We have been working at getting the foundation installed for our Passive house project. It has taken quite a bit of time to get things squared away. We first laid down a layer of rock to allow water and radon to migrate properly. However, once that was in place the structural engineer was concerned about the extruded foam insulation under the footings settling into the rock. So we first laid a 2″ thick layer of concrete on top of the clean rock. On top of that we put 6″ of foam insulation….and put 8″ of foam at the basement floor. On top of the foam we put 8″ of clean sand. The conduits and plumbing pipes go in the sand area….being installed in this photo. Once the piping work is done we will install reinforcing steel, in-floor heating tubing, and then pour the basement floor and integral perimeter footing.