Proper Foam Insulating From Soffit To 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.

Proper foam insulating from soffit to attic.

Earlier this year i got a question about a home that had spray foam insulation in the attic. Baffles establish a channel for air to circulate between the insulation and the roof sheathing. Then cover the foam with drywall as required for fire safety. 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.

If the attic is insulated with fiberglass batts just pull back any that are blocking the flow of air. Insulation stops also known as attic baffles or rafter vents are designed to provide adequate air flow from the soffit vents to the gable or ridge vents in a home s attic. Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic. Moisture is also another huge issue when it comes to spray foam insulation in an attic.

With spray foam unlike with loose fill or batts you must cover the soffit vents they aren t needed to keep the roof cool. 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. As with attic floor insulation moisture and heat removal are the reasons for creating proper air.

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. Nothing unusual about that. In terms of product batt insulation will be different than blown insulation which will be different than spray polyurethane foam insulation.