Most open cell foam has a density of about 5 pounds per cubic foot.
Closed cell vs open cell foam in attic.
As a result in iecc climate zones 5 and higher building codes require the use of a vapor retarder if you install open cell spray foam.
Id go with closed cell.
Open cell is more susceptible to mold and mildew but its expanding so it can hermetically seal an area.
Closed cell foam can also increase the racking strength of attic walls which.
But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.
A foams r value is its resistance to heat flow or in other words how well they insulate.
Closed cell spray foam insulation acts as an air barrier at any thickness due to its solid properties.
Open cell foam is used in a wide range of applications such as for noise reduction in sound rooms home insulation metal buildings under roof deck for semi conditioned attics and more.
Open cell spray foam insulation needs to be at full thickness before it can act as an air barrier.
Seems like you wouldnt want to seal something susceptible to mold growth but maybe thats just me.
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.
Open cell foams typically weigh in at 0 4 to 0 5 lb cu.
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.
This makes the foam weaker or softer feeling than closed cell foam.
Closed cell foam is much denser than open cell foam.
Roofing applications typically use a 2 8 to 3 0 lb cu.
Closed cell foam differs in that all of its tiny foam cells are closed and packed together.
To support traffic and loads better.
Closed cell is denser better insulating.
It is either open cell foam where the tiny cells of the foam are not completely closed.
They are broken and air fills all of the open space inside the material.
Closed cell foam can be over three times that with a density of 1 75 pounds per cubic foot or more.
Closed cell foam for insulation applications range in density from 1 7 lb cu.
A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits.