Is it possible to insulate the joists in a 14×40 area with a 40-inch high crawl space to help with cold floors in winter?
Asked by Uroš Lončarević 
2 months ago
Last Updated: September 9, 2024
I have this extra space with a 40″ high crawl space that’s about 14’x40′. The floors get really cold in the winter. Do you think it would help if I insulated the joists?
Absolutely, the code for floor insulation in my area is R19.
Absolutely
Make sure to air seal the crawlspace and keep it conditioned. When we did that for our addition, we never had cold floors. I personally think air sealing is a bit easier than insulating all the floor joists, but both methods work well.
That condition applies only if the perimeter is properly sealed and insulated. Otherwise, you’ll be heating the great outdoors.
That’s exactly what I was trying to say about air sealing the crawl space. Make sure to seal the perimeter completely. No need to worry about the insulation batts falling out of the joists or getting wet over time.
When helping DIYers who may be starting from scratch, recommends being very specific, especially with topics they may not fully grasp.
Definitely. It’s important to be proactive in controlling mice.
Have you thought about ventilating the crawl space? Consider adding operable vents for the winter. Also, don’t forget to insulate the floor. Is the crawl space floor made of dirt? Is it moist? By the way, the vapor retarder should be placed UP in the crawl space (if there’s one already). Where are you located?