What kind of insulation should you use in your crawl space? That depends on whether you are venting or closing the crawl space. Open or ventilated crawl spaces can be insulated differently than closed or encapsulated crawl spaces. Decide first which crawl space you will have before deciding the best crawl space insulation materials to use.
Best Vented Crawl Space Insulation Materials
When your crawl space is open or vented, it allows outside temperatures to freely enter. Even vents that open and close automatically can allow extreme temperatures into your crawl space. Because of this, floor insulation is recommended for open crawl spaces.
Types of Crawl Space Floor Insulation
Many contractors will install batt insulation like fiberglass or rock wool. We see fiberglass sub-floor insulation the most in our area. Some contractors will also spray foam the sub-floor. Since we encourage crawl space encapsulation over vented crawl spaces, we remove a lot of sub-floor insulation.
CAUTION! Spray foam insulation is almost impossible to remove. It can also trap moisture and mold. Many contractors will install spray foam insulation to cover wet moldy wood.
Best Encapsulated Crawl Space Insulation Materials
Crawl space encapsulation requires a different insulation approach. You can insulate the sub-floor of an encapsulated crawl space. Foamboard or insulation vapor barrier is the preferred choice of Crawl Space Ninja. Not just any foamboard will do and sub-floor insulation can still trap mold and moisture.
Foundation wall insulation for the crawl space should be rated to touch the ground. This is why we choose EPS foamboard. It is a termite-resistant expanded polystyrene (EPS) insulation for all types of construction applications. InsulBarrier is another great product for foundation wall insulation in both crawl spaces and basements.
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10 thoughts on “What Kind of Insulation Should I Use in My Crawl Space?”
WANT ESTIMATE FOR SPRING INSTALL PLUS ALL COST.
Please call customer service to setup on-site appointment if you are in our service area at 865-659-0390 or fill out this form and someone will call you. https://crawlspaceninja.com/free-assessment/ We can only do on-site estimates after meeting with you and viewing the property. Thank you.
Looking for some one to insulate crawl space.
Hi Barbara, I am not sure where you are located. Here is our service area. Thanks and hope that helps. https://crawlspaceninja.com/service-area/
Doing research to do my crawl space that is directly open to conditioned and finished basement. I am reading that international code requires a thermal barrier such as drywall, wood, cement board to cover foam board on walls. How do you get around this requirement? Does the foam board you use have an UL fire rating that meets the code? Thank you
Yes, ours has the UL fire rating and is event stamped on the board.
Choosing the right insulation for your crawl space depends on whether it’s vented or closed. Here’s what you need to know:
Vented Crawl Spaces: These allow outside temperatures to enter. For open crawl spaces, floor insulation is recommended to combat temperature fluctuations.
Closed Crawl Spaces: Encapsulated crawl spaces require insulation on walls and floors to maintain a stable environment.
Decide the type of crawl space first, then choose appropriate materials like spray foam or rigid foam for optimal insulation.
Thank you for sharing.
My original house has a half basement, half crawl space. A small addition was put on sometime in the 1980s, which extends from the crawl space into a VERY shallow crawl space that I can’t access myself. The small addition has vents and from I can tell with a flashlight has some bat insulation in the floor joists. The original crawl space has bat insulation in the subfloor and nothing else. I am planning to finish off the “full basement” portion of my basement, but am unsure if I should seal off the crawl space and insulated the crawl space walls, keep air flowing between the full basement and original crawl space and insulate either the crawl space walls and/or floor joists, or something else? Also, the addition with the shallow crawl space can be seen from the original crawl space between the floor joists. Do I seal off access to this crawl space? Hope this is not too confusing. For some background, I live in southeastern PA, am pretty handy, and enjoy tackling various DIY projects. Thanks in advance!
Hi Chris, my apologies but there is a lot to tackle here. Too much to answer in a chat. I recommend you do a paid 30-minute consultation to go over everything and develop a plan. Here is the link to learn more: https://buymeacoffee.com/csninja/e/111638