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CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of priority from U.S. Provisional Patent Application Ser. No. 60/593,505 filed on Jan. 20, 2005, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention generally relates to construction materials and, more particularly, to specially configured synthetic boards for providing water-tight exterior surfaces such as for decks, roofs, siding, and boat applications.  
       BACKGROUND OF THE INVENTION  
       [0003]     In the construction of outdoor surfaces, such as decks and porches, it is common to use flat materials that are weather-resistant. Typically, these are pressure-treated wood, cedar or teak planks, mahogany planks and, more recently, synthetic boards which are extruded wood/plastic composites.  
         [0004]     In normal construction, boards of the above types are spaced apart to provide gaps, allowing moisture to drain through the crack fromed between the butt joint as from a deck to the area below. Problems arise when it is required that the area below be more or less protected from rain and snow as, e.g., when a patio is placed below an elevated deck.  
         [0005]     Solutions for this problem are available on the market today, but all have certain limitations. Interlocking aluminum planks (e.g., U.S. Pat. No. 5,816,010) are effective in providing leak-resistant lower levels. Various underlayments, covered with rubber or plastic sheet goods, are generally available. These are also effective.  
         [0006]     However, there are two drawbacks with the above. First is appearance; many prefer the look of a traditional wooden floor. A second is related to construction techniques in that the above-cited existing systems require non-standard carpentry, e.g., pre-drilling and sawing of aluminum extrusions and cementing of large areas of sheet goods.  
         [0007]     Consequently, one primary object of the present invention is to provide construction materials in the form of leak-resistant boards which are both attractive, i.e., wood-like in appearance and that are amenable to being worked with ordinary carpentry tools, techniques, and fasteners.  
         [0008]     An additional object of the invention is to provide a low-cost and environmentally friendly means for producing wood-composite materials with the desired leak-resistant properties since the use of various products such as pure wood or plywood is presently expensive and accelerates forest depletion.  
         [0009]     Materials that come in various compositions of wood particles and plastic have been available for many years. Their advantages over natural wood include greater durability and resistance to weathering. They are also often less expensive to manufacture than traditional wood or aluminum products and have the benefit of being producible from recycled plastic and wood products. In addition to these manufacturing benefits, wood-plastic composites have the same workability as wood with respect to the use of traditional carpentry tools and fasteners, and conventional methods for their fabrication have been well established.  
         [0010]     One method of generating wood-plastic materials is by heating mixtures of the composites and applying an extrusion process whereby the melted mixture is forcibly passed through a converging die assembly with the desired cross-sectional shape. For example, U.S. Pat. Nos. 5,746,958 and 5,851,469 describe methods for mixing and stabilizing such material and extruding the heated composite through a die to provide board-shaped products of desired dimensions. Such a process could be adapted for shaping materials with novel dimensions and features (i.e., channels) meant for creating leak-resistant characteristics.  
         [0011]     A further object of the invention is therefore to produce wood-like and leak-resistant material with an inexpensive and environmentally-friendly fabrication process.  
         [0012]     Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter when the detailed description is read with reference to the drawings.  
       SUMMARY OF THE INVENTION  
       [0013]     The invention relates to channeled, interlocking boards with integral elastomeric or supplemental seals that are effective in constructing extensive, leak-resistant lateral surface, as for a deck, roof, wall or boat application.  
         [0014]     In material content, the boards are typical of the composites now used for decking: 50% more or less of wood fibers, the remainder, of thermoplastic binders, typically high and low density polyethylenes. Alternatively, more or less plastic can be used.  
