Abstract:
A method of adhering roof tiles to a roof utilizes a one-component adhesive and in particular, a one-component polyurethane adhesive foam applied to the undersurfaces of the roof tiles in a discontinuous patterns. The adhesive is applied in the form of separate deposits at opposing corners of the undersurfaces of the roof tiles and the roof tiles are laid on the roof in serial fashion and overlapping courses.

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of prior U.S. application Ser. No. 08/649,450, filed May 17, 1996 now U.S. Pat. No. 5,895,536. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to methods of roof construction, and more particularly relates to an improved method for adhering roof tiles to substrates using economical one-component adhesives, including one-component high-density polyurethane adhesive foams. 
     Roof construction, especially in residential construction, varies by location throughout the United States. In the northern climates, most roofs utilize a thin covering of tar paper-based shingles or thick wooden shingles as a final covering for the roof. In southern climates, tiles are used as the final covering of the roof. These roof tiles may be made from a variety of materials, including synthetic materials, such as plastics, and natural materials, such as stone, concrete, clay, ceramic and fired brick. In the application of these latter types of roof tiles, mortars or cementitious materials have been used in the past to apply the roof tiles to the roof substrate. 
     The use of mortars as roof tile adhesives is expensive because the mixing and application of the mortar is very labor intensive. Mortars are dense materials and their use as roof adhesives increases the load placed on the roof. The curing time for mortar may also be relatively long, thereby hampering quick completion of the roof. A need therefore exists for a lighter adhesive which is less labor intensive than mortar and which lends itself to efficient application of roof tiles. 
     Adhesives, and in particular adhesive foams, have been developed to replace mortars used in roof construction. U.S. Pat. No. 5,362,342, issued Nov. 8, 1994 describes the use of a two-component polyurethane foam to bond roof tiles to a substrate. This patent further describes the use of a bulky, complex pressurized dispensing system which is necessary to mix the two components together so that they may react to create a sufficient amount of foam with the desired adhesive characteristics. The aforesaid &#39;342 patent further describes a particular method of using two-component foams to bond roof tiles to a roof substrate in which thick, linear beads of foam are applied to the entire length of the roof tiles. 
     One-component adhesives, such as those sold under the trade name INSTA-STIK by Insta-Foam of Joliet, Illinois have been utilized in the past, primarily for adhering roof insulation boards to roof substrates. These one-component adhesives are collapsible foams and are applied in long beads of foam for all or most of the entire length of the insulation boards to adhere the insulation boards to the roof. The use of long, linear beads of adhesives increases the cost of applications by using large amounts of adhesives and lengthening the application process. 
     The present invention is directed to a roof tile adhesion method which uses inexpensive one-component adhesives, and in a preferred embodiment one-component polyurethane adhesive foams, in a novel application pattern which significantly reduces the amount of adhesive used per roof tile without detracting from its adhesive strength. 
     It is therefore an object of the present invention to provide a method of adhering roof tiles to a roof substrate using economical one-component adhesives, including one-component adhesive foams. 
     Another object of the present invention is to provide a method for adhering roof tiles to a substrate using a modest amount of adhesive in a unique pattern which reduces the amount of adhesive used for application, yet provides sufficient adhesive strength between the roof tile and the substrate. 
     Yet another object of the present invention is to provide a method for adhering roof tiles to a substrate by applying a one-component, high-density polyurethane adhesive foam to opposing corners of the roof tile and placing the tiles into contact with the substrate, and letting the adhesive foam cure to adhere the roof tile to the substrate. 
     Still yet another object of the present invention is to provide an improved tiled roof construction having a substrate, a plurality of roof tiles adhered to the substrate, the roof tiles being adhered to the substrate by an adhesive deposited in alignment with opposing corners of the roof tiles, the adhesive deposits having a pad-like profile, the adhesive pads adhering opposite corners of the tile to the roof substrate and a preceding tile course, the adhesive pads further defining a discontinuous adhesive pattern which does not subdivide the space between the tile undersurfaces and the roof substrate into discrete spaces to restrict air circulation between the roof tile and the roof substrate. 
     SUMMARY OF THE INVENTION 
     In one principal aspect of the present invention, a roof construction method is provided in which successive courses of roof tile are adhered to a roof substrate by applying a one-component adhesive to the undersurface of the roof tiles; laying the tiles in successive courses on the roof; and, permitting the foam to cure. 
