When not to use faced insulation?

Author: Prof. Cora Grimes  |  Last update: Monday, January 26, 2026

Unfaced insulation is great for new construction, remodels, walls, floors, ceilings, basements, attics and crawlspaces. It's best used for interior wall applications that do not face the outside and also in rooms that don't need moisture control, like living rooms, dining rooms and studies.

Is it bad to use faced insulation in interior walls?

Faced insulation is completely obsolete. Do not use it. Don't even worry about vapor barrier on the inside if you are painting the wall. Paint is an acceptable vapor barrier, and keeps the moisture from ever getting in the wall, instead of trapping it between a poly barrier and the back of the drywall.

Does it matter if insulation is faced or unfaced?

Unlike faced insulation, unfaced insulation is non-combustible since it does not contain any combustible materials such as paper or plastic. Also, as mentioned above, unfaced insulation is much cheaper than its faced counterpart. Additionally, unfaced insulation is a great way to soundproof your interior walls.

When to use paper faced insulation?

Kraft-faced insulation includes a paper vapor retarder, which helps prevent mold and mildew. Kraft-faced insulation should be installed in exterior walls, exterior basement walls, and attic ceilings by pressing the product into the wall cavity with the paper side facing outward, towards the installer.

Where should you not put insulation?

Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.

You Won't Believe This Insulation Solution for COLD Walls!

Does attic insulation need to be faced?

You can use faced or unfaced batting when installing between the roof rafters of finished attic spaces. When using paper or plastic batting insulation, that moisture barrier should face outward toward the attic space. Even if the attic space is unheated, it's typically warmer than the outside air in winter.

What ruins insulation?

Moisture damage

This can occur due to leaks in the roof or foundation, inadequate ventilation, or high humidity levels inside a building. Moisture can cause the insulation material to become compressed and lose its effectiveness, leading to increased energy consumption and potential mold growth.

Where do you need faced insulation?

Faced Insulation

This is especially important for areas that are prone to condensation or moisture accumulation, such as attics or walls near bathrooms or kitchens. The vapor retarder helps keep moisture from becoming trapped in the walls and ceiling, ensuring that your home stays dry and comfortable.

What is R13 faced insulation used for?

R13 batt insulation is typically used to attenuate sound in interior wall cavities. It is akin to a large blanket, designed specifically to fill a wall, floor, or ceiling cavity.

Which insulation is best for an attic?

Fiberglass batt is considered to be the best insulation for attics. Compared to other insulation materials, it is the cheapest and easiest to install.

What happens if you install faced insulation backwards?

If installed incorrectly, moisture can become trapped between the facing and cause mold, rotting, and reduced R-value.

What is the difference between R13 and R19 insulation?

R13 insulation is generally more affordable, which makes it an attractive option for budget-conscious projects. However, R19 insulation offers better long-term advantages because of its higher R-value.

Is it OK to leave faced insulation uncovered?

Faced insulation

Kraft and standard foil facings can burn and must not be left exposed. If an exposed application is required, use FSK-25 flame-resistant faced insulation.

Should you put plastic over insulation before drywall?

Should I Put Vapor Barrier Plastic Over Insulation Before Drywall? 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.

What insulation is best for interior walls?

Batt insulation is a type of insulation blanket. These are pre-cut sections of insulation that are usually fiberglass, although cellulose, mineral wool, natural fibers and plastic versions are also available. This type of insulation is the best insulation for unfinished walls, floors and ceilings.

Is it okay to use faced insulation on interior walls?

For example, faced insulation is better used on exterior walls, attic ceilings, basements, and bathrooms, while unfaced one is commonly used on interior walls, crawl spaces, or between floors.

Is R13 OK for walls?

For walls, r13 insulation is a good choice in most instances, and because your basement is below the ground, there's some natural protection from the earth around it.

Is faced insulation better than unfaced?

Unfaced insulation is non-combustible.

However, it's common for a layer of faced insulation to be used in the exterior walls and attic ceilings to prevent water from entering the home, while unfaced insulation can be added to improve the heat retention ability and reduce the risk of fire.

Should faced insulation be stapled?

If you're using faced insulation, install it with the vapor retarder positioned down toward the room. Hold the insulation up with one hand, while stapling the flange on both sides every 6" - 8" with the other hand. Leave a little extra on each end to cover the top plate of the outside wall.

Do you use faced insulation for ceiling?

Ceiling insulation does not need to be faced because it does not experience moisture like the rest of the basement. If you have already purchased faced batt insulation, you can install it in your basement ceiling. However, you don't need to purchase faced insulation for your basement ceiling intentionally.

Can mold grow on fiberglass insulation?

Because of the high amount of air that can move through fiberglass however, trapped particles can be filtered out of the air including food sources for mold and mold spores themselves. Over time, given the right conditions, mold can grow in fiberglass.

What is the best insulation for exterior walls?

Foam Board or Rigid Foam

Foam boards -- rigid panels of insulation -- can be used to insulate almost any part of your home, from the roof down to the foundation. They are very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches.

Should I insulate my attic floor or ceiling?

Insulating your attic floor can create a vented attic, which is ideal for storage and not needing temperature control upstairs. Insulating the ceiling will make an unvented attic, which allows you to control the temperature for temperamental storage items, living space, and HVAC ductwork.

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