IMPROVED WEATHER RESISTANT STRUCTURE

Background of the Invention

(1) Field of the Invention The present invention relates generally to weather resistant structures and, more particularly, to a building tile for such structures formed from a glass-ceramic.

(2) Description of the Prior Art

In the late 70's, a large influx from other states and countries into Florida created a large population boom. A massive construction boom in S.W. Florida promptly followed this influx in the early 1980's. The construction boom continues to this day.

Because of the near tropical weather in Florida and its location, severe storms and hurricanes plague the region. As a result, the Florida building requirements differ from most states, and the use of terracotta or concrete building tiles has become increasingly popular.

A Duntex concrete product along with some terracotta clay products were the early available and affordably priced roofing tiles. As used herein, the term "Duntex" is used in a general sense for a non-regulated psi standard manufactured concrete roof tile. These tiles varied greatly in physical properties and easily broke during typical maintenance and service. Ih response, the market delivered higher grades of cement tiles including an interlocking extruded product made of a minimum 400 psi concrete; although the original terracotta clay and Duntex tiles remain in use.

As the finer grade and more rigid products entered the market, they were followed by new attachment methods and assorted underlayment choices. The historical methods of "mud down" applications over 30#/90# hot-mopped systems were challenged by better quality products along with different flashing specifications. In a "mud down" application, the roof system was installed by nailing a 30# felt over the roof sheathing and applying a 90# mineral surfaced roll roofing with hot asphalt. Then a mortar patty was placed on the surface and a roof tile was pressed into it.

As Hurricane Andrew revealed in 1992, this attachment method failed miserably and the roof tiles were ripped from the structures, often causing the entire structure to fail. Thereafter, the Florida building codes were amended to include specific wind-uplift requirements. These codes also set in place more stringent attachment methods. The codes also dictated the mechanically fastened and adhesive attached systems used since 1996 for designated wind zone regions in Florida.

For example, S. W. Florida is in the 140 mph zone as is Dade County (Miami). The Dade County building code has established itself as the standard for building code requirements pertaining to maximum wind expectations. Newer underlayment products are providing the market with improved moisture barriers including self-adhering (SA) membranes with self-sealing characteristics (SBS). This new construction is offering the homeowner with an opportunity for insurance premium deductions because it forms "a secondary roof." Building code changes and improvements have been spurred not just by homeowners, but also by the loss of insurance industry capacities as many insurers exited the Florida market because of huge financial loses.

One present day method of tile roofing having improved uplift resistance is the roofing attachment known in Florida as "System One". A mechanically fastened roof tile is installed in conjunction with a "System Two" upgraded underlayment product. The underlayment is an interlocking, waterproof tile that is screwed down onto battens over a self-adhering SBS modified bitumen underlayment combined with a flashing system that incorporates returns on all water-trough details with lead soakers. The specifics of current Florida building codes can be found in the Florida Building Code (Chapters 1501-1525 and adopted 1998) and in the Concrete and Clay Roof Tile Installation Manual 3 ^rd Edition (Pages 1-101 adopted June 2001), which are hereby incorporated by reference in their entirety.

Thus, there remains a need for a new and improved weather resistant structure which is sufficiently strong and dense to survive heavy winds and rain and to resist mold and mildew while, at the same time, may be formed in a variety of pleasing colors.

Summary of the Invention

The present invention is directed to an improved weather resistant structure. The structure comprising: at least 2 outer walls; a decking for supporting a roof; a deck support structure between the top of the walls and the decking; and a plurality of glass-ceramic building tiles attached to the upper surface of the decking forming the roof. In the preferred embodiment, the building tile is a glass-ceramic substrate formed from a glass prepared at an elevated temperature and crystallized at a second lower temperature, the glass-ceramic substrate being formed in at least one predetermined color by the treatment of time and temperature. The structure may further include a moisture barrier between the plurality of glass-ceramic building tiles and the decking.

In the preferred embodiment, the structure may also include at least one inner- support wall. Preferably, the decking is formed from sheathing. The sheathing may be plywood. Also, the sheathing may be between about ¹ A and ³ A inch thick. In the preferred embodiment, the deck support may also include a plurality of trusses. The plurality of trusses may be substantially spaced apart equally.

In one embodiment, the glass-ceramic substrate is formed in at least one predetermined color by the treatment of time, temperature, and partial pressure of oxygen.

Preferably, the building tile is a monolith. The porosity of the building tile may be less than about 1%. Also preferably, the bending strength of the building tile may be greater than about 100 N/mm ² when tested according to EN 100.

