Best Way To Insulate Your Basement Walls

You know that your basement needs insulation. You’ve decided to insulate the walls rather than the ceiling. But you want to make sure that you insulate the walls effectively. What insulation products can you use? What are your options, and what benefits do they offer?

South Central Services has insulated hundreds of new and existing homes with spray foam. Depending on your budget and insulation goals, there are many different ways to insulate basement walls. This article will break down the three insulation options for your basement walls.

By the end of this article, you will know:

• The most common solution for basement wall insulation
• A better solution for basement wall insulation
• The best solution for basement wall insulation

The Most Common Solution: Fiberglass Batt Insulation

Fiberglass batts are one of the most frequently used insulation products on the market. Fiberglass batt insulation is popular because it is relatively inexpensive and can be installed DIY. Batt insulation is ideal for homeowners who are sensitive to price or prefer to do work themselves.

When it comes to basement walls, fiberglass batts are installed in a wood-frame wall. Finishing your basement requires a wood-frame wall to fasten your drywall. To insulate your basement walls with fiberglass batts, a wood-frame wall must be constructed in front of the masonry basement walls. An inch gap is commonly between the wood-frame and the masonry wall.

While this can be completed as a relatively inexpensive DIY, installing fiberglass batts in the basement comes with some risk. Batt insulation cannot create an airtight seal; it functions by letting air pass through it to slow heat transfer. Additionally, fiberglass batts are notorious for having gaps and sagging over time.

The actual properties of fiberglass increase the risk of condensation. Condensation can form when air travels between the finished basement space and the porous masonry wall. Fiberglass batts make it easy for air to infiltrate.

While fiberglass batt insulation is popular for finished basements, we do not recommend this solution. If you opt for batt insulation, ensure the batts completely fill the wood-frame cavities with no gaps. Limit as much air transfer as you can to mitigate condensation risk.

A Better Solution: Faced Fiberglass Blankets

If you are determined to insulate your basement yourself, there is a better solution than fiberglass batts: faced fiberglass blankets. The product is still fiberglass, so you can still save some money compared to alternative basement insulations. Even better, you can use this insulation method for both finished and unfinished basements.

Unlike fiberglass batts, you can install faced fiberglass blankets directly against the masonry wall. These insulation blankets can be fastened to the basement wall, providing some insulation to an unfinished basement.

If you want to finish your basement, you can construct a wood-frame wall in front of the insulation blanket. For a fiberglass batt solution, an inch gap would be between the wood-frame wall and the masonry wall. With faced fiberglass blankets, the gap between the walls is filled with the blanket of insulation.

While this form of fiberglass still cannot stop air infiltration, there are fewer gaps and seams because the blanket is much larger than batt insulation.

Additionally, a fiberglass blanket cuts down on some of the condensation risks. If air gets between the masonry wall and the fiberglass, there can still be problems. However, there is less potential for condensation than with batt insulation.

Homeowners who want fiberglass insulation in their basement should choose faced fiberglass blankets. This insulation cannot wholly mitigate condensation risks, but blanket insulation offers fewer condensation risks than batt. Additionally, you can utilize this solution for finished or unfinished basements.

The Best Solution: Closed Cell Spray Foam

If you can afford spray foam, the best option for basement wall insulation is closed cell spray foam. Unlike fiberglass insulation, spray foam can create an airtight seal. Spray foam also has a seamless application, so there are no possibilities of gaps or cracks in the insulation.

You should not install closed cell spray foam yourself. While there are DIY spray foam kits for sale, these kits will not save you money and cannot deliver a reliably safe foam product.

If you want spray foam for your basement, you must find and hire a qualified spray foam contractor.

The cost and installation barriers can dissuade homeowners from choosing spray foam. However, closed cell spray foam does offer the best performance for your basement walls. Closed cell can also be used for a finished or an unfinished basement.

Closed cell spray foam insulation can be installed on the wood-frame wall for a finished basement, or against the masonry wall for an unfinished basement. No matter where it is installed, closed cell can create a seamless vapor barrier and stop air infiltration.

Because air cannot exchange between the basement space and the masonry wall, there is no risk of condensation.

We recommend closed cell spray foam for basement walls. Its airtight seal eliminates the risk of condensation. Spray foam is a high-performing insulation that creates an effective and seamless thermal barrier.

What Happens If My Basement Walls Have Condensation?

You may be wondering what the concern is about condensation on your masonry basement walls. Why should you be concerned about condensation in your basement?

Condensation is unmanaged moisture. Left unchecked, condensation can lead to mold, mildew, and wood rot. If you construct a wood frame to hold fiberglass insulation, any condensation can lead to these serious problems behind the basement drywall.

The Bottom Line About How Basement Walls Should Be Insulated

Basements must be insulated to meet building codes. Depending on whether or not you want a finished basement, there are several options for basement wall insulation. Fiberglass insulation of some kind is generally standard in new home construction. However, this type of insulation creates condensation risks due to air infiltration.

To avoid the risk of condensation, the best option for basement wall insulation is closed cell spray foam. Spray foam offers better performance than fiberglass and also creates an airtight seal. However, spray foam is also more expensive and requires hiring a professional.

If you can’t choose spray foam insulation, we recommend fiberglass blankets. With fewer gaps and seams, blanket insulation delivers better performance and lower condensation risk than batt.

Now that you know the options for insulating your basement walls, your next step is to:

• Estimate the cost of insulating your basement walls with spray foam
• Compare fiberglass batt insulation with spray foam insulation
• Discover why homeowners trust South Central Services with their basement insulation