Warning about spray foam insulation in our cold winters

I had a guy from a local Edmonton company install spray foam in my attic about two years ago, and he came back for a check-up last fall. He pointed out that I hadn't left enough of a gap between the foam and the roof sheathing, which is a big deal here because of our temperature swings. He basically said, 'In this climate, you need that air space to let any moisture escape, or you're asking for rot.' I had just let them foam right up to the wood, thinking more insulation was always better. So, I had to pay to have a small section cut back and re-done, which cost me around $400. It was a real 'oh, right' moment because I was so focused on the R-value that I ignored the building science part. Now I always ask contractors specifically about vapor barriers and air gaps for our weather. Has anyone else had to fix a spray foam job because of moisture worries?

2 comments

2 Comments

mason41712h ago

That line about "the premium price for learning" really hits home. It feels like half of home ownership is paying for the lesson after the fact, because you trusted the expert in front of you. I see this everywhere now, from quick kitchen remodels to car repairs, where the easy, fast fix ignores the long term problem it will create. We get sold on the immediate benefit and miss the bigger picture.

cameron77022h ago

So you paid a guy to mess it up, then paid him again to fix his own mistake? Classic. I guess that's the premium price for learning that more foam isn't always the answer, just a fast track to replacing your roof deck.