Do You Need Attic Ventilation With Spray Foam Insulation

Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space.

Do you need attic ventilation with spray foam insulation. Earlier this year i got a question about a home that had spray foam insulation in the attic. Nope you absolutely do not need to ventilate a spray foam house and here s why. I have a spray foamed attic. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof.

However in a traditionally insulated attic insulation on the ceiling the attic is vented. Sometimes humidity levels spike in an attic after a spray foam job. Moisture is also another huge issue when it comes to spray foam insulation in an attic. 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.

Nothing unusual about that. Therefore providing mechanical fresh air ventilation is especially important in spray foam houses. The main aim of ventilating the attic space is to allow the air in the home to circulate. But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.

All insulation materials require proper venting. Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic. Rigid foam and spray foam are two of them. High attic humidity often results from spray foam insulation.

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. Ventilation is required but not all ventilation options are appropriate for the home or homes with spray foam insulation. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits.

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. It s terrific because it s pretty much the same temperature as the rest of the house all the time.