EXTERIOR ROOFING SURFACE COMPRISED OF FOAM

CLAIM OF PRIORITY

The present patent application claims priority to U.S. provisional patent application 60/717,608 filed on September 17, 2005 by inventor Wilbur Dale Mclntire and the U.S. patent application 11/348,173 filed on February 6, 2006 by inventor Wilbur Dale Mclntire, The content of these patent applications are incorporated herein by reference.

BACKGROUND

1. The Field of the Invention

This invention relates to building products and, more particularly, to an external roofing surface comprised of foam.

2. The Background

Roofing surfaces have been used since ancient times to provide a weatherproof seal to living enclosures. Two of the most common types of roofing surfaces are tiles and shingles.

Tiles are extremely popular in current construction and are commonly made of clay or cement. They have many beneficial attributes including aesthetic appeal, non- ignitability, weather resistance and longevity. However, they also have several drawbacks because they are extremely heavy and very fragile. In fact, stepping on these tiles generally creates enough stress to break them. One way of increasing their strength is by adding thickness to the tile; however this added strength comes at the cost of significantly increased weight.

The other types of common roofing surfaces are asphalt and wood shingle. Asphalt is fire resistant but provides very little additional strength to the roof, and consequently wears over time. Asphalt roofs commonly must be replaced every 10 to 15 years. Wood shingles also must be replaced because they suffer from rot and have the added detriment of not being completely fire resistant. Both of these shingle types are also very limited in their aesthetic appeal. Whereas with concrete/clay tiles you can

select non-planar shapes, shingles are generally sheet-like structures with no shape options.

Providing a weatherproof seal is a roofing surface's fundamental purpose. Roofs are generally sloped to shed rain and snow effectively. When the pitch of the roof is steep, the installation, maintenance and support of the roofing surface becomes an issue. Workmen may step on the roofing surface during construction or repairs, so the strength of the tiles is a major concern. The tiles often have a weak point at the overlap regions or at their unsupported centers. Breaking tiles effectively defeats the fundamental purpose of a roof by exposing the interior of the structure to water. Thus, the roofing surface must be strong and durable.

Strength is also important to the manufacture, shipping and handling of the roofing surface. The stronger the roofing surface material, the less will be lost due to shipping and installation breakage. But strength cannot come at the price of increased weight. The shipping cost for such weighty cargo can be significant. Also, a heavy roof requires a sizeable substructure and can be a safety hazard in an accidental roof collapse.

The porosity of roof tiles is also very important in climates with a repetitive freeze-thaw cycle. The more porous a roof surface is, the more water it will absorb. Once that water freezes, the roofing surface can split or crack, compromising the weatherproof seal. Another important feature of a roofing system is its insulation attributes. Asphalt shingles have a very low insulation rating, meaning that heat is allowed to cross the roof structure. In the winter, heat escapes the roof, while in the summer heat enters the structure. In either event, the energy costs in managing the heat transfer are significant. Therefore, a roofing system that enjoys a high insulation rating will promote significant energy savings.

A roofing system should also resist damage on the underside. Roofing surfaces often obstruct free flow of air on the underside. Air movement is beneficial because it evacuates condensation that can form on the underside, as well as any moisture that may have leaked through a crack in the roofing surface. Without ventilation, however, the moisture can begin to compromise the roof by rotting away the roofs support. When the

moisture freezes it may compromise the roofing surface by affecting the joints. Unfortunately, most conventional roof do not have sufficient ventilation.

What is needed therefore is a roofing surface that is lightweight, strong, with a high insulation rating and non-ignitable. Such a surface should also have various cross- sectional shapes to increase aesthetic appeal and finally should offer ventilation to the underside. Thus, a roofing system is provided in accordance with the invention that obtains several structural advantages, manufacturing advantages and advantages in installation.

SUMMARY OF THE INVENTION

An external roofing surface comprised of foam is disclosed. The foam is non- ignitable, very strong and extremely lightweight. The foam also resists insects including termites and carpenter ants. Various types of foam may be used; including expanded polystyrene, high density foam, Styrofoam, blue board, polystyrene, injection foams, MDI monomer, polyurethane resins, extruded foam, expanded polystyrene, expanded plastic foam, expanded polyethylene and nylon. The foam is also easily shaped by a number of shaping techniques (including hotwire, extrusion, casting, routing, punching, cutting, drilling, hand carving, infusion, laser cutting, and water jet cutting), which allows for a more aesthetically pleasing appearance and can be used to make a roofing system that interlocks and has channels for underside ventilation. A weatherproofing treatment is applied to the foam. This treatment may be inherent to the manufacturing of the foam itself. The treatment may also optionally include a reinforcement material to increase the strength and durability. These materials may be applied internally and externally and may include fiberglass mesh, shopped fiberglass, polypropylene fibers, metal mesh, polyurethane mesh, nylon mesh, and polymers. The treatment may also optionally include a coating material to impart a desired strength, durability and/or aesthetic look. Coating materials may include paint, cement, concrete, polyurethane, vinyl, latex, oil, metal, epoxy, plastic and copolymers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross-sectional view and overall view of a novel foam tile with an interlocking area. FIG. 2 depicts a cross-sectional view and overall view of a novel foam tile.

