Do You Need Attic Ventilation With Spray Foam Insulation

Ventilation is required but not all ventilation options are appropriate for the home or homes with spray foam insulation.

Do you need attic ventilation with spray foam insulation.

But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents. Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space. Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic. Therefore providing mechanical fresh air ventilation is especially important in spray foam houses.

Sometimes humidity levels spike in an attic after a spray foam job. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits. It s terrific because it s pretty much the same temperature as the rest of the house all the time. Nothing unusual about that.

Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home this can lead to health problems. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof. A combination of air sealing and insulating the attic floor while providing ventilation considerably reduces potential for condensation as warm moist air is less likely to enter the space and condense on cold surfaces. Nope you absolutely do not need to ventilate a spray foam house and here s why.

However in a traditionally insulated attic insulation on the ceiling the attic is vented. I have a spray foamed attic. High attic humidity often results from spray foam insulation. All insulation materials require proper venting.

When we seal the attic with spray foam it s as tight as a butter tub. It has been said that insulating with spray foam insulation at the roof line will lead to moisture problems with the roof sheathing. Earlier this year i got a question about a home that had spray foam insulation in the attic. Because basically now that attic is a conditioned space.

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. Moisture is also another huge issue when it comes to spray foam insulation in an attic.