ROOFING PANEL SYSTEM
Field of the Invention This invention relates to roofing panels which can be used to construct a weather-resistant roof without the use of shingles or similar coverings. The weather- resistant roof may be an original roof or a replace¬ ment/repair of an original roof. The roofing panels comprise a wood product sheathing panel which .has been coated on one side with roofing granules which are bonded to the sheathing panel with a weather-resistant adhesive.
Background of the Invention Various products and methods are known for roofing houses and other buildings. Although the known systems differ in their details, they typically involve cover¬ ing the roof supports with boards or sheathing panels (e.g. plywood or waferboard). The method of attachment is usually with fasteners such as nails or staples or a suitable construction grade adhesive or a combination of such techniques. After the roof supports are covered, the boards or sheathing panels are then covered with a moisture barrier such as a treated felt paper and the resulting surface is then covered with shingles, roll- roofing, tar or the like to thereby achieve a weather- resistant roof.
Such techniques involve a significant amount of on-site labor and may involve different skilled trades.
Consequently, there is an incentive to develop roofing systems that can be more economically installed for an original roof and for roof replacement and repair.
Summary of the Invention
The present invention is based upon the discovery of an alternative roofing system in which a sheathing panel made of wood (e.g. plywood or waferboard) is precoated with roofing granules that have been adhesive-
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ly bonded to substantially one entire side of the sheathing panel. A typical sheathing panel of this type will have nominal dimensions of from 4 feet by 8 feet up to as much as 8 feet by 28 feet, or even larger. By using pre-coated sheathing panels of this type, a finished roof can be obtained in essentially one step by merely fastening these roofing panels to the roof supports and then sealing the joints between adjacent roofing panels. If desired, the seams between adjacent panels can simply be coated with a suitable adhesive or caulk, with or without additional roofing granules being sprinkled over or mixed with the caulking or sealing material, or the seam may be covered with a suitable tape which may optionally and preferably be covered with matching roofing granules.
Although the roofing panels of the present inven¬ tion may be fabricated at any site away from the con¬ struction site, it is convenient for the roofing panels to be fabricated at the place where sheathing panels are manufactured.
The roofing panels of the present invention may also be used to re-roof an existing roof that needs to be replaced by either placing the roofing panels over the existing shingles or tearing down the original roof to the sheathing and then using the roofing panels. Description of the Drawings The present invention will be further understood by reference to the following drawings. Figure 1 illustrates a roofing panel made accord¬ ing to the present invention.
Figure 2 illustrates one method of constructing a roof using roofing panels of the present invention.
Figure 3 illustrates one method of positioning and sealing two roofing panels made according to the present invention.
Figure 4 illustrates one method of finishing the
edge by the eaves of a roofing panel made according to the present invention used in constructing a roof.
Figure 5 illustrates one method of constructing the peak of a roof using roofing panels of the present invention.
Figure 6 illustrates another method of construct¬ ing the peak of a roof using roofing panels of the present invention.
Figure 7 is a side view taken generally along the line 7-7 of the illustration of another method of constructing the peak of a roof as shown in Figure 6.
MATERIALS USED IN MAKING THE ROOFING PANELS The Sheathing Panels
Although the present invention is broadly appli¬ cable to roofing panels which are made from any sheath¬ ing panel made of wood (e.g. plywood, waferboard, etc.) it will be described with particular reference to waferboard because waferboard is particularly well- suited for use in the present invention.
Although the basic manufacture of sheathing panels made of wood does not form an inventive part of the present invention, some description of the manufacture of wood panels other than plywood may be helpful to a full understanding of the present invention.
The manufacture of wood panels from small wood fragments such as chips, fibers and wafers is known and is different from the manufacture of multiple ply products such as ordinary plywood. Typically, the manufacture of panels from small wood fragments involves converting the wood into fragments suitable for the particular process being employed, mixing the wood fragments with a suitable adhesive, and then molding the resulting mixture into the desired shape. Often the desired shape is in the form of large panels which are known to the trade by such diverse names as particle
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board, chip board, and waferboard depending upon the particular method and products from which the particular boards are made. Numerous variations of board-making processes exist and each type of wood fragment and each type of adhesive poses its own special processing needs and offers its own advantages and disadvantages.