         [0015]     Such boards are wood-like in appearance, extremely rugged and inexpensive. The low cost derives from the fact that the wood content comes from waste sawdust, and the plastic is from recycled goods, such as bags and bottles. Inexpensive processes for producing boards of such material can be adapted for incorporating the desired leak-resistant characteristics. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The structure, operation and methodology of the invention, together with other objects and advantages thereof, may best be understood by reading the detailed description in connection with the drawings in which each part has an assigned label or numeral that identifies it wherever it appears in the various drawings and wherein:  
         [0017]      FIG. 1  is a diagrammatic perspective view of a completed deck structure assembled with boards according to the invention;  
         [0018]      FIG. 2  is a diagrammatic perspective view of a single basic board according to the invention;  
         [0019]      FIG. 2A  is an enlarged cross-sectional view of part of a channel of the board of  FIG. 2 ;  
         [0020]      FIG. 3  is a diagrammatic, partially exploded, view of a pair of basic boards, showing the interlocking features;  
         [0021]      FIG. 4  is a diagrammatic perspective view of a beginning and finishing board according to the invention;  
         [0022]      FIG. 4A  is an elevation of the board of  FIG. 4 ;  
         [0023]      FIG. 5  is an elevational view of an assembly of basic boards, including beginning and finishing boards according to the invention;  
         [0024]      FIG. 5A  shows an alternative means for sealing a beginning board against a vertical wall;  
         [0025]      FIG. 6  is a diagrammatic view of boards with an alternative geometry for outwardly facing channels in accordance with the snap-fit features of the invention;  
         [0026]      FIG. 6A  is an enlarged diagrammatic view of the channels of  FIG. 6 ;  
         [0027]      FIG. 7  is a diagrammatic, partially exploded view of boards with an alternative geometry, along with separate channel sheets in accordance with the invention;  
         [0028]      FIG. 8A  is an elevational view of the boards and channel sheets of  FIG. 7 ;  
         [0029]      FIG. 8B  is a blown-up elevation view of the joint and channel section of the boards of  FIG. 7 ;  
         [0030]      FIG. 9  is a diagrammatic, partially exploded view of the boards of  FIG. 7  with an alternative design for laterally extending channel sheets;  
         [0031]      FIG. 10  is a diagrammatic perspective view of the boards of  FIG. 7  joined lengthwise along the channel sheets of  FIG. 9 ;  
         [0032]      FIG. 11A  is an elevational view, partially exploded, of the boards of  FIG. 9  fastened and sealed to underlying surfaces;  
         [0033]      FIG. 11B  is an enlarged elevation view of joint and channel section of the boards of  FIG. 11A ;  
         [0034]      FIG. 11C  is an elevational view of the boards of  FIG. 9  with alternative means for fastening to an adjoining vertical surface;  
         [0035]      FIG. 12  is a diagrammatic cross-sectional elevation of an alternate embodiment of the invention provided with an enlarged fastening surface; and  
         [0036]      FIG. 13  is a diagrammatic cross-sectional elevation of an alternate embodiment of another embodiment of the invention having yet another enlarged fastening surface. 
     
    
     DETAILED DESCRIPTION  
       [0037]     This invention relates to the production and use of materials suitable to provide extensive generally planar surfaces, such as a deck roof, or wall, which are water-tight to the areas enclosed, thus allowing such areas to be useful as protected areas, e.g., a patio, second deck, porch, storage, or living space. Additionally, the materials appropriately sized may be used in boat applications such as for hulls, decking, interior finishes, and topside structures.  
         [0038]     Referring to  FIG. 1 , a diagrammatic perspective view of a completed deck structure  50  is shown assembled with boards  52  according to the invention. Boards  52  are sealed from moisture and are otherwise configured to channel water out and away from sheltered area  54 .  
         [0039]     Reference is now made to  FIG. 2 , which shows an embodiment of a board  100 . Board  100  is shown with opposite outward facing channels  106 , provided with elastomeric strips  102 , which are applied in channels  106  and which seal against moisture when compressed by opposing tongues  104 . Such strips are preferably co-extruded with the body of boards  100  in a manner to be described, or may be added in a secondary operation. The boards  100  can alternatively be covered entirely with elastomeric material. Note that the durometer of the elastomeric strips  102  is low, typically Shore  40 A, to avoid undue stress in the board structure as the strips are compressed. Note also, that for clarity, the boards are shown dramatically foreshortened; Width “W” is typically several inches, Length “L” is typically several feet or more and can be made in standard lengths as needed. The elastomeric strips may be from the group of materials consisting of silicon, RTV, caulking compound, rubber, latex, and any of these in the form of an O-ring  
         [0040]     Reference is now made to  FIG. 2A , which is a magnified view of the elastomeric strip  102 , shown as a thin meniscus, typically of polyurethane. Circular cross-section seals (O-ring style) laid into extruded channels are more appropriate in secondary fabrication operations.  
