Neal and I took the insulation from the temporary wall and started filling the 2X6 walls with Roxul bat insulation. I'm happy I went with Roxul stone wool insulation. Not only is it fireproof, it doesn't itch when you touch it. It literal took a mountain of insulation to fill all the walls.To insulate the flat ceiling of the office/retail space, I went with spray foam insulation. I decided to go with 6 inces of insulation to match the R36 insulation value of the SIPs in the distillery space. The spray foam team arrived in a truck filled with vats of insulation that looked like something from Breaking Bad.
One hotly debated issue was how to vapor barrier the SIPs. Normally, a sheet of plastic is put on the warm side of the roof to prevent moisture from getting into the insulation cavity. But SIPs are made up of a sandwich of OSB (oriented strand board) and rigid insulation. Since OSB is a vapor barrier, Paul worried that putting plastic over it could trap moisture between the two vapor barriers. I asked my building inspector, Michael, for his opinion. He agreed that OSB can be a vapor barrier provided that the joints are properly sealed. He suggested I use a high performance European tape to seal the joints and gave me the name of a supplier who might have some. Paul agreed with Michael's suggestion, so I sent Neal to Herrmann Timberframe to get some. I wish I got to make the trip because Neal said that it was quite the place. Andreas, the owner, immigrated from Switzerland in the 1990s and started building timber frame homes in Ontario. He saw an opportunity to bring Swiss and German construction products to Canada. Neal purchased his SIGA tape to seal the SIP joints of the distillery roof.
It took Neal and I a whole weekend to tape all the joints but I feel the effort is worth it. The only time SIP panels have failed is when vapor entered the joints and condensed causing the OSB to rot. By sealing all the joints, I won't have this problem.