Should I Use Faced Insulation In My Basement?

You may have decided on batt insulation if you plan to insulate your basement. Since batt insulation has a low investment cost and DIY capabilities, it can seem like the obvious choice. Even so, you’re wondering what type to choose. Should you choose a faced batt or an unfaced batt? Does the choice matter depending on where in your basement you are insulating?

South Central Services has insulated hundreds of new and existing homes with spray foam. Around Greencastle, PA, batt insulation is more common in basements than spray foam. Batt insulation can be used in basements for the walls or the ceiling. Whether or not batt is the best choice and which type to use depends on where you are insulating.

By the end of this article, you will understand:

• What makes faced and unfaced insulation different
• Which insulations offer facings
• Where facings matter for basement insulation
• Whether faced insulation is best for your basement

What Makes Faced Insulation Different From Unfaced Insulation?

The critical difference between faced and unfaced insulation is vapor retardation. Fiberglass insulation has no natural defense against vapor transfer. It is easy for fiberglass to absorb moisture. Some fiberglass insulation comes with a vapor barrier facing to prevent vapor transfer and moisture absorption.

Generally, adding a facing will increase the cost of the insulation. However, unfaced insulation is usually less expensive than faced insulation by a marginal difference.

What Type Of Insulations Have Facings?

Fiberglass is the main insulation product that is sold with facings. You likely are thinking of fiberglass batts as the faced and unfaced products. However, fiberglass blankets or roll insulation can also be sold with facings.

Where Can Fiberglass Batts Be Installed In My Basement?

Fiberglass batts can technically be installed in the ceiling or walls. The nature of fiberglass batts requires it to be installed inside of cavities. So, fiberglass batts are only an option for finished basement walls.

When finishing a basement, a wood frame wall is constructed in front of the masonry walls. Fiberglass batts could be installed in this wood frame wall.

As for the ceiling, fiberglass batts can be stuffed inside the basement ceiling, finished or unfinished.

Where Can Fiberglass Blankets Be Installed In My Basement?

Fiberglass blankets are much larger than batts, meaning their only application in the basement is the basement walls.

However, fiberglass blankets can be fastened to a masonry wall. Unlike batt insulation, blankets can be used for finished or unfinished basements.

Do I Need Faced Fiberglass For My Basement Walls?

Basement walls have a higher vapor transmission probability than other building components. Both concrete and stone are porous materials with the ability to absorb moisture and release it again. Due to this greater likelihood of vapor transmission, facings are ideal when insulating basement walls. The vapor retarder facing should face the living space rather than the wall.

You could use either faced fiberglass batts or faced fiberglass blankets for this wall insulation. Between these two options, we will always recommend blankets over batts. Faced fiberglass blankets are larger than batts, meaning there are fewer seams and areas for vapor to infiltrate. While both types of fiberglass insulation have condensation risks, the risk is less significant with blanket insulation.

There are better options than faced fiberglass blankets for basement walls. Other insulations have better performance and also avoid condensation risks. However, blankets are the better choice between these two options.

Do I Need Faced Fiberglass For My Basement Ceiling?

Basement ceilings do not have direct contact with vapor, so vapor retardant facings are unnecessary. You can use unfaced fiberglass batts for your basement ceiling without condensation risks.

If you purchase faced fiberglass batts for your ceiling, you can still install them. The vapor retarder facing should face the basement living space.

Is Faced Insulation The Best Choice For My Basement?

If you’re using a fiberglass product in your basement, your walls should have a vapor retarder facing. However, fiberglass is not the best insulation available, especially for basement walls.

More costly insulations like closed cell spray foam offer more reliable performance. As a spray-applied insulation, spray foam can adhere in place without any gaps or sagging. Closed cell spray foam offers a seamless vapor barrier and eliminates condensation risk. Using spray foam requires hiring a professional contractor, but it has the fewest risks after installation.

Fiberglass is an insulation you can install yourself. However, it must fit into cavities exactly to offer its best performance. Installation errors are common and can lead to condensation problems and cold spots. Fiberglass also sags over time, so even an application with no gaps will have some insulation gaps after several years.

Another reason we recommend closed cell spray foam is your basement band boards. While fiberglass batt insulation can work well for basement ceilings and blanket insulation can be suitable for basement walls, fiberglass is not a solution for basement band boards. No matter how you insulate your walls or ceiling, your rim joists need an airtight seal. The transition from porous masonry walls to wood floor joists lets in cold air and vapor.

You may decide to hire a professional to insulate your basement rim joists. If so, having the professional handle all of your basement insulation would be worthwhile.

The best choice for your basement is closed cell spray foam. If you are determined to use a fiberglass product in your basement, your best option is faced blanket insulation for the walls or unfaced batt insulation for the ceiling. No matter what, consider pairing your fiberglass with an airtight seal in the basement band boards.

The Bottom Line About Vapor Retarder Facings In Your Basement

Basements are below-grade spaces, meaning they often have excess vapor and moisture. Basement walls are an area that needs some vapor barrier or retarder. In the case of faced insulation, you should opt for vapor retarder facings for your basement wall insulation.

Your basement ceiling is the transition between the below-grade basement and the rest of your home above the ground. 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.

Vapor retarder facings are not the only way to get a vapor barrier in your basement walls. We recommend closed cell spray foam insulation if you want to avoid condensation risks altogether.

Now that you know whether or not you should use faced insulation in your basement, your next step is to:

• Discover the best way to insulate your basement walls
• Compare the best insulations for basement ceilings
• Investigate the benefits of insulation in your rim joists