     In another principal aspect of the present invention and as exemplified in one preferred embodiment, a method for applying roof tiles to a roof substrate is provided which includes the steps of: providing a one-component adhesive, particularly a one-component adhesive foam; applying a first course of roof tile to a roof substrate by depositing the adhesive in a discontinuous pattern comprising two separate deposits in registration with opposite corners of the roof tiles; adhering the first course of roof tiles to the roof substrate by placing the first course of roof tiles onto the roof substrate to effect contact between the adhesive deposits, the roof tiles and the roof substrate; dispensing a series of second deposits of the adhesive in registration with opposite corners of the undersurfaces of a second course of roof tiles; placing the second course of roof tiles over the roof substrate and the first course of roof tiles such that the tail portions thereof and adhesive deposits aligned therewith contact the roof substrate and the head portions thereof and adhesive deposits aligned therewith overlie and contact the first course of roof tiles; and, permitting the adhesive to cure such that the first and second roof tile courses become adhered to roof substrate. 
     In another principal aspect of the present invention and as exemplified by another embodiment of the invention, a roof construction includes a roof substrate and a plurality of roof tiles attached to the substrate in successive courses, each of the tiles being attached to the roof substrate by discontinuous deposits of a one-component adhesive aligned with opposing corners of the undersurfaces of roof tiles, the adhesive foam deposits spacing the tiles partially away from the roof substrate so as to create an air channel therebetween. 
     These and other objects, features and advantages of the present invention will be apparent through a reading of the following detailed description, taken in conjunction with accompanying drawings, wherein like reference numerals refer to like parts. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the course of the description, reference will be made to the attached drawings in which: 
     FIG. 1 illustrates a typical pitched roof upon which roof tiles are attached; 
     FIG. 2 is a perspective view of a segment of a prior art roof construction utilizing a two-component adhesive foam to adhere a roof tile course to a roof substrate using, continuous, linear beads of adhesive foam along the entire length of the roof tiles; 
     FIG. 3 is a sectional view of FIG. 2 taken along lines  3 — 3  thereof illustrating the longitudinal extent of the adhesive foam; 
     FIG. 4 is a perspective view of a section of a roof illustrating the placement of two courses of flat roof tiles installed thereon using the present invention; 
     FIG. 5 is a perspective view of a section of a roof illustrating the placement of two courses of roof tiles installed using the present invention and used with low profile, non-planar roof tiles; 
     FIG. 6 is a perspective view of a section of a roof illustrating the placement of two courses of roof tiles installed thereon using the present invention as used with S-shaped, high profile roof tiles; 
     FIG. 7 is a view of a tennis-ball like adhesive deposit used in the present invention; 
     FIG. 8 is a view of a pad-like deposit of adhesive foam used in the present invention; and 
     FIG. 9 is a cross-sectional view of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a structure  20  having a roof  22  disposed thereon at a particular angle, or pitch P. The roof  22  includes a substrate  23  is supported on the structure  20  by a series of structural members, shown as roof joists  24  which are spaced apart from each other along the walls  26  of the structure. The roof joists  24  extend from the edge, or eave  25  of the roof upwardly at the pitch P and may be connected to a central ridge beam  28  at the apex  29  of the roof in a conventional manner. 
     The roof substrate  22  is commonly of a multiple layer construction and may include sheathing, or decking  30 , in the form of plywood, particle board, cement boards or the like which is preferably fixed to the joists  24  such as by nailing. This sheathing  30  serves as a support surface for the final covering, or cap sheet, of the roof  22 . This covering may be a water resistant material  32 , such as roofing felt or tar paper and is commonly referred to in the art as an “underlayment”. When circumstances dictate, such as when the pitch of the roof is steep, the substrate  20  may further include a series of spaced-apart batten strips  34  (shown in phantom) laterally applied to its surface to provide engagement points for anchor lugs formed in the roof tiles to engage in order to prevent movement of the roof tile during application to the substrate  22 . 
     FIGS. 2 &amp; 3 illustrate a prior art roof construction  100  which is typical of the construction described in U.S. Pat. No. 5,362,342, in which roof tiles  102  are adhered to a roof substrate  22 . As described in the &#39;342 patent, the construction  100  includes a plurality of low profile roofing tiles  102  having a Spanish-influenced design. Each roof tile  102  is rectangular in its exterior dimensions with a non-planar upper surface and has a hollow central semi-circular portion  103  flanked by two hollow quarter portions  104 ,  105  which include respective engagement edges  106 ,  107 . The central semi-circular portion  103  and its flanking quarter portions  104 ,  105  meet together to define two support ribs  110  having a flat lower surface  112  which rest upon the exposed flat surface  33  of the roof  22 . 
