Treated wood foundations are load-bearing, pressure-treated wood framed walls, used below grade to support light frame construction. Treated wood foundations are commonly called Permanent Wood Foundations or All-Weather Wood Foundations. Since being developed in the 1960s, this unique building system has had its skeptics; however, it has proven to be a durable building system in thousands of physical applications. Treated wood foundations have undergone extensive research, analysis, and testing by several highly respected organizations within the building construction industry. They have been approved for use by model building codes, many state and local building codes, federal agencies, and by lending, warranty and insurance institutions. A treated wood foundation, when installed, waterproofed, and drained properly, and used in conjunction with other waterproof materials, is a viable alternative to poured concrete or concrete block foundations.