The resulting wood panels have numerous applica¬ tions depending upon their own characteristics such as their density, strength, water-resistance, and cost. However, wood panels made from wood fragments have their own characteristic appearance which is different from that of solid wood boards and paneling.
In a classic method of manufacturing sheathing panels from wood wafers, de-barked logs are cut into standard lengths and then fed to a waferizer which typically contains a series of revolving knives which serve to cut thin ribbons of wood from the short logs. These ribbons of wood break into short lengths called "wafers". The resulting wafers are dried and then mixed with a suitable exterior adhesive (e.g. less than 10 percent, usually less than 3 percent of adhesive based upon the weight of the finished panel) and a wax (e.g. less than 3 percent, usually less than one percent of the wax solid based on the weight of the finished product). The wax is often used as an aqueous emulsion, typically 50 percent wax and 50 percent liquid. This wafer/adhesive mixture is then used to form a mat by depositing the mixture over the surface of a caul until a preselected depth of the mixture is reached. Next, the resulting mat is pressed at an elevated temperature in a large heated hydraulic press until the mat has been compressed to the desired thickness and the adhesive has been set. The presses, which frequently have multiple press openings, are then opened and the large waferboard panels are removed. The panels are then allowed to cool and may be cut into smaller sizes
or trimmed before or after cooling.
These waferboard panels, as well as other sheathing panels, have nominal thicknesses of 1/8 inch up to 1 inch or more, usually 1/4 inch to 3/4 inch. Panel sizes are usually 4 feet by eight feet or larger {e.g. 4 feet by 12 feet or 8 feet by 28 feet). The Adhesives
Any suitable adhesive can be used for the purposes of the present invention so long as it has the desired characteristic of weather-resistance. Suitable adhesives include one and two component polyurethane systems, epoxy resins of various types including the bisphenol epichlorhydrin resins, asphaltic materials, and the like. If desired, the adhesives will optionally include various additives to improve their weather-resistance or other properties such as conventional UV absorbers, fire retardants, colorants, fillers, and the like. Roofing Granules
Any roofing granule may be used, although all do not serve with equal effectiveness. The granules may be smoothe or irregular in shape and may be made of organic or inorganic materials such as silicates (e.g. sand), pulverized rock, glass beads or crushed glass beads, plastic or metal chips, etc. The size of the roofing granules may vary widely, but for most applications granules having a maximum dimension of less than 10 millimeters, usually less than 5 millimeters, e.g. about 1-3 millimeters, will be acceptable. Method of Making the Roofing Panels
The method of making the roofing panels of the present invention can be understood by reference to the drawings.
As shown in Figure 1, a roofing panel generally designated by the numeral 1, comprises a sheathing panel
2 (e.g. waferboard). Typically the panel 2 is polygonal shaped for use on structures such as a geodesic dome and
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is rectangular shaped for structures as shown in Figure 2. One side of the sheathing panel 2 is coated with roofing granules generally designated by the numeral 3 which have been adhesively bonded to the sheathing panel 2 with adhesive 4.
If desired, the sheathing panels can be precoated or pre-treated with preservatives, weather-resistant coatings, and active or latent adhesives (e.g. a solvent activated adhesive) before applying the roofing gran- ules. Although the roofing granules 3 and the adhesive 4 can be premixed before coating sheathing panel 2, it is generally convenient to first coat the sheathing panel 2 with adhesive 4 (e.g. coated to a depth of 5 to 100 mils, usually 10 to 40 mils) and then substantially completely cover the wet adhesive with roofing granules
3 which become firmly bonded to the sheathing panel 2 when the adhesive 4 has cured or hardened.
