panel made of fiber-reinforced concrete mounted to the substructure and mortar mounted on a first major surface of said first panel. In a preferred embodiment, the first major surface of the first panel is a cementitious material that has a three dimensional texture.
• In another embodiment of the invention, a groove is formed in a second major surface that opposes the first major surface to permit water to drain downward. This eliminates the need for tar paper that is conventionally used with lath and conventional mortar construction.
• The invention permits stucco, stone, brick, tile and other masonry surfaces to be formed on buildings without the need to attach tar paper and screen to the sheathing of the building. Additionally, the finished product is mold-resistant due to the acidity inherent in it, much stronger than walls made with conventional sheathing materials, and less costly to form. The invention forms a vapor barrier and/or retardant, as well as a fire block, and can be used in areas where high winds are a problem.
(g) BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
• FIG. 1 is a side view illustrating a preferred panel of the present invention.
• FIG. 2 is a side view illustrating an intermediate step in a preferred installation method.
• FIG. 3 is a schematic side view illustrating a panel of the present invention in an operable position on a building wall.
• FIG. 4 is a schematic side view illustrating a panel of the present invention in an operable position on a building wall with masonry units attached to the wall.
• FIG. 5 is a schematic view in perspective illustrating a panel according to the present invention having grooves on a second major surface thereof.
• FIG. 6 is a top view illustrating part of the top of a panel that is made according to the present invention.
• In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or term similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
(h) DETAILED DESCRIPTION OF THE INVENTION
• FIG. 1 shows apanel10 that is made of glass fiber reinforced concrete (GFRC). Thepanel10 is a cementitious, fiber-reinforced material, and is preferably made of about 1-2 weight percent water reducer, about 1 percent plasticizer, about 25 percent alkali-resistant chopped glass fibers with the balance being half portland cement and half lightweight sand. The glass fibers can be the same size and shape within a particular panel, or can be made of various shapes and sizes within a particular panel. For example, in one embodiment the fibers are a mixture of lengths: three-quarters of an inch long and one and one-half inches long. Glass fibers used to form the panels can be of virtually any shape and size, as will be understood by the person having ordinary skill in the art.
• The materials are mixed together, sprayed into a mold and cured to form a sheet. The panel can be solid entirely through the thickness, or it can vary through its thickness. For example, it may be desirable to interpose an alkali-resistant scrim cloth between one face of the panel and the other face. The sheet can be a standard size, such as four feet wide by eight feet long, and between about one-quarter and one inch, and preferably about one-half or seven-sixteenths inches thick.
• Of course, other materials can be used to make thepanel10, so long as the panel is fiber-reinforced and has a cementitious surface to which a cementitious mortar can be applied. Additionally, panels of other sizes can be made, as will be recognized by the person having ordinary skill in the art. For example, a panel can be made that is the length and width of the entire side of the building. Panels can be manufactured that have window openings already formed in the appropriate areas. Still further, panels can be made that extend around corners of the building to avoid seams at building corners. Preferably, however, the panels are planar sheets of a size that can be lifted by two average men, with a maximum weight of about 100 to 200 lbs. Although the panels are preferably four feet wide by eight feet long, they can be cut to the desired shape at the construction site, such as by circular or reciprocating saws. Of course, the panels can vary from this preferred size. For example, the sheets can be much larger, and then cut to the desired size at the construction site. The panels can be smaller, such as two feet wide by four feet long.
• Once the panel is formed, it is mounted to the substructure of a building, such as a house, office building, outbuilding, commercial building, condominium or any other building that is habitable. The substructure of the typical house is made of wooden or steel Stud walls, such as those referred to as “two-by-fours”, vertically oriented to support the floor above. However, the substructure in some buildings is made of large wooden, steel or other posts or beams at corners only. The present invention can be used with any such substructure.
• Thepanel10 is attached to a substructure, such as thewall20 shown inFIG. 2, such as by drivingnails30, screws or any fasteners through the panel into thewooden studs22 of thewall20. The nails mount the panel to the substructure in the same manner that a sheet of any material conventionally used as a sheathing in any conventional building, such as OSB or plywood, is mounted to a substructure.
• Thepanel10 is rigidly mounted to thestuds22 to provide the same or better sheathing characteristics (strength, rigidity, load-bearing, etc.) as conventional sheathing materials with the added benefit of a mold-resistant and substantially fire proof panel.
• Once thepanel10 is mounted in place, asecond panel40 can be mounted above thefirst panel10 as shown inFIG. 3. Thepanels10 and40 haveedges12 and42, respectively, that are angled relative to the plane of the panel to reduce the probability that water can penetrate through the sheathing of the building. Thetop edge12 of thepanel10 is angled downwardly from the surface at thestud22 to the surface facing away from thestud22. The bottom edge42 of thepanel40 is angled in a complementary manner so that when thesecond panel40 is mounted in place above thefirst panel10, any gap between the panels has a downward slope away from the building in order to require water to flow “uphill” in order to flow into the house. Because this is essentially impossible without very high wind speeds, no water will penetrate the wall under all contemplated conditions. In one embodiment, the angle between thetop edge12 and horizontal is about thirty degrees (30°).
• Once the panels are mounted to the substructure, a layer ofcementitious mortar50 is applied to the outwardly facingmajor surfaces14 and44 of thepanels10 and40, respectively. Themajor surfaces14 and44 have a “three dimensional texture” formed on them that permits the mortar to strongly attach thereto. The term “three dimensional texture” refers to the major surface having multiple surface structures having a length and width in the plane of the panel, and a depth, measured perpendicular to the plane of the panel. A preferred texture is a repeating pattern, often referred to as “knurled”, that includes rows and columns of protruding bumps with grooves formed between each bump and the adjacent bumps. Alternatively, any shape can be used that enhances the strength with which the mortar attaches to the panel, such as the shape shown inFIG. 6.
• Themortar50 attaches directly to themajor surfaces14 and44 without the need for wires or screens to be attached to thepanels10 and40, because themajor surfaces14 and44 are made of a cementitious material. This permits the cementitious mortar to mount directly thereto. In one contemplated alternative embodiment, the major surface of a panel is made of a cementitious material, but another layer or other layers of the panel are made of a non-cementitious material. The cementitious mortar can be a stucco material that is shaped to an aesthetically pleasing contour and then painted, or the mortar can form a masonry base to which bricks, cultured stone, tile, marble or any other masonry unit can be attached. A “masonry unit” is defined herein to be any module that is commonly used to form a weather-resistant surface on a building exterior, and is attached by adhesive or mortar with other similar modules, which are then typically grouted in place by injecting mortar into gaps between the modules.
• The step of adding the masonry units includes, referring toFIG. 4, mounting the backs of theunits170,172 and174 to themortar150 applied to thepanels110 and140, which are mounted to thestuds122. Agrout180 is then injected into the gaps between the units170-174 in a conventional manner.
• In a preferred embodiment,grooves220 and230 are formed in a secondmajor surface216 of thepanel210 shown inFIG. 5, in order to form channels down which water can drain in case it penetrates through the panel, or condenses on the inside of the panel. The first major surface214 (not visible) of thepanel210 is the surface to which mortar is applied, and the secondmajor surface216 seats against the substructure of the building. Typically a house wrap or some other material is placed over the substructure before thepanel210 is mounted in place. Thus, channels are formed between thegrooves220 and230 and the wrap. If water enters the channels, it flows downwardly by gravity. The preferred channels on a four by eight panel are one-sixteenth inches thick on one inch centers across the entire back surface of the panel.
• The panel300 shown inFIG. 6 is also made according to the invention, and has a major surface302 to which the mortar mounts. The surface302 has pyramidally-shaped protuberances surrounded by grooves that permit a substantial attachment of mortar and masonry units to the panel300. The half-round grooves304 formed on the opposite major surface306 permit water drainage as described above. The surface306 seats against the wall of the building, or against a sheet product that is mounted to the frame of the building prior to installation of the panels.
• While certain preferred embodiments of the present invention have been disclosed in detail, it is to be understood that various modifications may be adopted without departing from the spirit of the invention or scope of the following claims.

