By amanda wooley mar 23 2020 indoor air quality odor removal vocs did you know that the united states federal housing authority recommends that every home has a minimum of at least 1 square foot of attic ventilation for every 300 square feet of attic floor space.
Do attics with spray foam insulation need ventilation.
I am building a 2 500 sf house installed on wooden piers 2 ft off the groung.
Do attics with spray foam insulation need ventilation.
It will have pine siding metal roof and double paned windows.
Here s the answer to the question posed in my article title.
We also recommend to do no harm when we.
Yes using spray foam we have added your attic to the conditioned space.
Nope you absolutely do not need to ventilate a spray foam house and here s why.
As such it would seem venting the attic would increase the potential for condensation.
In many they don t get that far.
Or as we say in building science a house is a system.
Do you need attic ventilation with spray foam insulation.
However the opposite is true when the attic floor is air sealed and insulated.
As such he does not plan to install a ridge vent whirly birds soffit vents or gable vents.
Because basically now that attic is a conditioned space.
However in a traditionally insulated attic insulation on the ceiling the attic is vented.
It s nice that the spray foam insulation contractor recognized the need for combustion air in that case.
Therefore providing mechanical fresh air ventilation is especially important in spray foam houses.
Even when outside air is hot and humid if the attic space is air sealed from the interior it is much hotter than outside air.
Mechanical ventilation systems allow a constant flow of outside air into the home and can also provide filtration dehumidification and conditioning of the incoming outside air.
The ventilation helps to keep the air fresh in the home the insulation stops warm air from escaping and cold air from leaking in.
When we seal the attic with spray foam it s as tight as a butter tub.
I have a spray foamed attic.
My framing contractor recommends use of foam spray insulation instead of fiberglass insulation.