     As taught in the aforesaid &#39;342 patent, a two-component foam is deposited onto the exterior surface  33  of the roof  22  in the form of a thick, linear bead &#39;15 of foam. This thick bead  115  of adhesive foam extends for the entire length of the tiles  102 . In the assembly of this type of roof construction, the foam bead  115  is used to apply a starter course  120  of roof tiles, and the length of the foam bead substantially matches the length L 1  of this first course  120  of tiles. Once the first course  120  has been applied, similar thick beads  125  having lengths L 2  which match the length of the second course  126  of tiles are applied to the roof substrate  23  and the first course  120  of tiles. 
     Although the use of the two-component foam  114  in this type of roof construction  100  is effective enough to adhere the roof tiles  102  in place upon the roof  22 , such two-component foams are generally expensive. Furthermore, the teachings of the &#39;342 patent direct one skilled in the art to apply an adhesive foam bead for the entire length or substantially the entire length of the tiles  116 . This fashion of adhesive foam application promotes the use of more adhesive foam than necessary. 
     It has been discovered with the development of the present invention that a more economical one-component adhesive, including an adhesive foam, may be used to reliably adhere roof tiles to a roof substrate and in a particular pattern which uses significantly less adhesive than taught by the aforesaid &#39;342 patent and other prior art roof-adhesive foam applications. 
     In an important aspect of the present invention, a one-component adhesive is utilized to adhere the roof tiles to the roof substrate. One advantage the use of one-component adhesives, especially one-component adhesive foams, have over two-components adhesive foams is cost. Another advantage is that one-component adhesives are dispensed from single pressurized containers, which avoids the use of maintaining separate adhesive foam components by the installer on site in inventory and the need for an elaborate and complex mixing, reacting and dispensing apparatus as are utilized with two-component adhesive foams an example of which is disclosed in the aforesaid &#39;342 patent. Additionally, the methods of the present invention and, particularly the pattern used for the application of the adhesive, do not subdivide the undersurfaces of the roof tiles or the interstitial spaces between the undersurfaces and the roof substrate into discrete, areas which may inhibit the passage of air between the roof tile and the underlying roof substrate, and inhibit the opposing roof tile and substrate to grow and contract according to climatic conditions. 
     It has been found that the present invention significantly reduces the amount of adhesive needed to adhere a single roof tile to a roof substrate and further provides sufficient bonding strength to meet building code roof criteria. Table 1 which appears below in this detailed description, sets forth uplift test data for various profile roof tile using Tile Bond™ roof tile adhesive manufactured by Insta-Foam Products of Joliet, Illinois. This data indicates that the novel adhesive application pattern produces a sufficient uplift strength. 
     In another important aspect of the present invention, the one-component adhesive foam is dispensed onto the roof substrate and roof tiles in a discontinuous pattern so that the adhesive foam does not substantially subdivide the undersurfaces of each roof tile into discrete areas to thereby partially cut off air circulation as can the continuous, linear deposits of adhesive foam described in the aforesaid &#39;342 patent. The adhesive foam is further concentrated in deposits at opposing corners of the underside of the roof tile. 
     The adhesive deposits of the present invention shall be aptly characterized in this detailed description as “pads” or “pad-like” deposits because they may comprise circular or irregular shapes, rather than comprise continuous or linear, longitudinal beads. It has been found through testing, the results of which are set forth below, that such pads provides optimum adhesive strength as measured by uplift resistance force with minimal usage of the foam. The pads  50  may be generally circular in configuration and approximately the size of a tennis ball about 2½-inches in diameter D, such as is shown in FIG.  7 . The adhesive pads may also have a generally rectangular pad-like configuration  52  of dimensions of about 1 inch high by 2 inches long by 3 inches wide as shown in FIG.  8 . It shall be understood that the adhesive configurations illustrated in FIGS. 7 and 8 are merely exemplary of suitable deposits which have been demonstrated to provide the necessary uplift strength for use in roof tile attachment. Other discontinuous deposits may be utilized to achieve the same results. 
