Quick Answer: Can I Put New Vapor Barrier Over Old?

What is the thickest plastic sheeting?

Understanding Thickness of Plastic SheetingRatingThickness1 MIL0.001 inch3 MIL0.003 inch6 MIL0.006 inch9 MIL0.009 inchFeb 19, 2012.

Should vapor barrier be taped?

per foot is usually the best thing you can do to reduce crawlspace moisture. Cover the dirt crawlspace with a plastic moisture polyethylene vapor barrier. Overlap any seams and tape them. … This not only insulates the walls but also keeps rising dampness in the concrete from getting into the crawlspace.

How much does it cost to replace a vapor barrier?

Crawl Space Encapsulation Cost EstimatorStepsAverage CostInsulation Installation$1,000 – $3,000Vapor Barrier Installation$1,200 – $4,000Sealing Vents and Holes$150 – $450Dehumidifier Installation$1,500 – $2,5003 more rows

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.

Can you use a tarp as a vapor barrier?

Lay a heavy plastic tarp — 6 mil or thicker — over the entire area. If you must use multiple sheets, overlap them by at least 2 feet. Use stones to hold the plastic down. The plastic acts as a vapor barrier, eliminating much of the migration of water vapor from the ground to the crawl space.

Where do you put moisture barrier?

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.

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 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.

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.

Should you put plastic over insulation?

Without a vapor barrier in place, condensation inside the walls could ruin the insulation and promote the growth of harmful mold and bacteria. Plastic, specifically 6-mil polyethylene plastic, is the most commonly used vapor barrier.

Are vapor barriers bad?

Vapor barriers are supposed to stop vapor diffusion through roofs, walls, and floors. But they can also can trap moisture, causing rot and mold. Where moisture comes from: Water vapor can be forced into wall assemblies from the warm side of the house.

Should I put gravel in my crawl space?

In our opinion, placing gravel on top of the crawl space plastic is a bad idea. First, gravel on top of the plastic won’t work well. The gravel, especially sharp gravel, is more likely to puncture the plastic ground cover.

How important is vapor barrier?

A vapour barrier is an important component in building construction. Its purpose is to help prevent water vapour from reaching building walls, ceilings, attics, crawlspaces or roofs, where it can condense and cause building materials to rot or grow mould.

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.

Can you double layer vapor barrier?

That’s because that’s where the moisture is coming from. … If you do, you run the risk of creating a double vapor barrier; any moisture that passes through the first layer of insulation can get trapped by the vapor barrier on the second layer.

How long should a vapor barrier last?

20 yearsWhile thinner plastic or regrind may be okay for short-term use, only reinforced virgin poly should be used for long-term applications like crawlspace vapor barriers. Properly installed virgin reinforced poly should last 20 years or more in a crawlspace.

Where should I put the vapor barrier in my basement?

Not to be confused with a vapor barrier—which is placed on the warm side of the wall just in front of the insulation and behind the drywall— a moisture barrier goes against the basement wall and behind the insulation and framing. The best option for insulating a basement is to use spray foam insulation.

Can I use roofing felt as house wrap?

House wrap and felt paper, when properly installed and undamaged, are both weather resistant barriers (WRB) that create permeable and water- and air-resistant exterior walls. The main advantage of house wrap, over felt paper, is the superior strength and durability of house wrap.

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.

Should I remove old vapor barrier?

Ideally, you would remove the torn plastic. … When you can’t remove the old plastic, you can go ahead and cover it. Just be sure it doesn’t lead to too much excess material for the replacement. When you install a vapor barrier that has wrinkles or raised portions it is more vulnerable to tears.

Should I put a vapor barrier on my ceiling?

Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days. … Omitting a ceiling vapor barrier by arguing that “you have to let the moisture escape” or “because the house has to breathe out the top” is actually correct, in a way. It’s also incorrect, in a way.