Proper Foam Insulating From Soffit To Attic

Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic.

Proper foam insulating from soffit to attic.

Just getting to the soffits requires some dexterity. Install a minimum of 1 inch of spray foam insulation over the attic floor to provide a continuous air control layer. Verify that there is a baffle at each soffit vent extending from the top plate to above the height of the insulation to provide a pathway for ventilation air while keeping insulation out of the soffit vents. Earlier this year i got a question about a home that had spray foam insulation in the attic.

If you re finishing your attic insulating it to the proper r value can cause a dramatic loss of headroom if you limit yourself to fiberglass batts. It has been said that insulating with spray foam insulation at the roof line will lead to moisture problems with the roof sheathing. Insulation often clogs the space between the rafters blocking air from traveling to and from the soffit area. That will be a pain in our house because our roof has a shallow pitch.

The soffit vents are now installed but you still need to make sure there s no insulation blocking the new vents. If the attic is insulated with fiberglass batts just pull back any that are blocking the flow of air. If there s blown in insulation like ours rake back the fluffy stuff with a 3 or 4 ft long 1 x 6 or use a garden rake or hoe. Nothing unusual about that.

Foam blocks airflow needs no vapor barrier and has a higher r value per inch than loose fill or batts so you ll get more protection with less depth. Five common causes of poor attic venting. Install air chutes or clear them if they re clogged photo 1. With spray foam unlike with loose fill or batts you must cover the soffit vents they aren t needed to keep the roof cool.

Moisture is also another huge issue when it comes to spray foam insulation in an attic. As with attic floor insulation moisture and heat removal are the reasons for creating proper air. I ve researched this a bit and know that the recommended approach to seal off the soffit from the attic is to insert a square of rigid foam and spray foam over it. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits but then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.

To meet all three goals insulating your finished attic ventilating the roof and maximizing headroom use a combination of dense batt insulation rigid foam sheeting and air chutes.