Think Your Home is Insulated? Check the Crawl Space

Insulating the floor over a crawl space can reduce heating costs, particularly in colder climates, but it doesn’t provide as big a return on investment as insulating an attic or sealing cracks and gaps around your home.

But if insulating your floor is something you’re interested in, here are some things to keep in mind:

Crawl space with upper floor insulation between wooden joists/beams
Having the paper facing turned toward the heated living space helps prevent condensation from forming and keeps your insulation in top shape. (Jason Finn via

First, be sure to turn the paper facing on the insulation up toward the heated living space.

The paper facing acts as a vapor retarder, preventing moisture from passing through the insulation and potentially causing damage to the building structure or reducing the insulation’s effectiveness. Additionally, it usually has a flame-retardant coating that helps to improve the fire resistance of the insulation when facing the heated area.

Secondly, use insulation support wires to hold the insulation in place. You don’t want it to sag or shift over time.

Roll of plastic vapor barrier and staple gun and staple on an OSB board
A plastic vapor barrier prevents moisture from causing damage to the structural components and insulation of the building above a home’s crawl space. (MyrKu via

And finally, cover the ground in your crawl space with 6-mil-thick plastic. This will help reduce moisture problems under your home, and keep your floors and insulation dry and free from damage.

So, there you have it! Some quick tips on insulating the floor over a crawl space. I hope this helps you stay warm and cozy this winter season.

Watch this video to find out more.

Further Information

Danny Lipford: Frank asks, “Do I really need to insulate my crawl space?”

While insulating your crawl space is not absolutely necessary, it will help a lot to minimize any of the moisture or temperature intrusions into your home. But to tell you the truth, it’ll take you a long time to get your money back on the money that you spend on insulating that crawl space.

Far better to spend that money in the attic making sure it’s insulated well, and sealing up the envelope of your home. But if you decide to put insulation in your crawl space, make sure you turn the paper toward the living space, so that you don’t create any type of moisture trap.

Now, moisture is a big problem in crawl spaces, so it is strongly recommended to put a moisture barrier right on the ground. You can use a 6-mil plastic, clear or black, then you can weight down the perimeter of it with some small bricks, gravel, sand, or just a little bit of dirt to keep it from blowing away.

This will prevent the ground moisture from migrating up into your home, which ends up costing you some money.


  1. We purchased a manufactured home 14 months ago. Last year the toilet in the master bathroom stopped filling. Maintenance came and supposedly fixed the problem, but this year with sub zero temperature it has happened again. When the weather warms up the water flows again.. we put a heater in the bathroom today and the toilet is working again.
    Thru all this all the other fixtures, washing machine and toilet have worked with out ant problems. Any ideas, ANY help would be appreciated

  2. After insulating my crawlspace which is exposed to the outside, should I place sheathing on the joist to encapsulate it or just leave it just with the insulation open.

    • Hi, Juan,
      Danny says, “I would leave it with the insulation open or you can install house wrap and staple it to the floor joist. Good luck with this project!”

  3. We had a sunroom added many years ago and the contractor put insulation under the deck. Now some of the insulation is falling or looks like some animal has gotten into it and tearing it apart in places. Would it be best to cover it, or leave it, any suggestions?


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