Kooyman Lumber is the area’s premier supplier of GP Floor systems.   GP I-joists are the strongest in the industry. We can custom design a truss system for any house. Kooyman Lumber sells only top grade ACQ treated lumber which meets all industry standards for treated lumber but is friendly to the environment. Our Cedar is top quality and can add beauty to any deck or other outside project. Timbertech and Boardwalk materials are also available as decking materials for those who are looking for an option to traditional wood decks.