Do Attics With Spray Foam Insulation Need Ventilation

Tell them the attic is to have no ventilation of any type.

Do attics with spray foam insulation need ventilation.

Because basically now that attic is a conditioned space. They know roofing materials underlayments flashing and attic ventilation. But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents. However in a traditionally insulated attic insulation on the ceiling the attic is vented.

Therefore providing mechanical fresh air ventilation is especially important in spray foam houses. Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e. Moisture is also another huge issue when it comes to spray foam insulation in an attic. Do attics with spray foam insulation need ventilation.

Attic ceiling to stop airborne moisture from reaching a cold surface and condensing inside the building envelope in this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within. We also recommend to do no harm when we. One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic. When we seal the attic with spray foam it s as tight as a butter tub.

The ventilation helps to keep the air fresh in the home the insulation stops warm air from escaping and cold air from leaking in. Sometimes humidity levels spike in an attic after a spray foam job. It has been said that insulating with spray foam insulation at the roof line will lead to moisture problems with the roof sheathing. If a blower door test reveals that your spray foam insulation reduced ventilation beyond an acceptable level you may need to install one of these units in your home.

I have a spray foamed attic. High attic humidity often results from spray foam insulation. Nothing unusual about that. They need the right level of ventilation but they also require insulation in order to help improve the energy efficiency of the property.

Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits. Some know more than others of course but you should probably assume the worst any time a roofer comes to your spray foam insulated home. Nope you absolutely do not need to ventilate a spray foam house and here s why.