galdreth
2021-05-27 10:36:56
- #1
If these are concrete beams with embedded stones, then it’s probably due to the stone. They are quite crumbly if you hit them with the little chipping hammer. But it’s not that bad. Stuff from below, a bit of foam, a bit of sealing compound, then the insulation...
What worked well: screw and support a wooden board from below. Pour and compact the screed.
There it is again, the spray foam mafia :oops:
There was about a 5 cm gap between the dormer walls and the outer wall through which air was flowing. I went through about 15 cans (!) there. Now it’s sealed... at least according to an improvised blower door test using a kitchen hood: