Lstiburek Roof Venting

In a cold climate the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned.

Lstiburek roof venting.

Joseph lstiburek talks about the not so controversial ways to maximize the efficiency and airflow of your roof and attic. Ordinary gable roofs don t have vents in the roof plane. By joseph lstiburek issue 221 so much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus. Building scientist joseph lstiburek explains when to vent your roof when not to and how to execute each common roof venting approach successfully.

These are the soffit vents. In iecc climate zones 4 and 5 some. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck. These are the ridge vents.

Historically roof assemblies have not contained enough insulation. In the moisture control handbook joe lstiburek explains why venting a roof may have worked better in the past. Roof wrecking ice dams aren t the only reason to make sure a roof is properly vented of course. Joseph lstiburek s article a crash course in roof venting has a section that quickly explains why roof venting matters.

Joe lstiburek notes that you can use gable vents instead of a ridge vent if you want but you still need soffit vents as air intake locations. The usual exit points are at the ridge. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. Ventsure 4 foot strip heat moisture ridge vent.

Roof slope is important. So heat loss from the conditioned space has warmed the attic area. 27 lineal feet required. Lstiburek s rules for venting roofs.

I live in new england where ice dams are a common problem which is to say improper roof venting is a common problem. The approach works for both cellulose and fiberglass in iecc climate zones 1 2 and 3 without limitation. The usual intakes are located in the soffit. Climate limit is likely iecc climate zone 5 for new houses.

Vapor transmission of vent film needs to be higher than expected greater than 50 perms. It comes on an easy to install flexible mesh roll and is hand nailable with no complicated fitting wrapping nail gun adapters.