Closed Cell Foam Vs Open Cell Foam Attic

Calculating spray foam costs.

Closed cell foam vs open cell foam attic.

Closed cell foam for insulation applications range in density from 1 7 lb cu. Open cell foam is weaker or softer feeling than closed cell foam but a much better sound barrier than closed cell due to the open nature of the cells. Ft of foam material is weighed. Many builders in cold climates use closed cell spray foam instead because of its lower water vapor permeability which means it doesn t need the extra step of installing a vapor retarder.

Open cell tends to be roughly 0 5 lb cu. A foams r value is its resistance to heat flow or in other words how well they insulate. Closed cell foam can be over three times that with a density of 1 75 pounds per cubic foot or more. To ascertain foam density one cubic foot cu.

This makes the foam weaker or softer feeling than closed cell foam. Open cell foam has an r value of about 3 5 to 3 7 per inch while closed cell foam has an r value of about 6 per inch. Closed cell foam can also increase the racking strength of attic walls which. Roofing applications typically use a 2 8 to 3 0 lb cu.

Open cell spray foam insulation needs to be at full thickness before it can act as an air barrier. It is either open cell foam where the tiny cells of the foam are not completely closed. To support traffic and loads better. Closed cell foam is roughly four times as dense as open cell for insulation applications.

Open cell has an r value of 3 7 and closed cell has an r value of 6 5 based per inch of installed spray foam. The insulation is blown into the wall or attic one layer 1 at a time. It s expanding properties ensure that it covers every little crack and hole but even with that ability it still needs to be installed correctly. Closed cell foam differs in that all of its tiny foam cells are closed and packed together.

But open cell spray foam with a vapor retarder can work too. Closed cell foam is much denser than open cell foam. In density or even higher for certain applications. Closed cell spray foam insulation acts as an air barrier at any thickness due to its solid properties.

Open cell is not a water barrier it will hold moisture if exposed to the outside environment. If you need an air barrier as part of your installation closed cell is a better choice. In density whereas closed cell ranges from 1 7 to 3 0 lb cu. They are broken and air fills all of the open space inside the material.