One of the biggest benefits of open cell foam is that it expands so much after it has been applied, meaning it can insulate hard to reach nooks and crannies in a home. These types of areas can be hard to insulate with closed cell foam. Open cell foam is excellent for soundproofing where a single application can completely fill the area between studs.
If the crack is in your ceiling hot air in the attic can draw/suck cold conditioned air out. It happens through a natural principle of science call convection.
I’ve lost count of the number of homes I’ve inspected that have folding stairway built into the hallway or laundry room ceiling. More often than not the folding legs are not trimmed to the correct length or properly secured to the framing.
Installing rigid foam on the outside of a house is a great way to double the R-value and eliminate air leaks. Large sheets of foam insulation, screwed and sealed to the walls or roof, can cover or replace conventional sheathing and create a continuous barrier to heat loss or gain—something you don’t get with cavity insulation alone. We wrapped the house in this video with 4 inches of polyisocyanurate in two staggered 2-inch layers. This thickness strikes a balance between ease of installation and maximum R-value. If the foam is any thicker, it’s hard to hit studs when driving screws. Plus, combined with 5-1/2 inches of cellulose in the stud bays, 4 inches of rigid foam brings the wall up to a respectable R-40.