Claims (14)

1. A method of forming an exterior wall of a habitable building having a substructure made of vertical support members, the method comprising:

(a) mounting at least a first panel made of fiber-reinforced concrete to the substructure; and then

(b) applying mortar on a first major surface of said first panel.

2. The method in accordance withclaim 1, further comprising attaching a plurality of modular masonry units to said mortar.

3. The method in accordance withclaim 2, further comprising injecting mortar between each of said plurality of modular masonry units.

4. The method in accordance withclaim 1, wherein the step of mounting said first panel further comprises extending a plurality of fasteners through the first panel into the substructure.

5. The method in accordance withclaim 4, further comprising mounting a second panel made of fiber-reinforced concrete to the substructure above the first panel by aligning a downwardly sloped lower edge of the second panel with a downwardly sloped upper edge of the first panel.

6. An exterior wall of a habitable building having a substructure made of vertical support members, the wall comprising:

(a) at least a first panel made of fiber-reinforced concrete mounted to the substructure; and

(b) a mortar mounted on a first major surface of said first panel.

7. The wall in accordance withclaim 6, wherein the first major surface of the first panel has a three dimensional texture.

8. The wall in accordance withclaim 6, wherein the first major surface of the first panel is a cementitious material.

9. The wall in accordance withclaim 6, further comprising a plurality of modular masonry units mounted to said mortar.

10. The wall in accordance withclaim 9, further comprising mortar interposed between each of said plurality of modular masonry units.

11. The wall in accordance withclaim 6, further comprising a plurality of fasteners extended through the first panel into the substructure.

12. The wall in accordance withclaim 11, further comprising a second panel made of fiber-reinforced concrete mounted to the substructure above the first panel, wherein the second panel has a downwardly sloped lower edge panel aligned with a downwardly sloped upper edge of the first panel.

13. The wall in accordance withclaim 12, further comprising at least one groove formed in a second major surface that opposes the first major surface.

14. A fiber-reinforced concrete panel for forming at least part of an exterior wall of a habitable building having a substructure made of vertical support members, the panel comprising:

(a) a first major surface of the first panel having a three dimensional texture;

(b) at least one groove formed in a second major surface that opposes the first major surface, said at least one groove forming a water path; and

(c) an edge of the first panel sloped from its intersection with the second major surface to its intersection with the first major surface for resisting water penetration.

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