     It has also been noted that the use of these adhesive deposits in the particular pattern mentioned above not only reduces the amount of foam used, but also beneficially does not subdivide the undersurface of the roof tile and the interstitial space which occurs between the roof tile undersurfaces and the roof surface to restrict the passage of air therethrough in both the longitudinal and lateral directions (“X”,“Y”). Rather the present invention does not impart any such restrictive subdivision and thereby facilitates air passage which permits the roof substrate and tile to expand and contact harmoniously in various climatic conditions. 
     Testing of one particular adhesive, Tile Bond™ roof tile adhesive manufactured by Insta-Foam Products of Joliet, Ill., was performed on various profile roof tiles to determine the static uplift strength and moment resistance of the adhesive pattern of the present invention. This testing was performed in accordance with the Dade County (Florida) Testing Protocol PA 101-95 (JAN) “Test Procedure for Static Uplift Resistance of Mortar or Adhesive Set Tile Systems”. This Tile Bond™ adhesive in a one-component, high-density polyurethane adhesive foam. This type of foam is a minimal expanding foam and has a density which ranges from about  1{fraction (1/2+L )} pounds per cubic foot to about  4 pounds per cubic foot. The density of this adhesive foam is increased when the roof tile is passed into contact with it. Greater density foams may be used up to about 10 pounds per cubic foot. 
     The testing was performed on roof panels constructed in accordance with that described in the PA 101-95 test protocol. The roof panels had dimensions of around 4 by 8 feet upon which 14 test tiles were applied using the Insta Foam Tile Bond™ roof tile adhesive foam described above. The test sections were constructed using nominal ½ inch plywood, American Plywood Association 32/16 sheathing having a thickness of {fraction (15/32)} inches. The sheathing was nailed to 2-inch by 6-inch supports spaced at the perimeters of the sheathing and spaced on 24-inch centers in between. The nailing pattern was conventional using  8   d  (8-penny) common nails spaced on 6-inch centers along the perimeters of the panels and 12-inches within the panel. 
     An underlayment was applied to the sheathing after nailing which consisted of an ASTM D226, Type II anchor sheet with 12 gauge roofing nails and 1⅝-inch tin caps. The nailing pattern was a 12-inch grid pattern staggered in two rows of the roof panel field and 6-inch centers at any laps. An ASTM D249 mineral surface top ply sheet was attached to the anchor sheet by way of a coating of ASTM D312, Type IV asphalt and allowed to dry for 24 hours before the application of any tile systems. Thus underlayment is known in the art as a “standard 30/90” underlayment. 
     Two other underlayments were used in the tests. One underlayment consisted of a 40 mil thickness rubberized SBS modified asphalt sheet sold under the tradename Rainproof-40 by the Protectowrap Company. The other underlayment consisted of a standard two-ply 30 system using two layers of ASTM D226, Type II sheets and horizontal batten strips. These roofing sheets were lapped 19 inches over preceding sheets and mechanically attached to the roof sheathing using nails at 6-inch centers in rows of 18-inch centers. 
     A number of roof panels were constructed using the three types of underlayments described above and after the 24-hour period drying period, various profile roof tiles were attached in respective sets to each roof panel. A test hole was drilled in each of the test tiles of the panels and was located on the centerline of the roof tile at a distance of 0.76 times the length (i.e., 0.76×Length) of the tile from the head of the tile. A ¼-inch diameter concrete anchor screw was installed in this hole to provide a point on the roof tile to which a test load could be applied. 
     The tiles tested consisted of the second course of tiles, which were applied to a preceding roof tile course with a nominal 2-inch overlap. That is, the trailing edge of the roof tile was laid upon the leading edge of the preceding roof tile course. Fourteen test tiles were evaluated for each of Tests 1 through 4 on roof panels constructed using a standard 30/90 underlayment and twelve test tiles were evaluated for Tests 5 and 6 on roof panels using the rubberized SBS modified asphalt sheet and two-ply 30 system underlayments. Tile Bond™ adhesive was dispensed in a discontinuous pattern in registration with the opposite corners of the roof tiles. 
     Four different styles of roof tiles were tested from two different roof tile manufacturers. Those style tiles were the “Colonial”, “Capri” and “Espana” styles manufactured by Lifetile and the “Villa” style tile manufactured by Monier. The adhesive dispenser was weighed after adhesive was applied to every 3 to 4 tiles in order to obtain an average value of the mass of adhesive used for each tile. The adhesive was allowed to cure overnight and then the roof tiles were tested to determine their uplift resistance. 
     A floor model Instron No. 1115 testing machine equipped with a 1000 lb load cell and chart recorder was used for testing the tiles. A chain was attached between the load cell of the Instron machine and the test screw of a particular tile. The roof panels were inclined at about 9.5° to emulate a roof pitch of 2:12, that is 2-inch rise for every 12-inch of horizontal extent. The test results are reproduced in Table 1 below: 
     
