How To Tell if Your Crawlspace Foundation Is Insulated

How To Tell if Your Crawlspace Foundation Is Insulated

crawlspace foundationDo your feet get cold walking around the house in the middle of winter even when the heat is on full blast? If so, it sounds like you may need to insulate your crawlspace foundation. A crawlspace is a type of foundation where the house sits elevated, usually between 18-24 inches, above the ground. Without insulation, crawlspace foundations can lead to heating and cooling losses through the floors of your home and also poor air quality within the home.

To determine whether insulation (or lack thereof) could be to blame, take a peek underneath your home. Do you see damp or loosely hanging insulation? This means that the crawlspace insulation is either outdated or wasn’t installed properly in the first place. Other homeowners with older homes may find that no installation was ever installed into the crawlspace. This is especially common with homes built prior to 1990 when energy-conserving building codes were put in place.

Once you’ve figured out that crawlspace foundation insulation is needed, it’s time to install it.  This task can easily be done without the help of a professional by using these helpful tips:

Ventilated or not ventilated?

First, it’s important to determine whether you have a ventilated crawlspace foundation or not. The type that your home has will affect what insulation you should use, so this should be determined before going to the hardware store.


Many crawlspaces were designed with ventilation in order to prevent the buildup of moisture and, therefore, mold and mildew growth. This type of crawlspace foundation should be insulated with fiberglass, which can be easily installed. Insulation should be placed between the floor joists underneath the subfloor. Be sure to also insulate plumbing and ducts to ensure your home stays as energy efficient as possible. Once insulation is down, cover it with a vapor barrier so mold and mildew don’t contaminate the crawlspace. Vapor barriers are available at hardware stores and can be easily taped to the insulation to secure in place.

crawlspace foundation

Not Ventilated

For crawlspace foundations that are not ventilated, it’s best to insulate the walls of the area completely. When calculating how much insulation you’ll need, measure from the top of the band joist down the wall and then two feet along the ground. Multiply this number by the measurement of the wall perimeter. This will tell you how many square feet of insulation material you’ll need. One benefit of insulating the entire wall is that pipes and ductwork will not require their own insulation to improve energy efficiency or to prevent freezing since they will lie within the insulated crawlspace foundation area.

Why should you go bother insulating a crawlspace foundation? Preventing heating and cooling losses through the floors of your home will not only keep you at a comfortable temperature, but will also have an impact on your monthly bill. It is estimated that your heating and cooling system makes up between 50-75% of your monthly energy bills, so cutting back on these losses will put money back in your pocket!