In a preferred embodiment, the colored building tile is substantially color through. Also, the predetermined color may be moire. The building tile may include at least one polished surface. The polished surface of the building tile may be formed by mechanical polishing. Alternatively, the polished surface of the building tile may be formed by leaving at least one surface exposed during treatment. In a preferred embodiment, the building tile may include at least one textured surface. The textured surface of the building tile may be mold-induced or process-induced.

Preferably, the moisture barrier may be rolled onto the decking. The adjacent edges of the rolled moisture barrier may be overlapped to form an overlapping joint. In the preferred embodiment, the moisture barrier is a polymeric film.

Accordingly, one aspect of the present invention is to provide an improved weather resistant structure, the structure comprising: at least 2 outer walls; a decking for supporting a roof; a deck support structure between the top of the walls and the decking; and a plurality of glass-ceramic building tiles attached to the upper surface of the decking forming the roof.

Another aspect of the present invention is to provide a building tile, the building tile comprising: a glass-ceramic substrate formed from a glass prepared at an elevated temperature and crystallized at a second lower temperature, the glass- ceramic substrate being formed in at least one predetermined color by the treatment of time and temperature.

Still another aspect of the present invention is to provide an improved weather resistant structure, the structure comprising: at least 2 outer walls; a decking for supporting a roof; a deck support structure between the top of the walls and the decking; a plurality of glass-ceramic building tiles attached to the upper surface of the decking forming the roof, the building tile comprising: a glass-ceramic substrate formed from a glass prepared at an elevated temperature and crystallized at a second lower temperature, the glass-ceramic substrate being formed in at least one predetermined color by the treatment of time and temperature; and a moisture barrier between the plurality of glass-ceramic building tiles and the decking.

These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings.

Brief Description of the Drawings

Figure 1 is a perspective view of a weather resistant structure constructed according to the present invention; Figure 2A is an enlarged view of a portion of the roof shown in Figure 1 and

Figure 2B is a cross-sectional view of the enlarged view of a portion of the roof illustrating the overlapping arrangement of the tiles;

Figure 3 is an enlarged view of the moisture barrier of the roof shown in Figure 1;

Figures 4A and 4B are illustrations of individuals glass-ceramic building tiles constructed according to the present invention; and Figure 5 is a time-temperature diagram of the process forming the glass- ceramic building tiles shown in Figures 4 A and 4B.

Description of the Preferred Embodiments

In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward," "rearward," "left," "right," "upwardly," "downwardly," and the like are words of convenience and are not to be construed as limiting terms.

Referring now to the drawings in general, and Figures 1, 2 A, and IB in particular, it should be understood that the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto. As best seen in Figure 1, a weather resistant structure, generally designated 10, is shown constructed according to the present invention. The weather resistant structure 10 includes four major sub-assemblies: at least 2 outer walls 12; a decking 14 for supporting a roof 16; a deck support structure 18 between the top of the walls 12 and the deckingl4; and a plurality of glass-ceramic building tiles 20 attached to the upper surface of the decking 14 forming the roof 16. The improved weather resistant structure may also include at least one inner-support wall 28.

The decking 14 is formed from sheathing such as plywood that is preferably between about ¹ A and ³ A inch in thickness. The deck support structure 18 includes a plurality of trusses that are substantially equally spaced apart.

In one embodiment, as seen in Figure 3, the improved weather resistant structure may also include a moisture barrier 22 between the plurality of glass- ceramic building tiles 20 and the decking 14. The moisture barrier 22 is rolled onto the decking 14 such that the adjacent edges 24 of the moisture barrier 22 overlap to form an overlapping joint 26. The moisture barrier 22 aids in preventing mold and mildew, preventing wood from rotting, preventing any and all water intrusion, and

preventing degradation of attachment compounds for coatings, moldings, and the like. Preferably, the moisture barrier is a polymeric film.

As best seen in Figures 4A and 4B, a building tile 40 is constructed according to the present invention. The building tile 40 includes a glass-ceramic substrate formed from a glass prepared at an elevated temperature and crystallized at a second lower temperature. The building tile 40 may be used in a back splash, kitchen countertops, roofing, flooring, external or internal wall coverings, or siding.

In an embodiment of the present invention, the building tile 40 is a monolith. Preferably, the porosity of the building tile 40 is less than about 1%. In the preferred embodiment, the building tile 40 has a bending strength of greater than about 100 N/mm ² when tested according to EN 100. Table 1 shows the technical data related to the present invention.

