This week we filled the walls and remaining ceiling cavity with R-15 Rockwool. If you’ve been following us for a while you might remember that we already have 2 inches of polyiso foam in the ceiling, which combined with the mineral wool gives us a total roof R value of 28. Our walls are standard 3.5” R-15 Rockwool batts, and our floor is insulated with 1 inch of XPS foam for a thermal break, plus 5.5” of mineral wool, giving us R-28 in the floor as well. I’d love to see all those numbers a but higher, but in general I feel like that’s pretty good considering the limitations of tiny house construction.
I’m really enjoying working with the Rockwool. As I write this I’m still itchy and covered with fibers, but far less so than if I’d been working with fiberglass. I find the rockwool easier to cut, it holds its shape and doesn’t slump down in the walls, and the friction fit works amazingly well. I love that I just pop the batts into the stud bays and they STAY where I put them. It’s easy to cut around electrical boxes and I’ve picked up a few tricks for folding it around plumbing and wiring that I’ll share in the insulation video we’ve got in the works.
It feels good to get everything in place in preparation for closing up the walls. Next up, drywall!