How to Install Basement Carpet

Updated: Jul. 14, 2023

Keep your finished basement floor dry, even if the concrete gets wet.

how to carpet a basementFamily Handyman
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.

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Time
A full day
Complexity
Beginner
Cost
$101–250

Keeping a basement floor dry

Vapor barriers for basement floors

Use Option A to keep your floor dry if you have damp floors in your basement. Option B is sufficient if your floor is generally dry except for small amounts of moisture evaporating through the slab.

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. Here are a few tips to help you clean the concrete floor in your basement.

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.

Need help deciding the flooring for your basement? We have curated a list of why you should consider epoxy basement flooring.

Required Tools for this How to Carpet a Basement Floor Project

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

  • Circular saw
  • Cordless drill
  • Hammer

Required Materials for this How to Carpet a Basement Floor Project

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

  • 6-mil poly sheeting
  • Concrete screws
  • Plywood
  • Vapor barrier tape