I have a brand-new home in Miyagi, Japan (38N), a temperate climate with hot, damp summer seasons and winters with nights around 0 to -4 C (32F to 25F).
I ventured under your home through the concrete crawlspace for the very first time as I wished to lower energy losses through the floor if possible and enhance convenience. (It’s respectable overall as is).
There are foam boards (StyroAce II) under a vapor barrier under plywood under cedar floorboards. The crawlspace is unconditioned concrete aerated at the border.
Questions:
1. There are large holes in the insulation where pipes go through. There might not be air leak as it seems to be filled with spray foam.
Would it be beneficial to add expanding sprayfoam here to change that which was removed?
2. The thermal imaging reveals bridging through the joists (as expected). From beneath there are gaps between the foam and joists (likely as wood agreements in the winter season.)
Would there be value in covering the exposed joists with a thin strip of foam insulation. How to adhere- tape to the surrounding foam boards as they’re about at the same level or in some way glue or mechanically connect to the wood above?
Additionally would it be worth it to try to add another layer of foam to totally cover the existing foam boards and joists (a lot of work as all products need to fit through a fairly narrow access hatch). How would you adhere the foam because case?
Alternatively, if you would not do the above methods would you attempt caulking or taping to eliminate the spaces in between wood and foam board?