Can You Install Carpet Over Carpet?

Installing carpet over carpet can be tempting in some situations. Skipping removal saves on the cost and labor of tearing up and disposing of the old carpet. Plus, glued-down carpeting is extra difficult to rip off of the subfloor.

Despite these temptations, do not install carpet over carpet. Doing so traps dust and mold between the layers of carpet. Not only that but carpeting is a poor base for another layer of carpeting. Tack strips cannot be nailed down to carpeting. Finally, creating thicker layers of flooring throws off other room elements: doors, casing, baseboards, and ceiling height.

Traps Dust and Mold

Old carpeting harbors dust and mold. Studies show that mold and mildew in carpeting are exacerbated by the presence of dust.

Dust and moisture, with high temperatures added, equals mold and mildew. It is virtually impossible to clean an old carpet enough to remove all of the dust. But if you choose to have the old carpet professionally cleaned first, you're already spending money that could have been spent on removing the carpet.

Poor Base For Carpet

Carpeting needs a solid base for proper installation and performance. A carpet installed with an improper base will wear out quickly.

Traffic patterns already worn into the existing carpet will quickly be telegraphed up to the new carpet.

Tack Strips Cannot be Attached

Carpeting requires spiked tack strips around the perimeter to stretch it out and hold it in place. If you leave the carpet in place, you cannot nail down the tack strips.

The anchoring nails on tack strips are only about 3/4 inch long— far too short to penetrate the old carpet and pad and reach into the subfloor.

Raised Floor Creates Problems

Dual carpet layers create a higher floor.

By adding an extra layer to your flooring, you are effectively lowering your ceiling. In a basement or any other height-challenged room, every inch counts.

Adding height to the carpet means that doors will scrape and thus will need to be cut off at the bottom. Also, wood trim, casing, and baseboards will have to be removed and reinstalled.

How to Recycle Old Carpet

If you are concerned about dumping carpet in landfills, there is a non-profit consortium called Carpet America Recovery Effort that helps connect homeowners to companies that recycle carpeting.

If your reason for leaving the old carpet in place is an environmental concern, a variety of re-use stores may gladly accept carpeting in relatively good shape. Even a very old carpet may have good sections that can be cut out to serve small rooms or to make area rugs.

Tips for Installing Carpet Over Carpet

Despite the disadvantages, do you still want to install carpet over carpet? Here are a few tips if you decide to go that route:

• Choose a low pile. The best choice for a carpet-over-carpet installation is a bottom (base) carpet with an extremely low pile. The lower the pile, the better, since will minimize the degree to which the floor will be raised.
• Have the carpet professionally cleaned: Before installing the top layer of carpet, thoroughly clean the bottom layer.
• Apply a thin underlayment. Laying down a thin plywood underlayment atop the old low-pile carpet is better than just putting the new carpet straight onto the existing carpeting. The underlayment will provide a rigid base for the new carpet and a place to attach tack strips. Make sure to securely nail the underlayment down to the subfloor through the old carpeting.