Table 1

As seen in Figure 4A, the tile may include at least one polished surface 42. The polished surface may be formed by mechanical polishing. As best seen in Figure 4B, the building tile 40 may include at least one textured surface 44. The textured surface 44 of the building tile 40 may be mold induced or process-induced. As used herein, mold induced refers to a textured surface that is created on the surface of the material due to a texture built into the mold. As used herein, process-induced refers to a texture that is created in the process that creates the glass-ceramic.

Also preferably, the building tile is substantially color through. As used herein, color through refers to the fact that the color may be on the surface of the material only, or alternatively the color may extend throughout the product. The predetermined color may have a moire surface. The color and surface condition of the wares created from fly ash based glass- ceramics, the tiles in particular, are controlled by changing the technological parameters of the production process. For instance, the color may be predetermined by the element present in the fly ash as can be seen in Table 2.

- ^" T

Table 2

Some of the elements, such as iron, silica, alumina, calcium, and titanium, for instance, are universally present in the fly ash composition, even if only in small amounts. Other elements such as manganese, zinc, and chromium are crystallization catalysts that may be inserted into the glass-ceramic to develop a specific color.

For instance, titanium, which is an effective crystallization catalyst of the glass-ceramic is in raw fly ash, but may be additionally inserted into the fly ash to produce certain colors. As seen in Table 2, the titanium can ensure the glass-ceramic coloration in a variety of colors. The same is also true for other elements presented in Table 2.

As best seen in Figure 5, there is a heat treatment curve depicting the process of the present invention. The optimal conditions for obtaining specific color or surface textures include the crystallization process that includes two stages and a cooling stage. In the first crystallization stage, the materials are exposed to a temperature between about 650 and 900° C for between about 1/4 and 6 hours. Following the first crystallization stage, the material is heated at a rate of between about 12 and 360 °C/hr. to temperature of between about 820 and 1200 ⁰ C. The second crystallization stage is characterized by exposing the materials to temperatures between about 820 and 1200 ⁰ C for between about 1/4 and 6 hours. The crystallization process is followed by a cooling stage, wherein the material is cooled at a rate of 12-360 °C/hr. to temperatures ensuring the technological process continuation.

The surface texture and color of the glass-ceramic wares can.be manipulated by changing the elements involved, the time, the partial pressure of oxygen, and/or the temperature. For instance, a shiny, smooth surface is produced by some decrease of the quantity of crystals in the glass-ceramic and by the corresponding increase of the. residual glass quantity. This can be achieved by decreasing the maximum temperature of crystallization in relation to the preferred optimal temperature. Such a change produces dark toned glass-ceramics in shades of black, dark-blue, and dark- green for example.

Lighter tones with decorative patterns can be created by progressive reducing of the crystalline phase to form marble like glasses instead of glass-ceramics.

A smooth, matte surface is obtained by forming a dense (solid) thin-dispersion (microcrystalline) structure of glass-ceramic with a maximum crystal quantity. This can be achieved by using an optimal crystallization regime by correctly selecting temperatures of the first and second crystallization steps, corresponding to the maximum crystallization centers formation and the crystals increased growth rate. This method also ensures a base color of glass-ceramic based on the oxide present in the fly ash.

The oxides in the fly ash used to produce the glass-ceramic produce certain colors as specified in Table 2: Those colors can be manipulated by raising or lowering the temperatures during crystallization. Trial and error produces lighter or darker variations of the color produced by the fly ash containing specific oxides. Thus, when creating glass-ceramic tiles, one must first determine the general color desired, and the oxide needed to achieve that color. Then trial and error can determine the proper temperature of crystallization to make the color lighter or darker as desired.

Smaller crystals typically produce stronger glass-ceramics, and as such, small crystals should be chosen for higher strength application. Alternatively, some applications may require less strength, and as such larger crystals may be formed. A rough surface is produced by increasing the crystal's dimensions in the glass-ceramic. This can be achieved by a shift of the first crystallization step temperature to the greater or lesser direction in comparison with the optimal temperature. The second crystallization step temperature should remain at the optimal temperature. In this case the glass-ceramic color usually corresponds to the base color, but can be manipulated based on the oxide present in the fly ash and the temperatures used during crystallization.

Alternatively, another method is to increase the temperature of the second crystallization step in comparison with the optimal temperature, while keeping the first crystallization step temperature at the optimal temperature. This method produces lightly toned glass-ceramic colors such as cream, yellow, etc. However, depending on the glass-ceramic composition, red, brown, or terracotta colors may be obtained.

