Why and How to Insulate a Crawl Space

Last updated: January 21, 2022


If your home has a crawl space foundation, there are a few simple signs of poor crawl space insulation. Even floor areas above the crawl space may become uncomfortable and cold to walk on barefoot through cold winter months. In this post, I will explain why and how to insulate a crawl space.

Why Insulate a Crawling Space?

 The crawl space presents more opportunities for moisture vapor to mix with the air in the home, which can lead to basement mold growth. If the moisture continues to build up, you may begin to notice water leaking from walls or from one floor to another. Know some more reasons that force homeowners to seek a solution against excess moisture in this area.

Leaking Walls and Mold Growth 

Although it’s not unusual to have leaking walls, if the walls have frost-proofing, the frost usually isn’t the culprit. Instead, it’s the soil beneath the earth that’s commonly the culprit. Improper excavation around a house can allow foundation problems to develop. For example, if dirt weren’t sealed off from the outside and allowed to subside, it would eventually break down and get filled with water. The result would be excess moisture in the basement that would lead to basement mold or air leaks.

Allergy and Respiratory Infections 

Basement mold can cause an array of respiratory illnesses, plus it can also lead to severe allergic reactions. Allergic reactions happen when people in the home breathe in microscopic mold spores. Mold has also been linked to the development of cancer in some individuals. 

Although all mold is not harmful, the spores from indoor air can create a reaction that can cause a person to become ill. Even though most people are not allergic to mold, they can still develop an illness due to breathing in the mold.

How to Insulate a Crawl Space?

There are three main types of crawl space insulation that can help prevent this problem from developing.

Plastic Membrane Installation 

The first is to seal off the perimeter of the crawl space insulation board. You can accomplish this with a plastic membrane. This membrane will serve as a vapor barrier that won’t allow moisture to penetrate the board’s surface. The vapor barrier will keep air from penetrating the surface, which will prevent the growth of mold. It is important to note that the energy efficiency of this method will decrease as the temperature inside rises.

Impermeable Sheet 

Another type of crawl space insulation is an impermeable sheet. These sheets are placed directly over the top of the crawl space vents. These vented compartments allow air to pass through, and the sheet will stop air leaks. However, the sheet will need to be cut to fit the area of the vents and may need to have additional sealing material added to keep air out.

Fiberglass System 

One more type of crawl space insulation that is used is a fiberglass batt system. Fiberglass batt systems are similar to sheet materials; however, they are completely sealed in place. The insulation is then installed on top of the fiberglass. Once installed properly, it should be slightly higher than the actual ceiling to prevent moisture from penetrating the surface. Always hire an expert for crawl space repair in Sioux Falls.

Show More
Back to top button