         [0041]     Reference is now made to  FIG. 3 , which is a perspective view of two basic boards  100 , slightly separated from their assembled positions. Here, it can be seen that on every joint formed by mating the complimentary shaped channels  106 , there are two side-by-side seals  102 , providing improved water tightness.  
         [0042]     Reference is now made to  FIGS. 4 and 4 A, which are, respectively, perspective and elevational views of a needed additional board configuration  200 , to be used at the beginning and finishing boundaries of the extensive spans of basic boards  100 . One side presents a rounded nose feature, seen at  208 . The other side, to mate with basic boards  100 , features identical channels  206 , upwardly extending tongues  204  and elastomeric strips  202 . The use of beginning and finishing boards  200  is best shown in  FIG. 5 .  
         [0043]     Reference is now made to  FIG. 5 , which is an elevation of a typical construction. (Only two basic boards  100  are shown for clarity. There would typically be many more in the main span.) A beginning board  200 , on the left of the drawing, is shown to be in proximity with a vertical member  310 . Such a member is, for example, siding on a structure or a riser on a stair, on which the subject boards are to form the tread.  
         [0044]     The joint between board  200  and vertical member  310  is sealed with a bead of caulk  302  or alternatively suitable flashing can be used. The finishing board  200 , on the right side of the drawing, finishes the run of boards  100  in a neat and workmanlike manner.  
         [0045]     Still referring to  FIG. 5 , the boards  100  and  200  are fastened to joists  312  with standard decking screws  308  without pre-drilling. However, in certain applications, the use of predrilling may be desired and special screws provided with self-sealants may be used. Screws  308  are typically stainless steel, galvanized or ceramic coated for corrosion resistance. As mentioned, they may also be of the self-sealing variety.  
         [0046]     Reference is now made to  FIG. 5A , which shows, in elevation, the use of a metal flashing strip  306 , lead or aluminum, as an alternative to caulk  302 . This is appropriate to lap siding, such as clapboards or shingles.  
         [0047]     Reference is now made to  FIGS. 6 and 6 A, which are both diagrammatic elevational views showing an alternatitive snap-fit joint configuration for assembling boards  300  in accordance with the invention. Here, tongues  320  of each channel  330  are configured and arranged to provide both camming action and flexibility so that, as the channels  330  are slid toward one another to form a joint, the camming action causes them to flex about their root sections. This bending causes their ends to enter a relief area  350  ( FIG. 6A ) formed in each channel  330 . Upon being pushed together further, the flexed tongues snap back to complete the joint. The snap-fit mechanism together with hidden nails  310  secure the boards to the attachment surface. The base of channels  330  provide sufficient surface area for nails  310  so that the surface areas of the subject boards are flush at interlocked joints. Elastomeric strips  202 , shown as thin menisci, seal against moisture when compressed by opposing tongues  320 .  
         [0048]     Reference is now made to  FIG. 7 , which is a diagrammatic perspective and partially exploded view of an alternative embodiment of the invention, combining boards  402  with channel strips  404 . Tongues  408  of channel strips  404  fit into complimentary configured grooves  406 . Water flows between boards  402  and into channels  404  which are angled to direct water away from a sheltered area such as  102  (shown in  FIG. 1 ).  
         [0049]     Reference is now made to  FIG. 8A , which shows, in elevation, the boards  402  of  FIG. 7  fastened to a joist  504  with standard decking screws  502 , without pre-drilling.  FIG. 8B  shows an enlarged elevational view of boards  402  engaged with channel strip  404 . If desired, the spacing between the upwardly depending tongues may be dimensioned to provide a tight butt joint between adjacent boards to reduce the amount of moisture that can reach the channels  404 .  
