Should You Put Plastic Over Insulation?

Where should vapor barrier be placed?

In order to prevent condensation from forming, a vapor barrier should be placed on the warm side of your insulation to stop warm, moist air from condensing on a cold surface inside your wall.

In cold climates like Canada, for most of the year the vapor barrier should be on the inside of the insulation..

Can I put new vapor barrier over old?

Our best practices are that the old vapor barrier is left in place and the new one is placed over it. The old barrier even if it does not cover the entire crawl space serves to provide some additional moisture blocking and also help protect your new vapor barrier from any rocks or debris on your crawl space floor.

Do I need vapor barrier behind Hardibacker?

You need to install a vapor barrier to the studs at the very least, and you must alway mud and tape the seams with fiberglass cement backerboard tape. Backerboard is water-permeable, and will not stop moisture from entering the wall cavity.

Do you put insulation behind shower walls?

The insulation behind the tub or shower should be equivalent to the insulation in the rest of the exterior walls and should be covered with an air barrier of cement backer board, rigid foam insulation, or non-paper-faced drywall that is sealed at the edges and seams to provide a continuous air seal.

Do you need a vapor barrier for attic insulation?

If you insulate the attic floor, it is also important to have a vapor barrier in place, to prevent warm, moist air from rising into the chilled attic from the living space below. The moisture will condense on the wood and insulation, reducing the insulation R-value and encouraging the growth of mold and mildew.

Do you need to put plastic over insulation?

Without a moisture-proof material to protect the insulation and framing within the wall, hot and cold battle, moisture forms, and mold and rot take advantage of the result. Install an unbroken sheet of polyethylene vapor barrier to prevent it from happening.

Can you cover insulation with plastic?

4 Answers. 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.

Do vapor barriers cause mold?

The Problem With Vapor Barriers The original reason for using vapor barriers was a good one: to prevent wall and ceiling assemblies from getting wet. … This can lead to significant moisture problems and mold; problems occur when walls get wet during construction or more often throughout the home’s life.

Can you put plastic over insulation in attic?

Once you talked about stapling down sheets of plastic over rolls of insulation. … In any case, a vapor barrier always faces the heated side, so it would never be put on top of batt insulation in an attic.

Is Tyvek a vapor barrier?

No, DuPont™ Tyvek® is not a vapor barrier. It is made with unique material science to keep air and bulk water out while allowing moisture vapor inside walls to escape.

Can you cover attic insulation with plywood?

Once the insulation is down, you can turn your attic into valuable storage space by covering the floor with plywood. It will also make the attic a safer place in which to walk.

Should I put plastic over insulation before 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.

Does drywall insulate?

Drywall is considered a suitable construction material for interior walls, but its primary purpose is not to insulate. To make a significant difference in heat flow transfer, you must include insulation along with the drywall installation.

Do I need a vapor barrier over my 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.

Can I use plastic sheeting as a vapor barrier?

In simple terms, a vapor barrier is a material that won’t allow moisture to pass through it, such as plastic sheeting. … It’s designed to stop the moisture before it can enter the wall cavities. There are two basic types of vapor barriers used with exterior wall insulation. The most common is paper-faced insulation.