My brother has just bought a house and wants to turn the basement into a workout room. However, I'm unsure about the best way to approach insulation, particularly since we've noticed signs of past water damage. The basement is located in a bowl at the bottom of a hill with some flaking stucco on the walls, indicating moisture problems. He's set up a dehumidifier, but I'm questioning if insulation is a wise choice or if it will just trap moisture. I've come across mixed advice about leaving gaps between the framed and cement walls, using rigid foam insulation directly, and whether or not to include a vapor barrier. Considering the electric heat in New England's cold winters, I also wonder if not insulating will lead to unnecessary heating costs. What should we do?
2 Answers
I personally would suggest taking your time with the insulation. Maybe set up the workout gear in the area he wants and live with it for a bit. Observing how the basement handles moisture over six months can give you a clearer picture. That way, he can see the temperatures and watch for any leaks before committing to walls.
First things first, you need to address the moisture issues before any insulation work. Focus on grading, gutters, and ensuring proper drainage. After that, it's generally a good idea to use rigid foam against the concrete wall—make sure to tape and seal it well. Skip the vapor barrier; it can trap moisture and lead to mold problems in the long run.
Definitely a good point! He might resist the sitework due to costs, but preventing future damage is worth it. I’ll help him with the gutters since the house has that basin issue.

That's really solid advice! My brother tends to rush into things, but I think waiting might be smart, even if he doesn't like it.