Tack strip is a thin wood strip with angled nails used to hold wall-to-wall carpet in place around a room’s edges. It’s nailed or glued to the subfloor. When carpet is removed, the strip leaves rows of small holes in concrete. Those holes can show through after the slab is ground or polished.
What Tack Strip Does
Wall-to-wall carpet doesn’t just lie on the floor. It’s stretched over the room and anchored at the edges by tack strip. The tiny angled pins on top grab the carpet backing like the hook side of Velcro and keep it from creeping.
On a concrete basement floor, the strip is usually fastened with short masonry nails or adhesive, running along every wall. Under the carpet you’ll also find a carpet pad, which is stapled or glued inside the strips.
Why Tack Strip Matters for a Concrete Floor Finish
When you tear out old carpet to finish the concrete underneath, the tack strip has to come up too. That’s when you see what it left behind:
- Rows of small nail holes a few inches from each wall
- Chips or spalls where nails pulled out a chunk of concrete
- Glue patches where strip was stuck down instead of nailed
On a thick, opaque coating, a crew fills those holes and they disappear. On a stain or polished finish, the patches can still show, because you’re looking at the concrete itself. Expect to see a faint line of dots near the walls unless the edges get covered by furniture or trim.
What to Do About Tack Strip Holes
Here’s the usual path from carpet to a finished slab:
- Pull the carpet, pad, and tack strip, and remove any nails left behind.
- Scrape off pad glue and staples.
- Grind the slab to clean it and open it up.
- Fill nail holes and chips with a patch, then coat, stain, or polish.
With a solid-color or flake coating, the patches are hidden. With stain or polish, patches will look a little different from the slab around them. Talk through that with your contractor before you pick a finish. Our guide to basement flooring alternatives to carpet and LVP compares options for this exact situation, and our concrete floor coatings guide covers finishes that hide repairs best.
Tack Strip FAQ
What is a tack strip used for?
Tack strip holds wall-to-wall carpet in place. It runs along the edges of the room, and its angled pins grip the carpet backing after the carpet is stretched over it.
Is tack strip necessary for carpet install?
For stretched wall-to-wall carpet, yes. Tack strip is what holds the tension at the edges. Carpet tile and glue-down carpet don’t use it.
Are tack strips still used?
Yes. Tack strip is still the standard way to install stretched wall-to-wall carpet, so you’ll find it under most carpeted basement floors.
What do you do with tack strip holes in concrete?
They get filled with a patch before the new finish goes down. Under an opaque coating the patches won’t show. Under stain or polish, they’ll usually stay faintly visible.