       
         
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 AVERAGE 
                 AVERAGE 
                 MINIMUM 
                   
               
               
                   
                   
                   
                   
                 ADHESIVE 
                 ULTI- 
                 RESIST- 
               
               
                 TEST NUMBER 
                 NUMBER 
                   
                 ROOF 
                 AMOUNT 
                 MATE 
                 ANCE 
                 RESISTING 
               
               
                 &amp; TILE 
                 OF TILES 
                 TILE 
                 UNDERLAY- 
                 (per 
                 LOAD 
                 LOAD 
                 MOVEMENT 
               
               
                 STYLE 
                 TESTED 
                 PROFILE 
                 MENT 
                 tile) 
                 (LBS) 
                 (LBS) 
                 FT-LBS 
               
               
                   
               
             
             
               
                 1- Colonial 
                 14 
                 Flat 
                 30/90 
                 13.8 
                 143.1 
                 66.3 
                 71.1 
               
               
                 2- Capri 
                 14 
                 Low 
                 30/90 
                 12.3 
                 185.1 
                 87.3 
                 93.5 
               
               
                 3- Espana 
                 14 
                 High 
                 30/90 
                 9.8 
                 131.8 
                 60.2 
                 65.0 
               
               
                 4- Villa 
                 14 
                 Low 
                 30/90 
                 14.2 
                 223.3 
                 107.0 
                 111.2 
               
               
                 5- Colonial 
                 12 
                 Flat 
                 SBS 
                 12.8 
                 223.3 
                 106.0 
                 113.9 
               
               
                   
                   
                   
                 Modified 
               
               
                 6- Colonial 
                 12 
                 Flat 
                 2-ply 
                 11.1 
                 224.2 
                 106.4 
                 101.0 
               
               
                   
                   
                   
                 30 with 
               
               
                   
                   
                   
                 batten 
               
               
                   
                   
                   
                 strips 
               
               
                   
               
             
          
         
       
     