Although an entire side of sheathing panel 2 can be coated with adhesive 4 and roofing granules 3, it is preferred to fabricate the roofing panels 1 by a process in which roofing granules are substantially excluded within a narrow border 5 along at least one edge of the granule/adhesive coated sheathing panel 2. However, this border can be, and preferrably will be, coated with the adhesive 4. By substantially eliminating the roofing granules in this narrow border, the narrow, granule-free border permits an effective sealing tech¬ nique to be used for sealing the seams between two adjacent roofing panels. The details of this sealing procedure are described under the heading "Methods of Constructing a Weather-Resistant Roof". Typically the width of this border will be on the order of 2-10 centimeters wide on roofing panels of a size of at least
4 feet by 8 feet. Optionally and preferably, each roofing panel will be provided with at least two borders which are substan¬ tially free of roofing granules. Although granule-free
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borders can be provided along all four edges of a rectangular roofing panel, it is preferred to have such borders along three edges, only, for reasons which are hereinafter explained. For other polygonal shaped roofing panels, such as those used for geodesic domes, it may be preferable to have some roofing panels with such a border along all of the edges. It is understood that the shape of each roofing panel is not limited to a rectangle or polygon, but may be any closed surface shape.
The cure time of the adhesives can be shortened by the use of heat or catalysts or both. Consequently, a convenient time to apply the adhesive and roofing granules to a sheathing panel is at the conclusion of the manufacturing process of the sheathing panel when the panel typically has some retained heat as a result of its own manufacturing process. For example, when waferboard is manufactured it is hot pressed as part of the manufacturing process. When the large sheets of waferboard (e.g. slightly larger than 8 feet by 28 feet) are removed from the heated press, they are trimmed and allowed to cool to room or warehouse temperature. Consequently, it is useful if the adhesive and roofing granules are applied to the waferboard panels while the panels still have some retained heat, thereby taking full advantage of the available energy. In manufac¬ turing process where the waferboard panels are allowed to cool, it is useful to preheat the panel before applying the adhesive and roofing granules. One method of heating is to use an infra-red radiation source. Methods of Constructing a Weather-Resistant Roof In constructing weather-resistant roofs by use of the present roofing panels, it is convenient and prefer¬ red (but not necessary) to do one or all of the follow- ing:
(1) Fabricate the roofing panels in standard sizes so that their longest dimension is substantially
equal to a number of different but commonly en¬ countered roof peak-to-eave distances (16 feet, 18 feet and 20 feet) of a standard 4-12 pitch roof.
(2) Manufacture the roofing panels in standard widths such as 4 feet or 8 feet wide so as to match the normal spacing of roof supports (e.g., 16 inches or 2 feet on centers).
(3) Fabricate each standard size of roofing panel into two types, one type being provided with a granule-free border along two adjacent margins of the panel and the other type being provided with three granule-free borders.
The method of constructing a weather-resistant roof according to the present invention can be understood by reference to Figure 2. While the method shown and hereinafter described is for constructing an original roof, it is understood that the roofing panels may also be used to replace an existing roof.
As shown in Figure 2, a building generally design- ated by the numeral 20 has a series of roof supports 21. A series of roofing panels are selected which have their longest dimension equal to the peak-to-eave distance of the building 20 and the panels are applied to the roof supports 21 with the end panel 22 having only two granule-free borders with the intermediate panels 23 being provided with three granule free borders. The panels 22 and 23 are suitably attached to the roof supports with fasteners such as nails or staples or adhesive or a combination of fasteners. After the roofing panels 22 and 23 are in place, the seams are sealed. The seams may be sealed by merely caulking the seams with any suitable caulking material (e.g. butyl rubber caulk). Cosmetically, it is desirable if the seams are covered with additional adhesive to at least the full width of the granule free borders and then additional roofing granules of a matching color are sprinkled over the wet adhesive to thereby form a
weather proof seal and cos etically match the sealed seam with the remainder of the roofing panels 22 and 23. It is understood that in some cases the roofing panel may not fully extend from the peak to the eaves and it may be necessary to have more than one panel to cover such a distance. This would therefore require a hori¬ zontal seam between two panels.
