Patent Publication Number: US-9845603-B2

Title: Prefabricated slate and tile roofing

Description:
BACKGROUND 
     Slate and tile roofs are extremely durable and considered by many as the most desirable roofing available. Unfortunately, with this status comes a premium price. One of the most costly factors in the installation of a slate and tile roof is the cost of labor. 
     That is, skilled installers are required to properly install slate and tile roofs. Applying too much hammer force while nailing a tile to a roof deck can crack or break a tile. Applying too little hammer force can result in an unsightly loose tile or a tile which is subsequently blown away in high winds. Because there is a general shortage of properly skilled slate tile installers, labor costs for these installers are often so high as to be prohibitive. As a result, architects often opt for less costly roofing. 
     SUMMARY 
     As used herein, the term “tile” is intended to include any and all tiles including those formed of natural materials such as slate and rock as well as fabricated tiles such as fired clay, terra cotta, cement and aggregate tiles. The roofing assembly described herein is particularly well adapted for use with slate tiles. 
     In order to simplify the installation of slate and tile roofs and reduce or eliminate the need for highly skilled roofing installers, a prefabricated slate and tile roofing subassembly has been developed to reduce or eliminate the need for nailing tiles to a roof. 
     The tile roofing system described below can be installed by relatively unskilled labor using common low cost installation tools. This expands the available labor pool for tile installation while potentially reducing the cost of installation labor. This system can also reduce the time to install a tile roof as the prefabricated tile subassemblies described below include several tiles properly aligned in a series and ready for installation as a group. These preassembled series of tiles eliminate the need for the installation of individual tiles. 
     To further reduce the labor cost of installation as well as to reduce the material cost of roofing slate and tiles required to cover a roof, the prefabricated slate and tile roofing subassembly disclosed herein can be used with a two layer or single overlap tile installation system. A two layered, single overlap tile roof reduces the number of tiles required to cover a roof deck and thereby reduces the amount of weight bearing down on the roof deck. This allows architects and builders to specify less costly roof support designs than those required for conventional three layer, double overlap tile roof systems. 
     That is, conventional slate and tile roofs have used a three layered system wherein each tile is overlaid by two staggered upper tiles. By replacing the bottom tile with a layer of weatherproofing material, one layer of tile can be eliminated from each row or course of installed tile. In this manner, each tile is overlaid by a single upper tile. As noted above, this reduces the bearing load on the underlying roof structure and can thereby reduce its cost. 
     Because the weatherproofing material covering a roof deck is typically exposed to the environment along the spaces or gaps between adjacent tiles, it is subject to degradation and damage. A robust dual-layered weather barrier guard is provided to protect the underlying weatherproofing material and extend the useful life of the slate roof. 
     In order to greatly simplify the replacement of worn, damaged, broken or missing tiles, instead of nailing tiles to a structure such as a roof deck, tiles are adhesively bonded to a robust dual-layered weather barrier with an adhesive. In one embodiment, the adhesive can have a rubbery consistency which helps to absorb shock forces applied to the tiles. 
     That is, the rubbery adhesive forms a shock absorbing interface between the tiles and the underlying roofing material and roof deck. This reduces the potential for cracked or broken tiles caused by excessive external loading such as commonly produced by workmen stepping on the tiles. It also reduces cuts and punctures in the underlying roofing material caused by cracked and broken tiles. 
     By using a relatively soft rubbery adhesive such as silicone rubber adhesive, the resulting adhesive bond can be easily broken, either with a manual pull or with a simple bladed scraping tool. No nails need to be removed or replaced during tile replacement. This greatly simplifies tile replacement and eliminates the need for a skilled tile installer to properly nail a replacement tile to a roof deck. 
     The adhesive bond can be formed between a tile and a dual-layered weather guard formed of an underlying metal layer and an overlying plastic layer. A relatively narrow upper plastic layer can be centered over a relatively wide metal layer so that the sides of the metal layer extend beyond the sides of the overlying plastic layer. 
     This configuration of weather barrier provides two benefits. First, a stronger bond can be formed between an adhesive, such as a rubbery adhesive, and a tile as compared to an adhesive bond between a tile and a slick plastic material. Second, the prefabrication of a roofing tile subassembly can be facilitated by providing a low friction surface over the underlying metal layer. That is, when installing a tile on the subassembly, a tile can be more easily slid in proper final position over a smooth plastic layer than over a metal layer. The smoother plastic with a lower coefficient of friction reduces snags when sliding a tile in place during fabrication. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the Drawings: 
         FIG. 1  is a perspective view of a representative tile fastener; 
         FIG. 2  is a side elevation view of the tile fastener of  FIG. 1  fastened to a weatherproofing strip of roofing material; 
         FIG. 3  is a top plan view of  FIG. 2  showing a plurality of tile fasteners fastened to a weatherproofing strip; 
         FIG. 4  is a top plan view of a laminated weather barrier; 
         FIG. 5  is a top plan view of a series of the laminated weather barriers of  FIG. 4  mounted to the weatherproofing strip of  FIG. 3 ; 
         FIG. 6  is a top plan view of  FIG. 5  with a series of slate tiles installed forming a prefabricated subassembly; 
         FIG. 7  is a schematic view of two rows or courses of the subassembly of  FIG. 6  installed on a roof with an upper subassembly shown in dashed lines; and 
         FIG. 8  is a top plan partial schematic view of a pair of subassemblies of  FIG. 6  installed in an overlapped side by side configuration. 
