The present disclosure relates to a roof tile attachment system and method that include the use of polymer adhesives and mechanical fasteners.
Roof tiles are widely used as roof coverings on pitched roof decks in various parts of the world. Roof tiles are extremely durable and provide significant aesthetic and decorative effects to the structures to which they are applied. Roof tiles as described herein may be made of ceramic materials and also brick, stone, concrete, clay, or plastic, wood, metal, rubber or bituminous materials.
Roof tiles have been installed using mortar or similar binders between the roof tile and a roof substrate, such as roofing felt. Using mortar is a slow procedure and labor intensive as the mortar must first be prepared, typically at ground level in buckets which must then be raised to the roof, and then the mortar is applied to the roof substrate. The mortar adds unnecessary weight to the roof. Occasionally, roof tiles are damaged during installation by dropped buckets of mortar. The set-up time of the mortar increases the time required to form the bond between the roof tile and the roof substrate. The installed roof tiles should not be moved until the mortar has set-up as movement of the roof tile affects the bond. Furthermore, the strength of the completed bond between the roof tile and the roof substrate is not extremely satisfactory. Typically, an approximate 22.7 kilogram (60 pound) load applied transversely to the roof tile will break the mortar bond between the roof tile and the roof substrate. During high wind loading conditions, such as that experienced during a hurricane or a tornado, the roof tiles frequently release from the roof structure.
In very price sensitive housing construction markets in which roof tiles are used, the conventional method of attachment of the tiles to the roof substructure is with mechanical fasteners, typically nails. The mechanical fasteners are applied at the head of each tile and the tiles are installed in an overlapping manner to facilitate covering the mechanical fasteners.
This method of attachment is economical although it has shortcomings. For example, during a wind event this method of attachment allows the “tail” or leading edge of the roof tile to lift and/or chatter causing damage in the mechanical fastener area. If severe enough and/or over time, the attachment fails and the tiles become airborne.
It is known in the art that a polyurethane adhesive may be employed to attach roof tiles to a roof substrate and to each other. This adhesive method of attachment has primarily been used in areas prone to high wind events. It has been found that adhesive-attached tiles can withstand greater “lifting” forces than mechanical fastener-attached tiles, although the installation and material cost is greater. As a result of the higher cost, the house builders of very price sensitive housing have continued to install tiles with mechanical fasteners.
It is desirable to have a roof tile attachment system and method for use in price sensitive housing construction that is able to withstand greater “lifting” forces than the conventional mechanical fastener method. It is also desirable to have a roof tile attachment system and method for upgrading an existing roof installation or repairing a roof installation to meet current code wind uplift standards. It is further desirable to have a tile attachment method that eliminates tile “chatter” during wind events.
The present invention is a roof tile attachment system and method. The roof tile attachment system and method can be used on new roof construction and on existing roofs. The roof tile attachment system and method is well-suited for use in price sensitive housing construction and is able to withstand greater “lifting” forces than the conventional mechanical fastener method of attaching roof tiles. The present invention is also suitable for upgrading an existing roof installation or repairing a roof installation to meet current code wind uplift standards. The present invention also eliminates tile “chatter” during wind events.
The objects, advantages, and features of the invention will become more apparent by reference to the drawings which are appended hereto and wherein like numerals indicate like parts and wherein an illustrated embodiment of the invention is shown, in which:
The roof tile attachment system and method, generally designated as 100, will now be described in greater detail with specific reference to the drawings. A typical roof tile, designated generally as 10, is shown in perspective view in
As shown in
The roof tiles 10 are typically installed on a pitched roof deck, designated generally as 50, as shown in
Preferably, a roofing substrate 20 forming a waterproof coating is applied and preferably bonded to the upper surface of the decking material 52. The roofing substrate 20 can be a roofing felt, commonly used in the roofing industry. The roofing felt is a roll goods membrane (
Referring to
Referring to
According to one embodiment of the present invention, during a new roof installation, a polymer adhesive 30 is preferably applied on a portion of the upper surface of the head portion 13 of the first (lower) row of roof tiles 10 on the roof deck 50. Referring to
With reference to
The present invention is also suitable for upgrading or repairing an existing tile roof system in which the roof tiles were originally installed using only mechanical fasteners. Upgrading may be necessary or desirable due to changing weather patterns, re-zoning and/or revisions to code wind uplift standards. In some instances, an insurer may require the upgrade or repair of the existing tile roof system. In other instances, a repair may be desired to eliminate roof tile “chattering” during wind events. Typically, mechanically fastened roof tiles become loose during the life of the roof system. Chattering is caused by tile movement resulting from wind lifting the nose portion 15 of an upper row of tiles from the head portion 13 of the lower row. The tiles “chatter” as they lift and fall back into contact with each other. Over a period of time, the chattering tiles may fracture at the point of attachment or further loosen the mechanical fastening of the tiles; thus, reducing the integrity of the roof system.
In this embodiment of the present invention, it is to be understood that the entire roof can be upgraded or a portion of the roof.
In this embodiment of the present invention, the nose portion 15 of the roof tile 10 is lifted, preferably in the range of 6.4 millimeters (mm) (0.25 inch) to 25 mm (1.0 inch), more preferably in the range for 6.4 mm (0.25 inch) to 19 mm (0.75 inch), and most preferably approximately 12.7 mm (0.50 inch), and the adhesive 30 is applied within the gap between the overlapping roof tiles 10. In a preferred embodiment, the adhesive 30 is applied through a small flexible tubing 32, preferably having a diameter of 6.4 mm (0.25 inch), inserted within the gap between the overlapping, lifted roof tile 10 and the underlying tile 10. The tiles 10 are brought back into contact with each other during the reactivity period of the adhesive.