     It can be seen from Table 1 that the average mass of adhesive used per tile varied between about 9 grams to about 15 grams (or about 4 grams to about 8 grams per adhesive deposit), yet the least minimum ultimate load obtained was about 130 lbs as reflected in Test 3. Other testing of one component adhesives using about 2 grams per desposit have yielded uplift failure values of about 100 pounds of force. Thus, it can be seen that the discontinuous pattern of the present invention provides sufficient uplift force resistance with a substantial reduction in foam amount. 
     Turning now to FIGS. 4-7, examples of various types of roof tiles and their adhesion to a roof using the present invention are illustrated. FIG. 4 illustrates a section  400  of a pitched roof using flat profile roof tiles similar in configuration to the “Colonial” tiles of Test 1 of Table 1. The roof substrate  22  is planar and includes support sheathing  30  covered by an underlayment  32 . The roof section  400  depicted includes a lower eave  25  and the roof section  400  is angled upwardly at a preset pitch P up to a ridge  28  (shown in phantom). 
     In accordance with the present invention, a first set of roof tiles  405  is selected from a supply of tiles. The tiles  405  have opposing leading and trailing edges  406 ,  407  and side edges  408  which interconnect the leading and trailing edges  406 ,  407  together to define an overall rectangular configuration, the side edges  408  may include engagement members  410  as illustrated which permit the interconnection of adjacent ones of the first tiles  405 . A discontinuous pattern of a one-component adhesive as previously described is used for attachment of these tiles  405  to the roof substrate  22 . This pattern includes two separate adhesive deposits  420 ,  421  which are preferably aligned with each other near the opposite corners  424 ,  425  of the portions of the roof tiles  402  which oppose the roof  22  and near the leading and trailing edges  406 ,  407  thereof. The lower adhesive deposits  421  are positioned close to the eave  25  of the roof  400  on the first course tiles  405 . 
     After the adhesive deposits  420 ,  421  are applied to either to the exterior surface  33  of the underlayment  32  or directly to the undersurfaces  412  of the first course tiles  405 , the tiles  405  are placed onto the roof  400  so that contact is made between the adhesive deposits  420 ,  421 , the roof tiles  405  and the roof underlayment  32 . In this regard, the tiles  405  are preferably pushed down onto the adhesive deposits  420 ,  421  to effect a reliable contact with the underlayment  32 . The adhesive deposits do not subdivide the interstitial spaces occurring between the roof tiles and the roof substrate into discrete areas such as is taught in the aforementioned U.S. Pat. No. 5,362,342 which division would restrict air and moisture flow therebetween. Rather, the adhesive deposits  420 ,  421  beneficially do not create any such subdivision so that the passage of air (and moisture) through the interstitial spaces is facilitated rather than inhibited as illustrated in the phantom arrows of FIG.  4 . Flow of air and moisture through these interstitial areas  414  occurs as indicated by the arrows in FIGS. 4 &amp; 8, and permits the roof substrate and tiles to expand and contract in accordance with climatic conditions. 
     A second set of roof tiles  430  is then selected and the discontinuous adhesive pattern is repeated. That is, two adhesive deposits  431 ,  432  are registered with the leading and trailing edges  434 ,  435  and opposite corners  438 ,  439  of a second course of tiles  430  in locations corresponding to the corner-corner arrangement illustrated in the upper left of FIG.  4 . Once the adhesive is deposited (either on the tile themselves or the opposing roof or preceding tile surfaces), the second tiles  430  are positioned over the roof substrate  23  and the leading edges  406  of the first tiles  405  so that an overlap “O” occurs as illustrated as per the tile manufacturer&#39;s installation instructions. The second tiles  430  are then pressed down so that effective contact is made between their undersurfaces  433 , the adhesive deposits  431 ,  432 , and the roof substrate and first tile course overlap O. The second set  430  of tiles are further staggered, or offset, laterally a distance of approximately 50% of the width W of the tiles so that the interengaging side edges  436  of the tiles  430  are not aligned together in a line from the eave  25  of the roof up toward the ridge  28  of the roof  400 . 
