Should a vapor barrier be installed in attic?
In hot-dry climates a vapor retarder should also not be installed, but attics can be vented. All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate.
Where does the vapour barrier go in the attic?
If the attic retrofit is being completed in conjunction with interior renovations, the easiest approach is to install a new, single air and vapour barrier on the underside of the ceiling joists.
Why is there no vapor barrier in the attic?
Even though we apply vapor barriers to exterior insulated walls in cold climates it’s no longer recommended for ceilings (floor of the attic). Because it’s nearly impossible to seal penetrations in the ceiling, the reality is water vapor will get into the attic.
Can you put plastic over insulation in attic?
Plastic isn’t recommended in this situation because it would create a second vapor barrier that can trap moisture and result in condensation and mold. Craft paper would have the same problem, this is what is most likely on the other side of the insulation for the vapor barrier you want.
Can you staple vapor barrier?
Tug and smooth the vapor barrier to ensure a completely smooth surface lacking wrinkles or gaps through which moisture and air may escape, defeating the vapor barrier’s purpose. Staple through the plastic into the sole plate — the horizontal board running under the studs – at bottom.
Do I need a vapor barrier in my ceiling insulation?
Vapor Blockers Vapor barriers—sheets of plastic or kraft paper—keep water vapor out of the wall cavity, so the insulation stays dry. Not every type of insulation needs a vapor barrier. But if it does, the barrier should face inside in northern, heating climates, and outside in humid southern climates.
Can I put boards over attic insulation?
An attic can be floored with 1/2″ CDX plywood, if it is being used only for storage. However, the same can’t be said if you are planning on using the space as a living space. In that case, you will need to use 3/4″ thick plywood. As an alternative, 3/4” OSB can be used.
Is OSB OK for attic floor?
If your attic joists won’t bear the weight necessary to finish out a living space but the engineer cleared them to support floor decking for light storage, you can install ½-inch plywood or oriented strand board (OSB) in 4-foot-by-8-foot panels over existing 16-inch OC joists.