US Patent 7189045 Deck screws suitable for use with composite lumber

A deck screw is intended for use with composite lumber, although it can be used with other wood products, such as pressure treated lumber. The deck screw has a head and a shaft that has two regions of different diameter. The upper region has threads that exceed the number of threads of the lower shaft, on a unit length basis. The threads of the upper shaft may be configured in an inverted buttress design. The lower region of the shaft terminates at a tapered distal end having a pointed tip that leads the screw through the wood material. Threads are provided on the lower region of the shaft. A crown extends around the perimeter of the head.