     In FIG. 4, it can also be seen that the first set of tiles  405  which are applied at the eave  25  of the roof  22  includes a portion  410  which overhangs the eave  25 . The length of this overhang is commonly dictated by local building codes and a common overhang is in the order of 2 inches. Uplift forces may be exerted against these overhang portions  410  by high winds, and in order to provide an additional factor of safety for this first set of tiles  405  to counteract any such uplift forces, an additional adhesive deposit  422  may be applied in alignment with the remaining lower corner  426  of each of the tiles  405  of the first tile course near the trailing edges  407  thereof. 
     FIG. 5 illustrates another roof section  500  using a different profile tile. The tiles shown are a low profile tile similar to the “Capri” style tested in Test 2 of Table 1. The first course of tiles  502  have opposed leading and trailing edges  504 ,  505  and side edges  506  which interconnect the edges  504 ,  505 . The side edges  506  include interlocking strips  508  which permit adjacent tiles to be interlocked together. The first tiles  502  further have a curved exterior configuration and in this regard, the undersurfaces  510  of the tiles  502  include ribs  512  which are intended to contact the roof substrate. 
     Utilizing the present invention, two adhesive deposits  520 ,  521  are positioned in a discontinuous pattern in alignment with and near the opposing corners  524 ,  525  and leading and trailing edges  504 ,  505  of the first tiles  502 . The first tiles  502  are placed onto the substrate so that the adhesive deposits  520 ,  521  make effective contact between the substrate  23  and the tile undersurfaces  510 . A second set of tiles  530  is selected and the adhesive is either applied to those tiles  530  or to the substrate  23  and to the overlap area  532  of the first tiles  502  in the discontinuous pattern of the invention, as exemplified by the two adhesive deposits  535 ,  536  shown exposed in the upper left of FIG.  5 . The second tiles  530  are then applied onto the adhesive deposits  535 ,  536  so that the leading edges  538  of the tiles  530  oppose the roof substrate and the trailing edges  539  thereof oppose the first tiles  502 . 
     FIG. 6 illustrates another roof section  600  with a plurality of high profile S-shaped roof tiles similar in style to the “Espana” tiles tested in Test 3 of Table 1. The roof section  600  includes a first set of tiles  602  which have a non-planar configuration and S-shaped profile when viewed from either the leading edge  604  or trailing edge  606  of the tiles  602 . Side edges  606  interconnect the leading and trailing edges  604 ,  605  and preferably include engagement strips  608  disposed therealong. The first tiles  602  are applied to the roof substrate  23  near the eave  25  of the roof  600  by first applying a one-component adhesive in the corner-corner discontinuous pattern of the invention as described above. The tiles  602  illustrated typically may also include anchor lugs  607  formed on their undersurfaces to assist in retention of the tiles  602  on steeply pitched roofs. These anchor lugs  607  will typically engage a batten strip  34 . The adhesive deposits  610 ,  611  in this type application are preferably made in alignment with the opposite corners  614 ,  615  of the tiles  602  to the extent that they oppose the roof  22  and make contact on the upper end with the anchor lugs  607  and batten strips  34 . 
     A second set of tiles  620  is selected and two additional adhesive deposits  622 ,  623  are applied in alignment with opposite corners  624 ,  625  of the tiles  620 . As shown in FIG. 6, the adhesive deposits  624 ,  625  may be applied to the head lap portion of a lower, adjoining first tile  602  and to the roof substrate  23 , and the tile is then positioned so that it contacts the adhesive pads  624 ,  625 . 
     It will be appreciated that the method of applying roof tiles, as described hereinabove, increases the efficiency and reduces the cost for the installation of tile roofs. No complex two-component adhesive foam pressurized supply is needed, and significantly less amounts of foam are used in the application, leading to material cost savings. Additionally, the corner-corner pattern does an unimpeded air channel between the undersurfaces of the tiles and the roof substrate. 
     It will be appreciated that the embodiments of the present invention which have been discussed are merely illustrative of some of the applications of this invention and that numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of this invention. For example, the adhesive deposits may, in some application, take the form of beads applied in alignment with the leading and trailing edges of the tiles provided they do not subdivide the interstitial areas into discrete subareas. The deposits may also resemble mounds or piles.