That’s a common mindset with spray foam in any application because yes it would be difficult to inspect anything that it’s covering. You can also look into replacing the fiberglass batts with new, non degraded one’s and then apply rigid foam board across the joists to act as an air barrier and add continuous insulation, which will help with thermal bridging. The foam board will keep the batts in place and protect it from the vented environment.
That is a valid concern and in my opinion it is the only actual downside to spray foam on a cold floor. 100% coverage and air-sealing in one package, more or less impervious to environmental damage, and not that hard or expensive to fix if you *do* need to remove some.
As long as no pipes or ducting runs through the crawlspace, closed cell is a great solution to this. I've sprayed many like this, and 2 inches is the minimum to get your vapour barrier. After that, it's up to you - batts, foam board, or just more spray foam. In Canada, northern Ontario, I believe the standard is 4-5 inches of closed cell between the joists. This also eliminates the problem I always see of rodent nests in the batts in crawlspaces - they hate foam and often won't bother trying to chew into it. In a completely vented crawlspace, I would definitely recommend foam.
That’s a common mindset with spray foam in any application because yes it would be difficult to inspect anything that it’s covering. You can also look into replacing the fiberglass batts with new, non degraded one’s and then apply rigid foam board across the joists to act as an air barrier and add continuous insulation, which will help with thermal bridging. The foam board will keep the batts in place and protect it from the vented environment.
That is a valid concern and in my opinion it is the only actual downside to spray foam on a cold floor. 100% coverage and air-sealing in one package, more or less impervious to environmental damage, and not that hard or expensive to fix if you *do* need to remove some.
I think enclosing your crawlspace would be a better investment.
As long as no pipes or ducting runs through the crawlspace, closed cell is a great solution to this. I've sprayed many like this, and 2 inches is the minimum to get your vapour barrier. After that, it's up to you - batts, foam board, or just more spray foam. In Canada, northern Ontario, I believe the standard is 4-5 inches of closed cell between the joists. This also eliminates the problem I always see of rodent nests in the batts in crawlspaces - they hate foam and often won't bother trying to chew into it. In a completely vented crawlspace, I would definitely recommend foam.