         [0050]     Reference is now made to  FIG. 9  which shows a diagrammatic perspective view of an alternative embodiment for a multi-channel sheet  606 . Channel sheet  606  is extruded to include multiple channels  602  and  604 , and the like, which may be repeated to sensible lengths.  FIG. 10  shows a diagrammatic perspective view of the boards of  FIG. 7  joined lengthwise for extensive spans along channel sheets  606  of  FIG. 9 . Water that may flow into a joint  702  is drained outward along channel sheet  606 .  
         [0051]     Reference is now made to  FIG. 11A  where the boards  402  and  802  are fastened to a joist  806  with standard decking screws  502 , with or without pre-drilling. Channel sheet  606  spans across the bottom side of boards  802  and  402 .  
         [0052]     The finishing boards  802 , on the left and right side of the drawing, finish the run of boards  402  in a neat and workmanlike manner. The joint between board  802  and vertical member  808  is sealed with a bead of caulk  810 .  
         [0053]     Screws  502  are typically stainless steel, galvanized or ceramic coated for corrosion resistance and may be self-sealing.  
         [0054]     Reference is now made to  FIG. 11B , which shows an enlarged elevational view of a board  402  with channel sheet  606 . Here, the channel defined between adjacent board edges can be more clearly seen.  
         [0055]     Reference is now made to  FIG. 11C , which shows, in elevation, the use of a metal flashing strip  804 , lead or aluminum, as an alternative to caulk  810 . This is appropriate for lap siding, such as clapboards or shingles.  
         [0056]      FIG. 12  shows in diagrammatic cross section an elevational view of boards  700  having an alternate channel configuration shown generally at  702  that is provided with a flat elongated surface area  704  to promote ease in fastening operations. A screw fastener, or the like, may be inserted to underlying attachment structure along the centerline to form a robust joint.  
         [0057]      FIG. 13  shows a diagrammatic cross section yet another elevatioinal view of boards  800  having an alternate channel configuration shown generally at  802  that is provided with a slightly angled elongated surface area  804  to promote ease in fastening operations. Elastomeric seals may be provided in either of the channels of  FIGS. 12 and 13  as previously described and may if sensible be extended over the overlapping fastening flat areas to provide even more robust sealing joints.  
         [0058]     It is important to note that this construction system is completely compatible with the customary carpentry of balusters, railings, skirts and the like.  
         [0059]     The inventive boards can be produced using wood-composite materials, having the advantage of being inexpensive while retaining wood-like workability and appearance. One embodiment of production includes a means for generating an easily transportable composite mixture of wood particles and thermoplastic materials (i.e., post-consumer recycled plastics), as illustrated in U.S. Pat. No. 5,746,958. Such material is shaped with the desired features (e.g., the channels shown in  206  and rounded edges  208 ) by passing it under pressure, in a partially or fully melted state, through a converging die shaped accordingly. This process is similar to and may be adapted from an embodiment of U.S. Pat. No. 6,527,532. The extrusion process may also incorporate a means for laminating the elastomeric layer  202 , alternatively covering the entire board. The layer  202  can alternatively be applied separately from the extrusion process.  
         [0060]     Such boards may be used to promote water resistant deck surfaces, roofs, siding, boat decking, and boat hulls. The dimensions of the boards can be appropriately sized in thickness, width, and length, according to the particular application.  
         [0061]     Based on the various described embodiments and teachings of the invention, other variants of it will occur to those skilled in the art and it is intended that such variants be within the scope of the invention as claimed.

Summary:
Specially configured synthetic boards are provided for use with conventional carpentry tools and techniques to form flat, water-tight surfaces such as decks, roofs, walls, boat decks, hulls, and the like. The boards are formed to their desired shape and scale by extruding mixtures of wood particles and thermoplastic materials through appropriate converging dies. In one configuration, the edges of the boards have complementary configured outwardly facing recesses that permit them to be joined to form the watertight surfaces, and in another configuration the boards have features that interact with separate plastic structures to provide water tightness.