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How to Carpet a Basement Floor

Prevent damp basement floors from ruining carpet and other finished flooring. Install dimpled polyethylene to create an air space between the concrete and the finished floor, sealing off dampness and giving moisture a chance to dissipate.

By the DIY experts of The Family Handyman Magazine

  • COST
  • CostCostCost $100 - $500
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    Polyethylene sheets are more expensive than 6 mil poly vapor barrier, but are much more effective if you have a moisture problem.

Keeping a basement floor dry

For a dry, mold-free finished basement floor, always install a vapor barrier before laying a wood subfloor or carpet pad.

Any kind of persistent moisture will allow mold to get a foothold and soon ruin carpet or wood flooring. For below-grade slabs, assume that the concrete floor will get damp at some point. You then have two options, depending on your circumstances. And both of the options use the same layers of 1/2-in. plywood, carpet pad and carpet as shown. It's the initial layer that differs.

Option B (in the photo) will work on a concrete floor that has no persistent dampness, seepage or leakage. The 6-mil layer of plastic helps to minimize potential moisture migration up into the plywood. Option A can be applied on concrete where there's a higher risk of some dampness. The initial layer is a durable high-density polyethylene sheet or similar system that uses evenly spaced 3/8-in. tall dimples to create air space and a moisture barrier between the concrete and the plywood.

Lay the sheet over the concrete floor (dimples down), overlap adjacent edges and tape the seams. Add the plywood layer on top and anchor it to the concrete with 15 concrete screws (predrilled and countersunk) per 4 x 8-ft. sheet.

Dimpled polyethylene underlayment is available from home centers, flooring suppliers or online.

Before you proceed, consult a local building inspector to determine specific building codes for this type of project. Also, be sure your basement floor is level. Finally, note that these options will raise your floor by 1-1/4 to 1-1/2 in., so make sure this added height won't create problems.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

    • Hammer
    • Cordless drill
    • Circular saw

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

    • 6 mil poly or High density, dimpled polyethylene sheet
    • Vapor barrier tape
    • Concrete screws
    • Plywood

Comments from DIY Community Members

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1 - 8 of 8 comments
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August 21, 11:42 AM [GMT -5]

You can get this product at Lowe's. They can special order if it's not in stock. I would still recommend etching and sealing your floor prior to applying the dimpled membrane. Yes' it will allow for air circulation but if you have an issue with hydro-static pressure you will still get some moisture and possibly mold.

January 16, 4:14 PM [GMT -5]

We have a tiled basement floor, I would like to install carpet on top of it. We don't have any water issues in the basement but about a year ago we got molding in one particular portion of the basement and it used to smell moldy too. This was just one time occurrence, it has not spread and it did not happen to any other area. What are the suggestions for installing the carpet??

July 20, 8:56 AM [GMT -5]

How much money will we cost?

July 01, 2:58 PM [GMT -5]

Where do I find this product with the nubs, hd didn't have it.

May 08, 10:17 PM [GMT -5]

it was very easy to do, and our basement has stayed dry!

October 11, 10:07 PM [GMT -5]

I thought about doing this project but having an older home I don't have a level floor. There is not huge dips but I didn't want to start the project with this consideration.

August 17, 12:39 PM [GMT -5]

I'm in the process of doing this project and looking for input. What do you do around the floor drain?

June 25, 2:37 AM [GMT -5]

I am using carpet for several years and help makes my home become more elegant than before.

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How to Carpet a Basement Floor

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