I'm currently working on my unconditioned basement and considering insulation options. I know my cinder block walls need insulation, but it's quite expensive to do it right with XPS on the block and framing everything out. Instead, I'm thinking about just installing mineral wool in the ceiling cavities, particularly where the bathroom and bedrooms are located above. I've already sealed the rim joist with 2" XPS and Rockwool. Here are my questions: Can I leave the mineral wool exposed? I'm worried that foot traffic above might disturb it and cause particles to fall. Is it safe to leave it, considering the basement can get a bit humid at times? And if I need to cover it, what's the simplest way to do that without trapping moisture? I was thinking about using 6mil poly, but I'm concerned it may create a moisture barrier.
2 Answers
I did something similar, and I haven't seen any mold issues. Just wanted to share my experience!
You could definitely cover it with Tyvek housewrap. It allows moisture to escape without letting air in, which is perfect for your situation! Also, consider using a dehumidifier or extending your downspouts to keep rainwater away from your foundation. That could help manage the humidity levels too!
That sounds like a solid plan! I also found some fire retardant 6mil poly sheeting. Do you think that could work well for my needs?