Does ceiling insulation need a vapor barrier?

Fiberglass Insulation

In most climates, it needs a vapor barrier. Some builders rely on batts with attached kraft-paper facing to do that job, but Tom recommends unfaced batts, covered in plastic with all the seams taped shut.

Does ceiling need vapor barrier?

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.

Does all insulation need a vapor barrier?

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.

Does basement ceiling need vapor barrier?

If the basement is finished and has no moisture issues, the vapor barrier is not needed. If it has moisture issues, the vapor barrier is probably a problem.

Where does the vapor barrier go in a basement ceiling?

You want the vapor barrier on the oppsite side - the upper side of a basement ceiling. You can achieve that if you have, for example, sheet vinyl or something else that seals over the floor above. You are going to find that an inch of spray foam out of little cans will be quite costly.

Vapor Barriers: Need one or not?

What type of insulation should I use in my basement ceiling?

Your best option is insulating your exposed foundation walls. Start with getting any moisture issues under control, then use water-resistant insulation like closed-cell spray foam or XPS foam board. Most homeowners opt for fiberglass, but fiberglass has the chance of trapping moisture.

Do I need a vapor barrier for attic insulation?

Fiberglass Insulation

In most climates, it needs a vapor barrier. Some builders rely on batts with attached kraft-paper facing to do that job, but Tom recommends unfaced batts, covered in plastic with all the seams taped shut.

Should you put plastic between insulation and drywall?

Without poly beneath the drywall, water vapor hits the drywall and diffuses through to the drier (in summer) indoor air. By installing a sheet of poly there, you cut off that drying mechanism and water that finds its way into walls can stay there longer and do more damage.

Can you insulate attic ceiling?

A finished attic should be insulated much like the rest of the house, with insulation in the walls and ceiling. If your attic is already finished, it probably is at least partially insulated. However, most older attics are under-insulated so it's a good idea to raise the R-value where possible.

Is it OK to cover insulation with plastic?

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.

Does drywall act as a vapor barrier?

The permeance of unpainted drywall is very high, generally between 20 and 90, so it's not a vapor retarder at all. Meanwhile, air leakage through a 1 square inch hole in a sheet of drywall allows 30 quarts of water vapor to pass through the drywall under the same conditions. A third of a quart versus 30 quarts.

Does vapor barrier go before or after insulation?

After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Not every wall does. A vapor retarder is a material used to prevent water vapor from diffusing into the wall, ceiling or floor during the cold winter.

Where should vapor barrier be placed?

Vapor barriers are usually best installed on the side of the wall that experiences the hotter temperature and moister conditions: the inner surface in colder climates and the outer surface in hot, humid climates. In existing spaces, oil-based paints or vapor-barrier latex paints offer an effective moisture barrier.

Can you insulate interior ceilings?

In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, cathedral ceilings, floors over unheated garages or porches, knee walls, and in between interior walls—especially bathrooms—as well as ceilings and floors.

Can you use foam insulation on ceilings?

Spray Foam Is The Best Option To Insulate Your Ceiling

Even if you consider the cost it entails to insulate your ceiling with spray foam material, the benefits that spray foam has by keeping moisture and air out of the house will be more than enough.

Do vapor barriers cause mold?

One of the more common problems with crawl spaces that do not have a crawl space vapor barrier system is that they create high moisture levels, which may result in mold growth – as dampness creates the ideal environment for mold growth.

What is the difference between a vapor barrier and a moisture barrier?

Moisture barriers function to help in preventing water from entering inside of the wall cavity. On the other hand, vapor barriers basically prevent water vapor from the interior of the house to filter through the wall and condense on the warm side of the insulation.

Do you vapour barrier ceiling or walls first?

To start installing poly it does not really matter if you do the walls or ceiling first but I prefer to do the walls in a room first. So to do the walls start by deciding how big of a piece you can handle and cut if from the roll. I would start with about a 8 foot piece until you do one to make it easier.

Should I use faced or unfaced insulation in my basement ceiling?

Faced insulation is actually recommended on basement ceilings and ceilings in general. The covering or "face" of the insulation prevents it from falling out and trickling down into the basement air. This is especially advantageous if the insulation is made of fiberglass, which can harmful if it's ingested.

Should I insulate my basement ceiling of the basement is unheated?

If your basement functions as a living space and you have heating installed down there, basement ceiling insulation ensures you won't lose heat to the rooms above. This is important because heat rises. Improper insulation guarantees a loss of the bulk of the generated heat to the spaces above.

Should I insulate ceiling in finished basement?

It is important to note that most experts agree ceiling insulation is only a consideration when a basement will remain unfinished. If the basement will be a finished living space, then wall insulation will provide sufficient coverage.