     
    
    
     In the drawings, like reference numbers designate like or similar parts. 
     DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS 
     As shown in  FIG. 1 , a representative example of a slate, stone, or tile roofing fastener  10  formed of a strong wire material includes an upper mounting portion  12 , a shank  14 , two lateral wing portions  18 ,  20  and a hook portion  24 . Additional details of a representative fastener are disclosed in U.S. Pat. No. 8,661,760, which is incorporated herein by reference in its entirety. As used herein, the terms slate and slate tile are used generically to include slate, ceramic and other generally flat roofing tiles. 
     The fastener  10  of  FIG. 1  is shown in  FIG. 2  mounted to a strip or base layer of roofing material  30 . Roofing material  30  can take the form of a water resistant or waterproof sheet of plastic material such as high density polyethylene (HDPE) or a composite material such as commonly referred to as “tar paper”. In the embodiment of  FIGS. 2 and 3  the sheet of roofing material  30  is constructed from a sheet of HDPE 0.025 inch thick, eleven inches high and several feet long or wide. The HDPE can be effectively used as a carrier or base for carrying a prefabricated row of slate tiles, as described more fully below. 
     As further seen in  FIGS. 2 and 3 , a series of spaced apart fasteners  10  is initially mounted on the base layer of roofing material  30  with, for example, staples  34 . Any other fasteners such as rivets or clips may be used. The fasteners  10  can be spaced at regular predetermined intervals. In this example, the fasteners  10  are evenly spaced apart by about 10.25 inches along the top portion  32  of the roofing material  30 , with the bottom  36  ( FIG. 1 ) of the hook portion  24  of the fastener  10  extending downwardly about three inches from the top edge  40  of the roofing material  30 . 
     As seen in  FIG. 4 , at least one laminated dual layer weather barrier  44  is constructed with a top strip  48  of weather resistant or waterproof roofing material such as used for the roofing material  30 . In this example, the top strip  48  can be a one and one half (1½) inch wide strip of 0.025 inch thick HDPE, about nine inches high. As further seen in  FIG. 4 , the top strip  48  is positioned centrally over a thin lower strip  50  of weather resistant or waterproof material. 
     In this example, the lower strip  50  is constructed from a thin sheet of metal, such as a 0.025 inch thick strip of aluminum, about two and one half inches wide and about nine inches high. A thin sheet of metal material, such as aluminum, better withstands degradation from wear due to exposure to ambient weather than does a thin sheet of plastic material such as high density polyethylene (“HDPE”). 
     By dimensioning the lower strip  50  wider than the upper or top strip  48 , side portions  56  of the lower strip  50  extend laterally beyond opposite sides of the top strip  48 . The side portions  56  provide exposed portions of the lower strip to which strong adhesive bonds are formed when bonding a tile to the side portions  56 . 
     A better, more secure and longer lasting bond can be formed between an adhesive and a thin sheet of metal material, such as the lower metal strip  50 , than between an adhesive and a thin sheet of smooth plastic material, such as the plastic top strip  48 . This is because a metal material generally has greater resistance to deformation such as caused by flexing, bending and curling than does a plastic material of the same dimensions. 
     This deformation can degrade or break an adhesive bond. Moreover, because plastic roofing material such as HDPE typically has a glossy low friction surface that does not typically bond well with rubbery adhesives, a stronger bond can be formed on a less glossy or less slippery metal material having a higher coefficient of friction. This can provide a more secure bond for holding a tile on the weather barrier  44 . 
     A hole  52  is punched through a central upper portion of both the top and bottom strips  48 ,  50  for receiving the hooks  24  of a fastener  10 . The top and bottom strips can be fastened together prior to or after punching hole  52 . The weather barrier  44  is mounted on a hook  10  by inserting the hook portion  24  and the bottom  36  of the hook  10  through the punched hole  52 , as shown in  FIG. 5 . 
     As further seen in  FIG. 5 , once the dual layer weather barrier  44  is loosely mounted over the roofing material  30  via fastener  10 , the dual layer weather barrier  44  is permanently fixed to the roofing material  30  such as with the use of adhesives or fasteners such as staples. The spacing of the weather barriers is fixed and determined by the spacing of the fasteners  10 . In the example of  FIG. 5 , one or more rivets  54  clamp each weather barrier  44  to the roofing material  30  at evenly spaced-apart intervals. This results in a first series of spaced-apart weather barriers. 
