Vapor Barrier Roof Rafters

Whether or not you need a vapor retarder hinges on three main factors your climate your home and the location of the wall you re insulating.

Vapor barrier roof rafters.

A roof design that includes an adhered roof membrane with multiple layers of insulation with board joints offset and staggered over a vapor retarder air barrier helps lower the risk that air and the moisture it carries will infiltrate the roof system. Not flammable but it must be protected with wallboard. Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer. The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.

In circumstances where conditions inside a home or office are much different than outdoor conditions water. But it seems the. White bubble between roof and rafters. To know if you need a vapor retarder ask yourself a few basic questions.

We have some moisture issues that i will address at a later time but i d like to install a vapor barrier on the underside of the 1st floor subfloor as well as insulation. My question is should iuse a vapor barrier inthe attic floor. That reduction of air and moisture infiltration can then help improve roof longevity. Vapor barrier on under side of floor joists over a crawl space oct 26 2011 alex in seattle said.

A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. I have a 1961 single story home with a cement floor crawl space. From what i ve read online it seems wise to install a vapor barrier over the plywood to prevent condensation from getting absorbed into the plywood from the steel roof. I thinking walls 1 closed cell then blow in followed by vapor barrier and steel panel.

Rosemary june 5 2015 at 3 03 pm. Not recommended for exterior below grade applications. 4 times the cost of fiberglass batts. There are certainly other options.

No wrap on walls. Resolution of the vapor barrier debate. That is create a vent channel above the insulation with low and high vents. Most authorities now agree that vapor barriers are important under certain conditions but not necessarily as a whole house solution for every home.

Whether or not you use vapor retarder you want an air tight air barrier such as well sealed drywall to keep out moisture from the house. The previous owner has 1 foam insulation with a a plastic vapor barrier only on the rafters of the roof about4 from the slate roof but not on the walls of the attic. Hopefully you have installed a vapor barrier between the roof purlins and the roof steel. Plan is to after foam put barrier and steel panel up and then.