Rim Joist Insulation - To spray or not to spray

I’m thinking of insulating the rim joists in my basement. My home is about 100 years old, and I have a lot of air leaks. I’ve done the obvious weatherstripping around the home, but I think I need to do more to stop infiltration. Unfortunately, I don’t have attic access, so that’s not a possibility at the moment. So I’m thinking about tackling the basement. It’s very cold down there in the winter, which is making it hard to keep the first floor warm and comfortable. We replaced the single pane windows in the basement, for starters, but there’s still a lot of room for improvement!

I’m thinking of doing this myself. But I’m torn between rigid foam with caulk/expanding foam to seal it versus spray-in foam. Neither of them seem like rocket science. And I’m pretty good at following directions.

The one reason I would lean toward the spray foam is that several of the spaces are oddly shaped and partly blocked by ducts, pipes, or random boards. I’m not sure how I would maneuver a rigid piece of foam board in there. But, on the other hand, the spray foam sounds like a messy job.

Has anyone done this? Do you have any advice? Is one method more foolproof or markedly cheaper than the other?

Thanks, in advance, for any ideas!

Mike Holmes on Holmes on Homes always uses spray insulation as it completely seals out drafts. You can catch the series on HGTV right now in the US.

check your local building code, foam (rigid or spray) needs to be install with a fire block, if a fire started in your basement it could fill your house with toxic fumes quickly.

i would caulk the sill first.

rigid foam is an easy install. maybe fiberglass blanket in front of it would serve as fire block then could use any cosmetic covering as opposed to a fire blocking covering.