Joseph Lstiburek On Using Foam Insulation Under Attics

Lstiburek says that the moisture that causes these problems is stored in the roof sheathing and in the foam itself.

Joseph lstiburek on using foam insulation under attics.

Near term the moisture content of the roof sheathing b. Of unvented roofs by more than 50 percent and allow the use of dense pack cellulose in retrofit applications without risk. Joseph lstiburek is the founding principal of building science corporation. Spray foam insulation evokes some interesting conversation among building scientists construction professionals environmentalists and homeowners who have it in their homes.

Spray foam insulation under the roof deck the amount of spray foam insulation and its water vapor transmission is climate dependent. 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. Joseph lstiburek talks about the not so controversial ways to maximize the efficiency and airflow of your roof and attic. This can be done with pretty much any rigid insulation.

Lstiburek s commitment to advancing the building industry has had a lasting impact on building codes and practices throughout. The moisture is stored in the sheathing and the foam. I m going to start off by saying what might seem controversial but really shouldn t be. Joseph lstiburek founding principal of building science corporation responds.

Earlier this year i got a question about a home that had spray foam insulation in the attic. Foam insulation above the roof deck to keep its temperature above 45 f throughout the year or spray foam insulation under the roof deck to keep interior moist air from contacting it. Code change allowing use of air permeable insulation in the construction of unvented conditioned attics. Closed cell spray foam can be used in any climate.

Spray foam insulation is more expensive than batt insulation and needs to be expertly installed to prevent missed areas or pockets that can reduce the efficacy of the building envelope. It has the highest r value of any insulation material is a vapor retarder and provides a tight air seal. Joe lstiburek a principal at the building science corporation is a frequent public speaker. Poor workmanship during attic and roof installation will result in expensive callbacks and repairs as insulation will have to be replaced.

Moisture laden air ends up in the attic due to this zhygric buoyancy. On december 5 2012 lstiburek presented an educational session on spray polyurethane foam at the building science experts session in westford massachusetts. I would recommend insulating on the exterior. Nothing unusual about that.

In your climate zone zone 5 code requires you to insulate concrete block and other mass walls to at least r 13 if all of the insulation is on the exterior.