Pressure-treated wood foundations (also known as permanent wood foundations, or PWFs) have been around at least since the 1940s, and my own experience with them dates back 20 years or so. During my first year on my own as a framing contractor, I was framing homes for a large builder who used wood foundations on many of his projects. Although I was confident of my ability to frame the job from the foundation up, my experience with PWFs was limited. Fortunately, the builder was good enough to assign one of his own experienced carpenters to help me out on my first foundation.
That job went well, and today I still use variations of that same design. I've tweaked some elements, but the overall process has changed very little.
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