Abstract: A novel planking system utilizing an inventive groove design is provided. The novel groove is defined by two opposing side walls and a groove end wall. The groove side walls present two generally opposed tongue-engaging projections that automatically provide a uniform space between planks during installation, and accommodate expansion of the planks after installation by breaking away when force is exerted on the projections by an adjacent plank. The present invention is also concerned with a combination of planks having an inventive tongue-and-groove configuration, as well as inventive methods of assembling planks to accommodate the expansion and contraction of the assembled planks after installation.

Abstract: A novel planking system utilizing an inventive groove design is provided. The novel groove is defined by two opposing side walls and a groove end wall. The groove side walls present two generally opposed tongue-engaging projections that automatically provide a uniform space between planks during installation, and accommodate expansion of the planks after installation by breaking away when force is exerted on the projections by an adjacent plank. The present invention is also concerned with a combination of planks having an inventive tongue-and-groove configuration, as well as inventive methods of assembling planks to accommodate the expansion and contraction of the assembled planks after installation.

Abstract: An extruded composite structural artificial lumber product is manufactured from wood fiber and polyethylene, including recycled polyethylene, by reducing the wood fiber and polyethylene each to a finely divided particles, mechanically mixing the wood fiber and polyethylene particles together with a measured amount of a powdered endothermic foaming agent, mechanically mixing the mixture, without pre-pelletization, in a twin-screw extruder where it is compressed and heated until it becomes plastic and homogenous, and then extruding the plastic mixture, using vacuum to remove vaporized moisture and other excess volatiles, through a molding die which forms structural profile of the desired product.