A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.
Vapor barrier roof rafters.
Rosemary june 5 2015 at 3 03 pm.
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.
Resolution of the vapor barrier debate.
Hopefully you have installed a vapor barrier between the roof purlins and the roof steel.
Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer.
Not recommended for exterior below grade applications.
I have a 1961 single story home with a cement floor crawl space.
No wrap on walls.
White bubble between roof and rafters.
I thinking walls 1 closed cell then blow in followed by vapor barrier and steel panel.
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.
You could insulate the roof the traditional way.
Most authorities now agree that vapor barriers are important under certain conditions but not necessarily as a whole house solution for every home.
Vapor barrier on under side of floor joists over a crawl space oct 26 2011 alex in seattle said.
That is create a vent channel above the insulation with low and high vents.
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.
My question is should iuse a vapor barrier inthe attic floor.
In circumstances where conditions inside a home or office are much different than outdoor conditions water.
Not flammable but it must be protected with wallboard.
That reduction of air and moisture infiltration can then help improve roof longevity.
The insulation fiberglass or cellulose is then placed on top of the drywall with no vapor barrier above or below.
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.
4 times the cost of fiberglass batts.
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.
There are certainly other options.
Plan is to after foam put barrier and steel panel up and then.
But it seems the.
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.
