Should I cover my insulation with plastic?

Author: Alex Braun  |  Last update: Saturday, May 23, 2026

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.

Should you install plastic over insulation?

Big no-no! Plastic traps moisture, which can cause mold in your attic. Insulation needs to breathe. Think of it like a sweaty sweater under plastic - not comfy!

Does insulation need to be covered?

Fiberglass insulation needs to be covered in any occupied area of the home because it can enter the air and end up in your eyes, lungs and skin. If you have exposed fiberglass insulation in a common area of your home, you need to cover it — but drywall isn't the only solution.

Should you cover attic insulation with plastic?

Definitely do not add a plastic barrier between insulation layers. And as suggested above, make every effort to seal any openings where warm moist house air can leak into the attic. Vents, chimneys, wiring holes, etc. And do not cut off attic ventilation during the winter.

What do you put on top of insulation?

In general, either batt or rolled insulation or blown loose-fill insulation (fiberglass or cellulose) can be installed on top of old insulation.

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What do you put over 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.

What to cover exposed insulation with?

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.

Is it OK to cover attic insulation with plywood?

Can I put plywood over insulation in the attic? Yes you can install plywood subflooring directly over the floor joists and insulation on your floor. You need to install rigid insulation boards on top of the attic flooring joists and then install plywood over the top.

Why is insulation wrapped in plastic?

Encapsulated fiberglass batt insulation is a popular thermal and acoustical insulation solution for all types of construction and any climate zone across the U.S. It is easy to install and is wrapped in plastic to provide a comfortable, itch-free and dust-free installation.

Can you put a vapor barrier over insulation in attic?

In colder climates, where the home's heating system sees more use, the vapor barrier should typically be installed on the insulation's interior side. In warmer climates, where the home is often kept cooler, the vapor barrier should usually be installed on the exterior side.

What plastic to use to cover insulation?

The best insulation vapor barriers are made of polyethylene plastic and are reinforced to stand up against wear and tear. For extra protection, choose an insulation cover with mold and fire protection.

What happens if you install insulation without a mask?

If you do not like the sensation of dirt or dust on your skin, you will want to wear gloves and cover exposed skin. The dust of cellulose can still be hazardous for your eyes and lungs. If you are near cellulose being installed and do not wear a mask, you will inhale dust and irritate your lungs.

Can you over insulate a house?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

Should you cover insulation?

If the insulation is ever disturbed, it can cause many health problems that are otherwise easily avoided. Breathing in fiberglass particles can irritate your eyes, lungs, and skin. This health risk is probably the best reason you want to cover your fiberglass insulation.

When not to use vapor barrier?

Don't: Put Vapor Barriers on the Bottom of the Floor Joist in the Crawl Space. Because vapor barriers are good at retaining moisture, putting plastic sheeting on the joists can cause moisture to build up under the floor.

How well does plastic sheeting insulate?

The plastic film is too thin to block substantial heat transfer. While window insulation kits may help keep out some heat, the effect will likely be minimal. Thermal curtains or window shades, can offer more effective insulation and keep your home cooler during the summer.

How good of an insulator is plastic wrap?

No, plastic wrap does not have very many qualities that make it an excellent insulator. It may slightly assist in heat retention, but aluminum foil is a better insulator. Two layers of plastic wrap with air in between are the best way to use plastic wrap as an insulator if necessary.

Should you put plastic over insulation in a ceiling?

Exposed insulation is at risk of catching fire if not covered properly because it is extremely flammable. Installing a fire retardant plastic sheeting over insulation slows the fire damage rate in the case of an adverse event.

Should you pack insulation?

Benefits of Tightly Packed Insulation

Tightly packed insulation can reduce the chances of leaks and dead space. The process of installing the insulation using force makes it more likely that all cracks and holes are covered, even if they are not visible.

Can I cover attic insulation with plastic?

Even if the attic space is unheated, it's typically warmer than the outside air in winter. If you have chosen unfaced batting insulation for your rafters, you should staple sheets of plastic over the batting to accomplish a moisture barrier.

What can you cover insulation board with?

While there are no UV rays to destroy the foam board's insulative properties, interior exposure can create a fire hazard. Therefore, to qualify a building for an occupancy permit, most jurisdictions in North America demand that a thermal barrier, like drywall, cover the foam board.

Does attic insulation need to breathe?

In order for insulation to do its job, sufficient airflow to the outside surfaces is required. Good ventilation in your attic will allow the moisture to get out. An attic that is well ventilated will reduce the roof surface temperature and eliminate moisture.

Is it safe to leave insulation uncovered?

Health hazards of interacting with exposed insulation include: Risks of skin, eye and lung irritation. Potential for mold and mildew growth. Risk of increased health problems for kids, as uncovered insulation isn't child-proof.

Can I use Tyvek to cover insulation?

Don't worry about that one. But with that strong air stream, breaking up of fiberglass strands and moving them around is a cause for concern. So, buy Tyvek, and use it to cover the insulation; staple it to framework. It is not a vapor barrier, so it is OK to put over the insulation.

What can you put over insulation?

What can I use as a vapor barrier?
  1. Elastomeric coatings.
  2. Aluminum foil.
  3. Paper-backed aluminum.
  4. Polyethylene plastic sheet.
  5. Asphalt-coated Kraft paper.
  6. Metallized film.
  7. Vapor retarder paints.
  8. Extruded polystyrene or foil-faced foam board insulation.

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