The mechanism of the glass-ceramic color regulation is complicated. In the crystallization process there is a change in the valence state of the variable valence elements existing in the glass-ceramic composition. The surface of the product changes color because of the atmosphere of the furnace. In other words, the oxides present in the fly ash are influenced by the atmosphere of the furnace.

It is important to emphasize that in the glass-ceramic base of fly ash there are several variable valence elements. The presence of the elements increases the _ coloration options in the crystallization process. The glass-ceramic coloration by means of valence state change of the variable valence elements is defined as a diffusive process. The regulation of the atmosphere in the crystallization furnace, the temperatures and duration of the first and second stages of crystallization regime, and the heating and cooling rates make it possible to obtain a surface layer having the desired color and color depth.

Thus, for regulation of the color and surface condition of the glass-ceramic wares on the base of fly ash in the crystallization process it is necessary:

• To develop a needed atmosphere in the crystallization furnace (oxidative, reductive, or neutral)

• To carry out the crystallization regime in such a way as the temperature of the first and second crystallization stages will ensure the needed: content of the crystalline phases, crystal dimension, and the valence conditions of the variable valence elements.

Sample 1

The base fly ash used to produce the glass-ceramic of the present invention may be obtained from South African coal ash. The South African coal ash compositions are presented in Table 3.

Table 3

In order to achieve an oxidative atmosphere in the melting furnace, the unburned coal is primarily burnt out in the rotary furnace at a temperature of between about 820 and 900 ⁰ C for between about 2 and 4.5 hours. In order to achieve neutral or reductive atmosphere in the melting furnace, various quantities of burned coal ash (which was preliminarily burned) is mixed with the unburned coal ash. The quantities used vary based on the desired atmosphere in the furnace. The present invention is best understood after a review of the following examples.

Example 1; An oxidative atmosphere in the melting furnace After burning the South African coal ash, chalk ( Calcium Carbonate, CaCO ₃ ) is added in an amount of between about 16 and 20% by weight of the coal ash. Additionally, ratile (Titanium Dioxide, TiO ₂ ) is added in an amount of between about 8 and 12% by weight of the coal ash.

This mixture is then heated in a gas (LPG) melting furnace to between about 1480 and 152O ⁰ C for between about 2 and 4 hours, Wherein the gas-air ratio is approximately 1:40. Then the properly cooked glass is molded in a special form, the linear dimensions and shapes of which correspond to the customer's specifications.

The ready plates may be placed into a furnace for an annealing process with the following crystallization regimes. Alternatively, the ready plates may go directly to crystallization with the following crystallization regimes. The crystallization regimes and results are presented in Table 4.

Table 4

Example 2: A neutral atmosphere in the melting furnace First, a mixture of burned South African coal ash in an amount of about 80% by weight of the coal ash, unburned coal ash in an amount of about 20% by weight of the coal ash, chalk (Calcium Carbonate, CaCO ₃ ) in an amount of between about 16-20% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 8 and 12% by weight of the coal ash (over 100%) is formed.

This mixture is heated in a melting furnace to between about 1500 and 152O ⁰ C for about 1 hour and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 5.

Table 5

Example 3: A reductive atmosphere in the melting furnace A mixture of: burned South African coal ash in ah amount of about 50% by weight of the coal ash, unburned coal ash in an amount of about 50% by weight of the coal ash, chalk (Calcium Carbonate, CaCO ₃ ) in an amount of between about 16 and 2.0% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 8 and 12% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1500 and 152O ⁰ C for about 1 hour and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 6.

Table 6

Example 4

A mixture of burned South African coal ash in an amount of about 100% by weight of the coal ash, chalk ( Calcium Carbonate, CaCQ ₃ ) in an amount of between about 50 and 70% by weight of the coal ash (over 100%), zinc oxide (ZnO) in an amount of between about 4 and 6% by weight of the coal ash (over 100%), and chromium oxide (Cr ₂ O ₃ )Ui an amount of between about 0.7 and 1.5% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1430 and 1470 ⁰ C for between about 2 and 3 hours and is then poured

and molded into tiles. The crystallization regimes and results are presented in Table 7.

Table 7

Example 5

A mixture of: burned South African coal ash in an amount of about 100% by weight of coal ash, chalk (Calcium Carbonate, CaCOa) in an amount of between about 50 and 70% by weight of the coal ash (over

100%), zinc oxide (ZnO) in an amount of between about 4 and 6% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 15 and 20% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1400 and 142O ⁰ C for between about 2 and 3 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 8.

