Finishing My Basement - Insulation Questions
Hello everyone. I stumbled across this site because I’m doing some research before starting to finish my basement. I’m glad I did there is a lot of good info here.
Anyway, I wanted to get opinions on my basement finishing plans – at this point mostly the insulation plan… Dana please chime in :)
First, some background. I live in Columbus, Ohio. My house was built in 2010. I have a cinder block foundation/basement walls. I have a Tremco barrier solution on the exterior and (I think) 1" of the Tremco WARM-N-DRI insulation on the exterior (below ground only). The builder claims I have R5 on the exterior.
I've read the Building Science stuff like 100 times but I just want to get opinions. So here is my plan:
Floors: I would like to keep the subfloor height to around 1.5” total so I can either use 3/4” XPS and 3/4” OSB or 1” XPS and 5/8” OSB. Are either a viable option? I was planning on taping the XPS seams on the floor. I was not planning on using a sheet of poly on the concrete floor. Thoughts? I will probably be using carpet as the finish floor in most of the area, but may use some cork flooring also.
Walls: I keep going back and forth on this option. I originally was thinking 1.5” XPS because it’s a bit less expensive than 2”. But now I’m wondering if I can get away with 1” since I have R5 on the exterior. Whatever I choose the seams will be foam sealed and taped (or is there a better, less expensive way to seal joints?) Up against the XPS I was going to frame out the wall and fill the stud cavities with R13 unfaced fiberglass insulation. Thoughts on 1.5” XPS vs 1” XPS?
Rim joists: I was planning on using pieces of 2” XPS and foam sealing the edges.
I think that’s all my questions for now. Please let me know what you think. Thanks in advance for any feedback. It will be greatly appreciated as I've been driving myself crazy with this stuff.