The mud sills provide a bearing and attachment surface for the ends of the i-joists. First we needed to install a floor beam in the crawlspace, running almost the full length of the house.
The floor beam is made of the same 8 x 8 timbers we are building with. That meant tearing the tarps off the lumber stack and selecting the first pieces. They had to be straight and true, and the right length so we would minimize waste. We found three nice timbers to use for the floor beam and the posts that hold it up.
This was the first use of a cheap little jig I bought several years ago called the Beam Machine. It’s intended to cut boards from logs, but we turned it 90° and used it as a cutoff saw attachment for a small chainsaw. Even though this is chainsaw carpentry and we are working with big timbers, the floor beam called for accuracy and even cuts. Otherwise we might end up with a squeaky floor.