Table 8

0

Example 6

A mixture of: burned South African coal ash in an amount of about 100% by weight of the coal ash, chalk (Calcium Carbonate, CaCO ₃ ) in an amount of between about 50 and 70% by weight of the coal ash (over 100%), zinc sulfide (ZnS) in an amount of between about 4 and 6% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 15 and 20% by weight of the coal ash (over 100%) is heated in a melting, furnace to between about 1400 and 142O ⁰ C for between about 2 and 3 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 9.

Table 9

Example 7

A mixture of: burned South African coal ash in an amount of about 100% by weight of the coal ash, chalk (Calcium Carbonate, CaCO ₃ ) in an amount of between about 16 and 20% by weight of the coal ash (over 100%), rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 8 and 12% by weight of the coal ash (over 100%), and manganese dioxide (MnO ₂ ) in an amount of between about 0.8 and 1.2% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1480. and _. 152O ⁰ C for between about 1 and 2 hours and is then poured and molded into tiles. The. crystallization regimes and results are presented in Table

10 10.

Table 10

15

Example 8

A mixture of: burned South African coal ash in an amount of about 100% by weight of the coal ash, chalk (Calcium Carbonate, CaCOs) in an amount of between about 35 and 45% by weight of the coal ash (over 100%), rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 4 and 6% by weight of the coal ash (over 100%), and chromium oxide (Cr ₂ O ₃ ) in an amount of between about 0.4 and 0.6% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1420 and ^■ 1470°C for between about 1 and 2 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table

10 11.

Table 11

Example 9

A mixture of: burned South African coal ash in an amount of about 100% by weight of the coal ash, chalk (Calcium Carbonate, CaCO ₃ ) in an amount of between about 55 and 65% by weight of the coal ash (over 100%), and chromium oxide (Cr ₂ O ₃ ) in an amount of between about 0.8 and 1.2% by weight of the coal ash (over 100%) is heated in the a melting furnace to between about 1420 and 147O ⁰ C for between about 1 and 2 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 12. 0 Table 12

Example 10

A mixture of: burned South African coal ash in an amount of about 100% by weight of the coal ash, magnesium carbonate (MgCO ₃ ) in an amount of between about 20 and 30% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 10 and 12% by weight of the coal ash (over 100%) is heated in the a melting furnace to between about .1480 and 152O ⁰ C for between about 2 and 4 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 13.

10

Table 13

Sample 2

Alternatively, the base coal ash may be obtained from the United States. For example, the coal ash may be obtained from Tatum, Texas. The coal ash composition for that coal ash is presented in Table 14.

Table 14

Uriburned carbon is found in this particular coal ash in the amount of 0.08%.

The present invention is best understood after a review of the following examples:

Example 11 A mixture of: burned United States' coal ash from Tatum,

Texas in an amount of about 100% by weight of the coal ash, chalk

(Calcium Carbonate, CaCO ₃ ) in an amount of between aboutlO and 12% by weight of the coal ash (over 100%), and rutile (Titanium Dioxide, TiO ₂ ) in an amount of between about 10 and 11% by weight of the coal ash (over 100%) is heated in a melting furnace to between about 1480 and 152O ⁰ C for between about

2 and 4 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 15

Table 15

Sample 3

Alternatively, the base coal ash may be obtained from the United States. For example, the coal ash may be obtained from Mansfield, Louisiana. The coal ash composition is presented in Table 16.

Table 16

This particular coal ash contains unburned carbon in an amount of about

0.04%.

The present invention can be best understood by a review of the following examples: Example 12

A mixture of: unburned coal ash in an amount of about 100% by weight of the coal ash, alumina (Al ₂ O ₃ ) in an amount of between about 10 and 12% by weight of the coal ash (over 100%), chalk (Calcium Carbonate, Ca ₁ CO ₃ ) in an amount of between about 20 and 22% by weight of the coal ash (over 100%), and rutile

(Titanium Dioxide, TiO ₂ ) in an amount of between about 10 and 11% by weight of the coal ash (over 100%) is heated in the a melting furnace to between about 1480 and 152O ⁰ C for between about

2 and 4 hours and is then poured and molded into tiles. The crystallization regimes and results are presented in Table 17.

Table 17

Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, another method of 0 manipulating the color of the surface layer of the glass-ceramic is to create upon it a drawing by using materials that are burned during the process of crystallization such as paraffin or wax. The drawing may be done by a template or any other method. The material burned in the crystallization furnace creates a reductive atmosphere which locally changes the color of the glass-ceramic. Additionally, the surface layer

can be colored in an opposite way through the use of acids in order to develop the inner color in the glass-ceramic. Through covering the surface that is not to be colored with corrosion protective materials like wax or paraffin, a desired pattern may be drawn onto the surface. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.