I recently bought an older home that has concrete main walls, but the previous owner also built 2x4 interior walls. I know that typically, rigid foam boards are placed directly against the concrete, but that's not an option for me right now. I've come across a lot of conflicting advice regarding whether I can put rigid styrofoam between the 2x4 walls and seal it with spray foam. Some say this might lead to moisture problems. Can anyone provide some guidance?
2 Answers
I'm a bit confused about why rigid foam isn't going straight on the concrete. Have you thought about sealing and insulating the rim joist? That area usually lets a lot of air into the basement, so it might help with insulation overall.
One thing to keep in mind is that your home needs a fresh airflow. If you’re sealing the rigid foam, just ensure that you’re allowing air to circulate properly to avoid moisture issues.