The insulation went in yesterday. Easy-peasy! They just spray it (icynene) into the walls in a very thin layer and it puffs up to fill the wall space. We would have loved to use something totally sustainable, but this was the closest we could get for what we needed. Icynene is a petroleum product, but it is supposed to be more air quality friendly and non toxic. It’s also more energy efficient.See the thin, white spray on the upper left wall…

Here’s what it puffs into:

Cool, eh?