Switched from spray foam to rigid foam for my basement Reno

Always thought spray foam was the only way to go until my buddy who does commercial work showed me how easy rigid foam is to cut and seal. Saved about $400 on my own job in Edmonton last month and it's just as good for R-value. Anyone else made the switch and regretted it?

3 comments

3 Comments

miam751mo ago

Oh yeah, I actually just read a blog post from a building science guy about this! He said rigid foam is actually better in some basements because it doesn't trap moisture against the concrete like spray foam can if it's not done perfectly. I think people get scared about air gaps with the sheets but if you tape the seams right it's pretty tight. Plus you can do it yourself without renting a rig or paying a crew which is huge. My neighbor did his whole basement with the foil faced stuff and it's been great for two winters now. I bet you're gonna be happy you saved the cash and still got good insulation out of it.

anderson.david1mo ago

You're saying it's "been great for two winters now" but that's barely a test run... real issues like moisture or rot take way longer to show up. I'm with @miam75 that foam can be tricky but I'd want to see how it holds up after five or six years before calling it a win. Maybe it's fine, maybe it's not... I'd just wait a bit before recommending it to everyone.

thomas_martinez1mo ago

Oh man I'm totally with you on this! That "barely a test run" logic drives me crazy (people act like two winters is nothing when really if a setup is gonna fail you'd see it within the first season or two anyway). Moisture problems don't wait five years to show up - if you have a leak or vapor issue it'll show in the first freeze-thaw cycle. And here's the thing about rigid foam vs spray foam that nobody talks about enough: rigid allows for a real air gap behind it if you furr out the wall right, which gives moisture a path to drain. Spray foam bonds directly to the concrete and if that concrete has any dampness (which it almost always does in Edmonton clay soil) you're just trapping that moisture inside. I actually read a comparison from a building science guy in Minnesota who tested both after ten years and the rigid foam assemblies had way fewer rot issues because they could dry out. Plus the DIY savings are real - I'd rather spend that $400 on good tape and proper sealant than on a spray foam crew who might miss a spot anyway.