How To Insulate A Floor | Do It Yourself

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How To Insulate A Floor In A Vented Crawl Space

Gary S. from Billings, MT wrote:

Hey Itchy, stop scratching for a minute and tell me how to insulate a vented crawl space.

Oh boy, you're gonna have a good time with this one! We'll see who's doing the scratching when you get finished. When insulating a crawl space you'll find they are usually filled with all sorts of surprises like spiders, critters and who knows what. Just follow the instructions below and by the end of the day your crawl space will be insulated. Enjoy!

Before you get started you need to get all dressed up in your coveralls, dust mask and don't forget your goggles. Unless you ate a lot of carrots and can see in the dark you better bring along a drop light.

The first thing you'll need to do is to cover the ground with sheets of visqueen. I would recommend a thickness of about six-mil. Make sure the pieces of visqueen overlap by about a foot or so and it should also extend a few inches up the foundation walls. Once you're done with the ground cover you will now have a cleaner crawl space and you'll be ready to install the floor insulation.

Start installing the kraft paper fiberglass batts between the floor joists. Make sure the paper is against the floor as it acts as a vapor barrier. Staple the batt into place using the tabs on the sides, and fill any gaps with scrap pieces of insulation. Continue with this process, paying close attention to ducts and pipes that will require cutting the insulation to fit. Try not to compress it too much as I've heard it looses it's r-value. Are we having fun yet! Boy howdy, there's more to come.

Okay, you have the crawl space insulated but now you need to make sure the insulation stays in place. The easiest way by far is to use wire fasteners, sometimes called "lightning rods" to secure the insulation and keep it from falling. These bend easily and fit between the floor joists. Make sure to install them against the insulation every couple of feet and about 4 inches from the end of each batt. If you don't want to use the wire fasteners you could also staple twine in a shoelace pattern to the joists to secure the insulation.

While you're picking up loose paper and pieces of fiberglass take a look at your insulated floor in the crawl space and fill any gaps with the loose insulation. Make sure your ground cover hasn't shifted. If it all looks good grab your stuff and climb out of there and give yourself a pat on the back. Don't forget to insulate the crawl space cover by stapling a batt to it. Put it back in place and you're done!

Next, give yourself a good scratching. You've now accomplished one of the most disgusting, nasty jobs in the world of insulation - insulating a floor in the crawl space. Make sure you don't scare your wife with that outfit your wearing, take it off and go jump in the shower because you deserve it.

Related Tips and Advice:

How To Insulate Your Attic With Fiberglass Batts or Blankets
How To Install Blown In Insulation In Your Attic
How To Insulate A Concrete Wall
How To Insulate Ducts

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