     Once the weather barriers  44  are mounted and spaced apart at predetermined equal spacings along the roofing material  30  in a generally mutually parallel configuration, a semi-permanent mounting is provided on at least one or more of the weather barriers  44  for receiving and holding a series of slate tiles  66  ( FIG. 6 ) in predetermined positions along the roofing material  30 . By semi-permanent it is meant that during manufacture, shipping, handling and final installation on a roof, the slate tiles  66  will be held securely in place over the weather barriers  44  and the underlying roofing material  30 . However, if a slate tile  66  is damaged at any time either before or after installation on a roof, it can be removed manually without excessive force and without removing any nails. 
     In the example of  FIG. 5 , a rubbery adhesive, such as silicone glue, can be applied on the exposed sides  56  ( FIG. 4 ) of each lower metal strip  50 . Any suitable pattern of adhesive can be applied, such as spaced apart adhesive drops  64 . A superior adhesive bond can be formed between the lower metal strip  50  and the slate tiles  66  compared to a similar adhesive bond formed between a top HDPE plastic strip  48  and the slate tiles  66 . 
     As further seen in  FIG. 6 , a series of slate tiles  66  is pressed over and onto each adhesive drop  64  to form a secure but removable or breakable bond with the weather barriers  44 . Since the weather barriers  44  are fixed to the underlying roofing material  30 , the slate tiles  66 , which are fixed to the weather barriers, are thereby fixed in position over the roofing material as well. Each pair of adjacent tiles  66  overlies the wing portions  18 ,  20  of the underlying portion of a fastener  10 . 
     While all the tiles  66  in this example are adhesively attached to their respective underlying weather barriers  44 , in other examples, at least one or more tiles  66  can be adhesively attached to an underlying weather barrier  44 . The weather barriers  44  protect the underlying roofing material  30  from exposure to the environment through the spaces  62  formed between the side edges  72  of adjacent slate tiles  66 . This in turn protects the underlying roof deck from environmental damage and costly repairs. 
     Moreover, the weather barriers  44  distribute the weight of a workman over a greater area than the potentially sharp edges of the tiles  66  so as to reduce the stress applied to the underlying roofing material  30 . This helps to prolong the useful life of the roofing material by preventing or reducing punctures through the roofing material. 
     In the example of  FIG. 6 , the slate tiles  66  are dimensioned about ten inches wide (side to side) and about nine inches high (bottom to top). The bottom edges  70  of the slate tiles  66  are aligned over or adjacent to the bottom edge  68  of the roofing material  30 . The opposite side edges  72  of the slate tiles  66  are fitted closely between each adjacent pair of roofing fasteners  10 . In this example, the top edges  78  of the slate tiles  66  extend about one inch above the bottom  36  of each hook  10  and about two inches below the top edge  40  of the roofing material  30 . While the drawings are approximately drawn to scale, any other suitable dimensioning of components can be used in accordance with the general teachings set forth herein. 
     Once the adhesive drops  64  dry or cure, the resulting prefabricated roofing subassembly  90  as shown in  FIG. 6  can be shipped to a construction site for installation.  FIG. 7  shows a lower subassembly  90  installed on a roof deck  92  and an upper subassembly  90  in phantom installed on the roof deck  92  over the upper portions  96  of the slate tiles  66  in the lower subassembly. The slate tiles  66  on the upper subassembly  90  are laterally staggered over the slate tiles  66  on the lower subassembly  90  such that the midpoint or center of each tile  66  in the upper subassembly  90  is vertically centered or vertically aligned over a fastener  10  in the lower subassembly. 
     The lower edges  100  of the slate tiles  66  in the upper subassembly  90  are firmly seated in the mouths of the hooks  24  on the lower subassembly  90 . The hooks  24  are dimensioned to project upwardly from the base layer  30  and between and above each adjacent tile  66  so as to receive the lower edges  100  of the tiles  66  on an upper subassembly  90 . Each subassembly  90  can be permanently fixed to the roof  92  with roofing nails  102 , staples  104  or any other type of fastener or adhesive. Each subassembly  90  can be cut to length as needed or extended by overlap with another subassembly as shown in  FIG. 8 . 
     For example, as seen in  FIG. 8 , the free lateral end portion  108  of the roofing material  30  on one subassembly  90  can be slid in the direction of arrow  110  under the free end portion  112  of the roofing material  30  on an adjoining subassembly  90 , until the side edge  72  of the moving slate tile  66  abuts the fastener  10  on the adjoining subassembly  90 . In this example, the two subassemblies  90  are shown slightly vertically offset from each other for purposes of clarity and detail. However, in practice, the two subassemblies  90  are more closely aligned in a straight row with the top edges  40  and bottom edges  68  of the roofing material  30  aligned in straight lines. 
     Because this method of installation is similar to that used to install common asphalt shingles, those roofing installers familiar with the installation of asphalt shingles can quickly adapt to the installation of the tile roofing system using subassemblies  90 . This increases the number of roofing installers potentially available for installing the tile roofing system disclosed above and can potentially reduce labor installation costs. 
     There has been disclosed the best embodiment of the prefabricated slate and tile roofing assembly as presently contemplated. Numerous modifications and variations of the roofing assembly are possible in light of the above teachings. It is therefore understood that within the scope of the appended claims, the slate tile roofing concepts may be practiced otherwise than as specifically described herein.