It is to be understood that some portion or all of the overlapping tiles may be adhered depending on the circumstances and the desired result.
If desired, the polymer adhesive 30 can be applied in a continuous line across the width of the roof tile 10 to form a continuous barrier to the ingress of water between the overlapping rows of roof tiles. Alternatively, a nominal amount of the polymer adhesive 30 can be applied to the upper surface of the lower roof tile 10 or to the lower surface of the upper roof tile prior to installation of the upper roof tile 10. The amount of polymer adhesive 30 applied being dependent on various design criteria, including but not limited to, adhesive properties of the polymer adhesive 30, code wind uplift standards and roof tile shape.
According to one embodiment of the present invention, the polymer adhesive 30 may be a foamable or a non-foamable polymer adhesive. Preferably, the polymer adhesive 30 is a plural component, liquid polyurethane foam. The significant advantage of the plural component polyurethane foam is being able to walk on the installed roof tiles 10 shortly after the roof tiles 10 have been installed without affecting the bond between the roof tiles 10. The reactivity period or rise time of the plural component liquid polyurethane foam 30 of the present invention is preferably about one-half to about ten minutes and most preferably about one and one-half to about four minutes. It is important that the roof tile 10 be properly placed during the reactivity period to achieve the required bonding of the upper roof tile 10 to the lower roof tile 10. During the reactivity period, the liquid polyurethane foam 30 is an expanding foam, which will fill gaps and imperfections. The resulting foam provides excellent bonding between the roof tiles 10 due to the adhesive properties of the urethane. It has been found that a reactivity period of less than about one-half minute makes it difficult to timely install the roof tiles 10 during the reactivity period.
The foamable liquid polyurethane 30 is preferably a froth foam. Froth foam chemistry is well known in the art of urethane foams. The froth foam may be formed by using blowing agents such as hydrogenated chlorofluorocarbon R22 (HCFC-R22), hydrogenated fluorocarbon 134A (HFC-134A), or chlorofluorocarbon R12 (CFC-R12). Preferably, the froth foam 30 is formed by using the hydrogenated blowing agents HCFC-R22 or HFC-134A, and not CFC-R12 due to CFC-R12's reported deleterious effects to the earth's ozone layer.
Preferably, the froth foam 30 has a consistency similar to a foamy shaving cream. The froth foam is preferable over other types of foams because it can be neatly and accurately dispensed without blowing or overspraying onto other areas of the roof deck 50 or adjacently installed roof tiles 10. The preferred liquid polyurethane 30 with its shaving cream consistency does not run when placed onto a steeply pitched roof, but remains where it is installed on the roof tile 10. This ensures that the adhesive bond will be formed at the appropriate location of the roof tiles 10. Additionally, the froth foam 30 begins expanding immediately upon application and results in a firm bond between the overlapping portions of the roof tiles 10.
The liquid polyurethane 30 preferably has a density of about 0.016 to about 0.13 grams per cubic centimeter (about one to about eight pounds per cubic foot). It may be desirable to minimize the density of the liquid polyurethane 30 to minimize the weight on the roof while still providing an excellent bonding of the roof tiles 10 to each other. It has been found to be most preferable to have a foam density of about 0.024 to about 0.032 grams per cubic centimeter (about one and one-half to about two pounds per cubic foot). The application rate of the liquid polyurethane 30 is preferably about 0.45 to about 2.7 kilograms per minute (about one to about six pounds per minute) and most preferably about 0.9 to about 1.4 kilograms per minute (about two to about three pounds per minute).
The adhesive 30 is only required between a portion of the opposing overlapping tile areas to obtain the benefit. It is not intended or necessary for the adhesive to “spill over” and adhere the tiles to the roof substrate.
A test was conducted according to Southern Building Code Congress International (“SBCCI”) SSTD 11-99, Determining Wind Resistance of Clay and Concrete Tile to determine the effectiveness of the present invention. The test was run using high profile tiles, each tile installed with two screws over 2.5 centimeter×5 centimeter (1 inch×2 inch) batten strip and a 2.5 centimeter×15 centimeter (1 inch×6 inch) bead of polymer adhesive at the tile overlap. The polymer adhesive was allowed to cure. This was compared to a similarly installed tile having no polymer adhesive at the tile overlap. An eyebolt was attached to the center of the roof tile by a small hole drilled through the roof tile. An upward load was hydraulically applied transversely to the roof tile until there was a failure of the roof tile attachment. The tile with polymer adhesive achieved a resistance value of 83 Newton-meters (61 ft-lbs). whereas the tile without polymer adhesive had a resistance value of 40.4 Newton-meters (29.8 ft-lbs). The addition of the polymer adhesive resulted in a 104% increase in resistance.
It should be understood that the invention consists of a method of bonding roof tiles utilizing urethane foam and the invention should not be unduly limited to the foregoing set forth for illustrative purposes. Various modifications and alterations of the invention will be apparent to those skilled in the art without departing from the true scope of the invention.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2009/045914 | 6/2/2009 | WO | 00 | 2/18/2011 |
Number | Date | Country | |
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61057939 | Jun 2008 | US |