The R-value is a score for how well insulation keeps heat from passing through it; spray foam has a high score, especially closed-cell foam, which scores around 6 to 7 for each inch of thickness.

Yes, for a short time after it’s put in, spray foam can give off gases. It’s important to stay away until it’s safe, which usually takes about a day.

Closed-cell foam is denser and better at blocking water and air, while open-cell foam is softer and more breathable, good for filling nooks and crannies.

It’s not recommended; putting in spray foam can be tricky and if done wrong, it can be unsafe or not work well.

Both can be good for saving energy; the attic helps with keeping the whole house warm or cool, and the basement helps if you have cold floors or problems with pests like mice.