Synthetic boards for exterior water-resistant applications

Abstract

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.

1 . A substantially planar surface comprising corresponding and interconnected water proof pieces that form water resistant channels between them for directing liquid away from the surface, said water proof pieces having opposed surfaces and edges with at least one lengthwise recess formed in a surface thereof adjacent one edge, said recess facing outwardly from said surface and configured and arranged to engage corresponding complementary shaped recesses in other like water proof pieces to provide surfaces with liquid channeling, leak resistant joints formed between adjoining water proof pieces.  
   
   
       2 . A board for use with other like boards to construct surfaces, said board having opposed surfaces and edges with at least one lengthwise recess formed in a surface thereof adjacent one edge, said recess facing outwardly from said surface and configured and arranged to engage corresponding complementary shaped recesses in other like boards to provide surfaces with liquid channeling, leak resistant joints formed between adjoining boards.  
   
   
       3 . The board of  claim 2  wherein the cross-sectional shape of said recess comprises one concave section and one convex section arranged aside of one another.  
   
   
       4 . The board of  claim 3  wherein said concave section resides further inboard of said edge than does said convex section and is larger than said convex section.  
   
   
       5 . The board of  claim 4  wherein at least a portion of said concave section includes lengthwise sealing means to further assure that a leak resistant joint is formed between adjoining boards.  
   
   
       6 . The board of  claim 5  wherein said sealing means comprises a lengthwise meniscus of flexible sealing material.  
   
   
       7 . The board of  claim 6  wherein said flexible sealing material is selected from the group of materials consisting of elastomers, silicon, RTV, caulking compound, rubber, latex, and O-ring.  
   
   
       8 . The board of  claim 5  wherein said sealing means comprises a lengthwise groove formed in the bottom of said concave section and filled with a sealing material that sits proud of said surface of said concave section.  
   
   
       9 . The board of  claim 2  wherein said recess further includes a section for engaging adjoining boards along at least one common edge.  
   
   
       10 . The board of  claim 5  wherein said recess is configured and arranged as a snap fit joint, said joint having a widened and substantially planar surface at the base of said recess so that fasteners may attach said board to a surface beneath said board through said widened and substantially planar surface.  
   
   
       11 . The board of  claim 10  wherein said recess further comprises: 
 a fastener at the base of said recess sufficiently small so that said board and said complimentary board are flush and so that said fastener is hidden from the top surface of said board; and    a lengthwise seal adjacent said hidden fastener to further assure that a leak resistant joint is formed between adjoining boards.    
   
   
       12 . The board of  claim 2 , wherein said board is comprised of composite materials selected from the group consisting of wood particles and plastic so that the appearance of said board is wood-like, said board being pliabile for use with common carpentry tools and fasteners and strengthened strength for common construction purposes selected from the group comprising decks, roofing, siding, boat decks, and boat hulls.  
   
   
       13 . The board of  claim 12  wherein said plastic is comprised of polyethylene.  
   
   
       14 . The board of  claim 13  wherein said board is formed by extrusion.  
   
   
       15 . The board of  claim 14  having additional structural features formed during extrusion including wire and rod stiffeners.  
   
   
       16 . The board of  claim 5  wherein said sealing means is co-extruded or contemporaneously applied.  
   
   
       17 . A method for producing a wood-plastic composite for a board having opposed surfaces and edges with at least one lengthwise recess formed in a surface thereof adjacent one edge with the recess facing outwardly from the surface and configured and arranged to engage corresponding complementary shaped recesses in other like boards to provide surfaces with leak resistant joints formed between adjoining boards, said method comprising the steps of: 
 a) providing particles of wood component;    b) providing a thermoplastic component;    c) proportioning the wood component and thermoplastic components in a mixing ratio from about 65/35 to about 40/60;    d) heating the mixture; and,    e) extruding the mixture through a die shaped according to the board's desired dimensions and profile.    
   
   
       18 . The method of  claim 17 , further including the step of co-extruding an elastomeric strip along said grooves.  
   
   
       19 . The method of  claim 17 , further including the step of laminating said board with a PVC layer.  
   
   
       20 . A leak-resistant planar surface which channels water away from an underlying area comprising: 
 a plurality of boards aligned adjacent to one another with two lengthwise grooves along the downward face of each board;    channel strips placed underneath the lengthwise boundaries between said boards wherein said strips comprise protruding tongues that insert in a complimentary manner into said grooves of said boards so that said channel strips form channels for directing liquid away from said surface.    
   
   
       21 . The leak-resistant planar surface of  claim 20  wherein said channel strips are formed as an integrated sheet of periodically repeating such channel strips with flat areas spanning and underneath them.