FIG. 3 depicts a cross-sectional view and overall view of a novel foam tile with an interlocking area.

FIG. 4 depicts a cross-sectional view and overall view of a novel foam ridge cap tile.

FIG. 5 depicts a cross-sectional view and overall view of a novel foam ridge cap tile.

DETAILED DESCRIPTION An external roofing surface comprised of foam is disclosed and overcomes the deficiencies that mar conventional roofing systems. The foam is non-ignitable, insect resistance, very strong and extremely lightweight. One embodiment of the external roofing surface is comprised of expanded polystyrene (EPS). EPS is generally produced from a mixture of about 95% polystyrene and 5% gaseous blowing agent (e.g. pentane). The solid plastic can be expanded into a foam by using heat, usually steam. During the pre-expansion, steam softens the plastic resin causing the pentane to expand the plastic into beads at least 100 times their original size. As long as the plastic is exposed to steam, the pentane expands enlarging the size of the beads by filling the voids with trapped air. Before all of the pentane is displaced by air, the pre-expanded bead is then placed into a mold of any shape or block that can be easily cut. Polystrene can also be extruded and is commonly known by the trade name Styrofoam®.

The foam can be manufactured such that the surface is treated to be weatherproof - i.e., the ability to withstand exposure to weather without damage. For example, the foam may be extruded, cast or laser cut (as described below), which may result in a smooth surface that may be inherently weatherproof. Or, as described below, materials

can optionally be added internally or externally to the foam, which may increase the foam's strength and water resistance.

The large void space makes EPS foam very lightweight and thus requires much less rigid structural supports. This, in turn, reduces construction costs and saves valuable lumber. The foam also will not ignite. The combination of the light weight and non- ignitability allows someone additional time to exit a burning building without fear of the roof caving in as it may in the case of heavier clay and concrete roofing tiles.

An added advantage of EPS is that it is an exceptionally good insulation material. Because the foam generally consists of airfilled pockets - in some instances 0.2 - 0.5 mm across with polystyrene walls about 0.001mm thick - the polystyrene walls occupy only about 2% of the total volume. Air is a very poor conductor of heat, thus little heat can move through the EPS structure. The roof therefore acts as an insulator that cuts down on construction costs (less insulation needed elsewhere, smaller heating and air conditioning equipment, etc.) and cuts down on the buildings energy costs. EPS also creates a tile that is much more durable than conventional materials. In comparison to clay tiles that are very brittle and will break during shipment and installation, a foam-based tile can be dropped on the ground and stepped on without damaging it. Because it is so lightweight, it is easier to handle, install and does not pose the danger of accidental injury from a falling tile. EPS is also weather and insect resistant and does not wear as easily as other convention roofing materials.

While the foam has been described as comprised of EPS, other types of foam would be apparent to those skilled in the art. Those foams include high density foam, Styrofoam®, blue board, polystyrene, injection foams, MDI monomer, polyurethane resins, extruded foam, expanded polystyrene, expanded plastic foam, expanded polyethylene and nylon.

SHAPING THE FOAM

In one embodiment of the roofing surface, a roofing tile is constructed of EPS. This type of foam can be purchased in large blocks that measure 49"W x 37"H x 96"L. The block is cut and shaped to size by using a computer assisted cutting machine. Before cutting however, the precise cuts must be programmed into the computer. For the shape

depicted in FIG. 1, the cross sectional shape 5 is programmed into the computer first. The block is then placed on the computer assisted cutting machine, in this case hot wire, which cuts the block into several tiles that are 96" long. To assist in shipping, handling and installation, the 96" long tiles are further cut into 18" sections by the computer assisted machine.

In another method of shaping, the foam is extruded into the desired shape. For example, again referencing FIG. 1, the foam can be extruded through a die that yields the cross-sectional shape 5. This is advantageous because it negates the first shaping step described above and cuts down on wasted material. The extruded foam block, with the desired cross-sectional area, could further be separated into the desired sections (i.e., 18" in the embodiment above). This can be accomplished by interrupting extrusion when the desired length is achieved, or by cutting the extruded foam to the desired length by any of the shaping methods described herein.

In yet another shaping method embodiment, the foam can be cast into the desired shape. By injecting the foam, which is still in an unhardened state, into a preformed cast, no other shaping methods may be necessary. This again cuts down on material waste.

These shaping techniques can be used to provide channels on the underside of the tile that promote ventilation. For example, the foam can be extruded in the shape depicted in FIG. 1, which shows a ventilation channel 10. The channel may reduce the amount of condensation on the underside of the roof, which will cut down on the deleterious effects of condensation. Examples of other cross sectional shapes are shown in FIGS. 2 to 5.

These shaping techniques can also be used to provide reinforcement structures such as ribs, ridges and channels. FIG. 1 depicts ridges 15 and channels 20 that add strength and aesthetics. The shaping technique employed can also be used to preferentially shape more foam on areas that need more strength, such as the unions between tiles where conventional tiles often fail. FIG. 2 depicts a tile that has more foam placed on the top of the arch 35.

