The thickness of spray foam really depends on where it’s being applied and what you’re trying to accomplish. Now generically speaking, we usually recommend open cell spray foam to be 6- to 10-inches on a roof deck or ceiling and 3-inches in the walls.

How thick should spray foam insulation be?

“Normally, what we teach is that all foam applications should be installed in 3/4-inch to 3-inch-thick lifts. If foam is applied thick and quick — say, 4 inches thick — you gain yield. You can cover more wall with less foam. But the foam will be less dense.

What is the R-value of 2 inches of spray foam?

Open-cell spray foam has an R-value of about R-3.7 per inch, while closed-cell spray foam has an R-value that may be as high as R-6.5 per inch.

What is the R-value of 4 inches of spray foam?

Open-cell spray foam has an R-value of 3.7 per inch, while closed-cell spray foam delivers an R-value of up to 6.5 per inch.

What is better open or closed cell insulation?

Closed cell foam has a higher R-value than open cell foam, usually about 6.0 per inch. This higher rating makes closed cell foam better at keeping heat in or out of a structure. Open cell foams have an R-value of around 3.5 per inch.

Is spray foam worth the investment?

Spray foam insulation is typically two to three times more expensive than cellulose or fiberglass insulation. Spray foam insulation does cost more than traditional options, but over time it pays you back in energy savings, and you can’t really put a price on the comfort of your family.

What is the R-value of 3 inches of spray foam?

What to use to seal gaps in attic insulation?

Expandable Foam Spray – get several cans of expandable foam spray to seal larger gaps (1/4 inch to 3 inches). Aluminum Flashing – this keeps the insulation from getting too close to the flue pipe, which can create a fire hazard.

Is it safe to air seal attic with vermiculite?

If you have vermiculite insulation in your attic, that’s bad news. The safest approach to attic vermiculite is to assume that the vermiculite contains asbestos. That means that you shouldn’t disturb it. Properly air sealing an attic with vermiculite insulation requires that the vermiculite be removed.

What kind of insulation do I need for my attic?

Insulation – you will need batt, roll, or blown insulation. Garbage Bags – fill the bag with insulation to insulate stud cavities under kneewalls and dropped soffits. Silicone or Acrylic Latex Caulk – use the right kind of caulk to seal any cracks or gaps smaller than ¼ inch.

Why do I have dirty insulation in my attic?

Dirty insulation is also a clear indication of some kind of air movement. If you see patches of dirty insulation in your attic, you probably have an air leak very close by. If you pull back the insulation, you should be able to see the cavity that was covered with insulation rather than sealed first.