As shown in Figure 3, the roofing panel 30 com¬ prises a sheathing panel 33 coated with roofing granules 35 which have been adhesively bonded to the sheathing panel 33 with adhesive 34. The roofing panel 30 has a granular free border 39. Two roofing panels 30 are applied to a roof support 31 and are suitably attached to the roof support 31 with fasteners such as nails or staples or adhesives or a combination of fastners. The seam between the roofing panels 30 is then sealed. For convenience and weatherability, it is preferred to seal this seam with an adhesive coated tape 37 which is placed over the seam and bonded to the roofing panel 30 within the granular free borders 39. Desirably, the tape 37 will be precoated on one side with matching roof granules 38 and on the other side with a contact adhe¬ sive 32 covered with a suitable release film. If the tape has not been precoated with roofing granules 38, it may be covered with additional adhesive and sprinkled with additional granules to improve both its appearance and weatherability. The same technique can be used at the roof peak, in valleys and at vents or chimneys. By not having a granule free border on the panels along the eaves, no special treatment of the panels 22 and 23 is required along the eaves. However, Figure 4 shows a preferred method of construction along the eaves. A roofing panel designated by the numeral 43 comprises a sheathing panel 42. The sheathing panel 42 has a top side 44, an end 45 and a bottom side 46. The top side 44, end 45 and a portion of the bottom side 46
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proximate to the end 45 are coated with an adhesive coating 47 (e.g. polyurethane) . Roofing granules 48 are coated on the adhesive 47 on the top side 44. Roofing granules 48 may also be coated on the end 45 and a portion of the bottom side 46 proximate to the end 45. The roofing panel 43 is suitably attached to the roof support 41 and facia board 49 with fasteners. The bottom side 46 is sealed to the facia board 49 by merely caulking the seam"with any suitable caulking material (e.g. butyl rubber caulk).
It is understood that there are numerous suitable methods of sealing the seams. For example, metal strips may be fastened over the seams to seal the seams.
One method of finishing the peak of a building is shown in Figure 5. Roofing panel 53 comprises a sheath¬ ing panel 52. The roofing panels 53 are suitably attached to the roof supports 51. One side of the sheathing panel 52 is coated with roofing granules 58 which have been adhesively bonded to the sheathing panel 52 with adhesive 55. The roofing panel 53 has a gran¬ ular free border 59. The bottom edge of the roofing panels 53 meet at the peak of the roof and form a dead space 50. The dead space 50 between the two roofing panels 53 is preferably filled with a suitable caulk 56, although this is not required. An adhesive coated tape 54 having a roofing granular backing 58 is placed over the dead space 50 and bonded to the roofing panels 53 within the granular free borders 59. Desirably, the tape will be precoated on one side with matching roofing granules and on the other side with a contact adhesive covered with a suitable release film. If the tape has not been precoated with roofing granules, it may be covered with additional adhesive and sprinkled with additional granules to improve both its appearance and weatherability. Alternately, the tape may be constructed such that the additional granules may be simply pressed into the tape itself and thereby held in place.
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A preferred method of finishing the peak of a building is illustrated in Figure 6. The roofing panel 63 comprising roofing granules 68 adhesively coated to the sheathing panel 62 by adhesive 65 are fastened to the roof support 61. Unlike the method as illustrated in Figure 5, wherein the two roofing panels 53 contact one another, the roofing panels 63 are disposed by approximately the width of the base 70 of a ridge vent 60. The ridge vent 60 is preferably metal or plastic and is lightweight. Upper portion 71 of the ridge net 60 has a screen 74, as shown in Figure 7, to allow air to flow in and out of the top of a building. Flange 72 of the ridge vent 60, the roofing panel 63, and a perforated plastic lip 69 are fastened to the roof support 61 by a fastener 64. During a rain, the perfo¬ rated plastic lip 69 deflects the wind and reduces the amount of rain blown into the building via the screen 74. The ridge vent 60 may be further sealed to the roofing panel 63 by a suitable caulking material 66. Other modifications of the invention will be apparent to those skilled in the art in light of the foregoing description. This description is intended to provide specific examples of individual embodiments which clearly disclose the present invention. Accord- ingly, the invention is not limited to these embodiments or to the use of elements having specific configurations and shapes as presented herein. All alternative modifi¬ cations and variations of the present invention which follows in the spirit and broad scope of the appended claims are included.