Can I just use plastic as a vapor barrier?

Author: Ralph Dickinson  |  Last update: Monday, October 13, 2025

You can use plastic if you put polyethylene between your drywall and the wall studs. This way, you should get a tighter wall without trapping moisture inside the exterior walls. If you are framing out a below-grade basement, however, do not use plastic as a vapor barrier.

Can I use plastic as a vapor barrier?

Yes, covering your insulation with a vapor barrier plastic before installing drywall is crucial. It prevents moisture buildup that can lead to mold, rot, and even structural damage. A polyethylene vapor barrier also adds a layer of fire protection, making your home safer.

Can I use 4 mil plastic as a vapor barrier?

Our 4-mil plastic sheeting is a multipurpose film perfect for a wide variety of construction or DIY projects. This medium-duty plastic sheeting is commonly used as a vapor barrier in between insulation and drywall, used as a drop cloth or a temporary cover for equipment and supplies.

What can I use instead of a vapor barrier?

Drywall works too, and is pretty much the standard for this sort of thing. You could also use plywood or anything else that can act as an air barrier while still being vapor permeable to allow for some inward drying.

Is it okay to cover insulation with plastic?

One quick and effective way to cover exposed insulation is by using plastic sheeting. This method is simple and can be done with materials readily available at stores like Home Depot.

Vapor Barriers: Need one or not?

What is the best plastic for a vapor barrier?

The Top 5 Underlayments for Vapor Barriers
  • 8 Mil White/Black Dura-Skrim® Reinforced Plastic Sheeting.
  • 12 Mil White/Black Dura-Skrim® Reinforced Plastic Sheeting.
  • 20 Mil Dura Skrim® Reinforced Plastic Sheeting.
  • VaporBlock® Vapor Barrier.
  • PRO Crawl Barrier.
  • Vapor Barrier Tape.

Can you use plastic instead of Tyvek?

Plastic Degrades When Exposed to Repeated Heat

This is especially true of plastic sheeting installed under siding on south-facing walls. It's likely to become brittle in just a few years.

What happens if I don't use a vapor barrier?

Even if the concrete foundation is enough to keep water away from the building, water vapor can easily rise to the surface and damage a building's foundation, subfloor, and main floor. A vapor barrier is crucial to protect a building from the many negative effects of water vapor on building materials.

Is aluminum foil a good vapor barrier?

Aluminium foil is considered to be very resistant, tear- resistant and vapour diffusion-tight. A PE-aluminium laminated vapour barrier is particularly suitable for a vapour-tight construction.

What can be used as a vapour barrier?

There are a wide number of materials available to create effective vapour barriers, including:
  • Elastomeric coatings.
  • Aluminum foil.
  • Paper-backed aluminum.
  • Polyethylene plastic sheet.
  • Asphalt-coated Kraft paper.
  • Metallized film.
  • Vapour retarder paints.
  • Extruded polystyrene or foil-faced foam board insulation.

What is the minimum plastic thickness for vapor barrier?

Standard Crawl space vapor barrier thicknesses range from 6 mil to 20 mil, with 6 mil being the bare minimum and 20 mil being the most heavy duty and puncture-resistant.

Can I use painters plastic as a vapor barrier?

Encapsulation Vapor Barrier Thickness Matters. A typical painters plastic is 6-mil or less, and is usually only 0.5 mil. This type of plastic is used to create barriers between rooms. Water restoration companies will use 0.5 mil but many times use a 6-mil plastic to create containment areas.

Can you use black plastic for a vapor barrier?

Multi-Purpose - Our black plastic sheeting can be used as a moisture barrier, vapor barrier, protection barrier for painting, dust containment, spray barrier and more! This black sheeting plastic is great for covering and protecting lumber, equipment, and any type of machinery.

Is plastic a strong barrier protection?

Protective: Plastic can provide a holistic protective barrier better than other materials like metal, paper, or glass. Without this protective barrier, foods, beverages, and cosmetics may be exposed to more contaminants and other harmful elements like excess light and moisture.

Can I use 6 mil plastic for vapor barrier?

6 mils is the minimum thickness for vapor barriers. Most vapor barriers may range from 6 to 20 mils in thickness. Although 6 mil is the minimum standard, the crawl space environment may require a thicker material to effectively block moisture and gases.

Can water Vapour pass through plastic?

These ball-like chains present voids, where molecules will pass to go through the packaging's material. Obviously, these voids are not so big, so they will let more easily the littlest molecules pass, such as oxygen, water vapour, etc.

What can I use instead of vapor barrier?

Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor retarders are usually mechanically fastened and sealed at the joints.

Do you need vapour barrier with foil backed insulation?

With the insulation built into the plasterboard, there is no need for an additional installation process, saving time and money. One of the key benefits of insulated plasterboard is the option for foil-backed varieties, which serve as a built-in vapour barrier.

Why not to use aluminum foil?

It's best to avoid wrapping food in aluminum foil for extended storage, particularly for acidic or salted foods. Prolonged contact with moisture, acids, or salts an cause the foil to degrade, allowing aluminum to leach into the food. This can affect the food's taste and raise potential health concerns over time.

Is Tyvek a vapor barrier?

Is DuPont 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.

Is it OK to overlap vapor barrier?

Unless otherwise indicated by the design professional(s) of record, unfold the vapor barrier to completely cover the placement area. Overlap all joints/seams a minimum of 6 inches. Ensure the vapor barrier is clean and dry when applying a manufacturer's engineered seaming tape or approved method.

Can you use plastic as a moisture barrier?

A moisture barrier is a material that reduces moisture from moving through other materials. Therefore, a plastic sheet can be a vapor barrier. In fact, plastic (or polyethylene) sheets are a Class I vapor barrier. Meaning, in terms of excellent moisture control, a plastic sheet is one of the best options.

When should you not use a vapor barrier?

Because a vapor barrier is a low permeable barrier, it keeps moisture from passing through. This is beneficial to keep moisture away from a dry surface but will trap moisture behind it if installed on a water-damaged concrete wall, causing the wall to fail further.

Can you use Visqueen as a Vapour Barrier?

Visqueen Vapour Barrier is an ACVL (air and vapour control layer) and is used in medium condensation risk buildings to reduce the risk of interstitial condensation occurring within the structure as well as improving the airtightness of the building.

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