These shaping techniques can also be used to manufacture interlocking tiles. For example, the tiles may have appropriate ridges, channels and fastening points to allow the interlocking of successive rows of roof tile, with the bottom edge of each row

overlapping the top edge of a lower row along the line. Tile shaped and installed in this layout produce an effective moisture barrier and an aesthetically pleasing appearance. For example, FIG. 1 depicts an interlocking area 25 that would mate with interlocking area 30. FIG. 3 also has a similar interlocking feature where area 40 mates with are 45. While the shaping of the tiles is described with reference to a computer-assisted hotwire, extrusion and casting, other shaping methods would be apparent to those skilled in the art. Those methods may include, but are not limited to, routing, punching, cutting, drilling, hand carving, infusion, laser cutting, and water jet cutting. They may further include any of these methods controlled or assisted by a computer. It should also be apparent that these shaping techniques could be used to form several shapes and sizes of tiles, such as those depicted in FIGS. 1-5.

REINFORCEMENT MATERIALS AND METHODS

Generally, reinforcement can be applied internally or externally to the foam. In one embodiment of an external reinforcement material, a self-adhesive fiberglass mesh is applied to the exterior of the foam after shaping. The mesh provides added strength to the foam. Other types of mesh may also be used and would be apparent including: shopped fiberglass mesh, polypropylene fiber mesh, metal mesh, polyurethane mesh, nylon mesh, and polymer-based mesh. Non-mesh materials may also be applied to the exterior of the foam. For example, the copolymer known in the trade as Elotex FX2320 may be appropriate. It is a redispersible binder based on a copolymer of ethylene and vinyl acetate. In the cured state, this polymer has a high strength, has an excellent freeze-thaw cycling resistance, is very flexible and impact resistant. It also adheres very strongly to foam. Reinforcement applied internally may also increase strength. Introducing nylon or fiberglass fibers to the foam prior to curing. Adding co-polymers and plastics to the non-cured foam may also strengthen it. In yet another embodiment, adding a fiberglass mesh that is imbedded in the foam provides added strength. Of course several other types of embedded structures may be used; including shopped fiberglass, polypropylene fibers, metal mesh, polyurethane mesh and nylon mesh.

While reinforcement is described with reference to above embodiments, other reinforcement materials and methods would be apparent to those skilled in the art. Instead of applying a certain material (or in conjunction therewith), structural modifications can also be used for reinforcement. Ridges, ribs or channels may be introduced to the foam structure of the roofing tile such that forces applied to the surface of the tile are more effectively balanced. Additional foam may be added to areas on the tile that may need more strength, such as the union between tiles where conventional tiles often fail. Alternatively or in conjunction, additional reinforcement material may be added to the areas that require more strength.

COATING MATERIALS AND METHODS

A coating may optionally be applied to the surface of the foam and may serve one or more of the following general attributes: appearance, protection, and strength. Specific attributes may include high compressive and tensile strength, corrosion resistance, temperature durability, inertness and colorfastness. The coating material may also serve the function of the reinforcement materials discussed above.

In an embodiment, the coating may be made from a cement mixture. Specifically, the mixture comprises: cement, sand, pigment, water, water reducer and an acrylic- bonding agent. The mixture is prepared and applied to the surface of the tile. The mixture is then dried, so as to harden it and affix it to the foam. This drying may simply be done at room temperature or by exposing the coating to heat. It is also important to note that depending on the coating material, drying may not be necessary.

Another coating material known by the trade name "Blue Eagle Brand Eaglebond" available from Eagle Building Materials at 1407 N. Clark, Freson, CA 93703-3615. This material is a proprietary blend of cement modified with redispersible powders, copolymers and inert aggregate. This coating is mixed as per the instructions of the vendor and applied to the foam. The vendor further recommends a curing time of at least 24 hours before performing any further work.

The coating may optionally be comprised of a copolymer agent such as Elotex FX2320 described above.

Elotex also makes sealing and waterproofing agents that may optionally be used. SEAL 80, as it is known in the trade, is a redispersible, silane based waterproofing agent. It may be used alone or mixed with the cement coating already described and is very hydrophobic such that it repels water. Several other coatings would be apparent to those of ordinary skill in the art, such as, materials that may strengthen, protect and/or improve the appearance of the foam. These coating may include paint, cement, concrete, polyurethane, vinyl, latex, oil, metal, epoxy, plastic and copolymers. These coating may also be a sheathing structure such as metal, plastic, and natural rock. In some cases it may be favorable to coat the entire tile. For example, where condensation may collect on the interior surface of the tile, a coating material may help protect the integrity of the foam. Another alternative is to apply the coating to only the surface of the foam that will be exposed to the elements. Or, different coatings may be applied to different surfaces to optimize the resilience of the tile. For example, a less durable coating may be applied to surfaces that are not exposed to the elements, while a more durable coating is applied to the surface that is exposed. Also, layers of coatings may be used. Various implementations would be obvious to one skilled in the art.

Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the following claims.