Q: How should you detail the edge of a tile floor where it meets a carpet?

A: Tom Meehan, co-author of Working With Tile (Taunton Press, 2011) and a second-generation tile installer from Harwich, Mass., responds: When I have a choice, I always opt to install tile before carpeting, for a number of reasons. First, I can install the tile on a straight line that is easy to bring the carpet up to. And because setting tile can be a messy job with mortar, water, and grout, tiling first keeps the mess away from the carpet. It’s much easier to sweep carpet crumbs off tile than it is to clean mortar out of the pile of a carpet.

Tile before carpet.  First establish the  transition line between  the carpet and the tile  and draw a line.  Spread mortar for the  tile, pulling it away  from the line.
Roe Osborn Tile before carpet. First establish the transition line between the carpet and the tile and draw a line. Spread mortar for the tile, pulling it away from the line.
Then  install the tile using a  straightedge to keep  the edge of the tiles  in a perfectly straight line. Keep the edge  of the tile free of excess  mortar and grout.
Roe Osborn Then install the tile using a straightedge to keep the edge of the tiles in a perfectly straight line. Keep the edge of the tile free of excess mortar and grout.

Tiling Before Carpet

When the tile is to butt into carpet, I begin by drawing a straight line where I want the transition. I try to be mindful of exactly how and where the transition line between the carpet and the tile will be located. In the project shown in the photos below, the hallway carpet was to tuck under existing baseboard on either side of a tiled entry. So I drew the guideline for the tile at the edge of the wall rather than at the edge of baseboard, using a straightedge and a waterproof black marker to make the line.

When setting the tile, I comb the mortar straight back from the line, and then set the tiles with their outermost edges against a straightedge, in this case a 6-foot level. I make sure to scrape up any excess mortar or grout that oozes beyond the line. When the grout cures, the carpet layer can then position the tacking strip exactly where it needs to be to make an even transition between the two floors.

Tiling to Existing Carpet

If I need to tile up to carpet that has already been installed—at a doorway, for instance—I install the tile carefully to within about an inch of the carpet. Again, I’m careful not to get any mortar or grout on the carpet. To bridge the transition between the carpet and the tile, I fashion a T-shaped wooden strip that bridges the edge of the carpet and the edge of the tile (see illustration below). I make the strip from 1-by oak that I rip to 2 inches wide. I rabbet the edges about 3/8 inch deep on each side, leaving 1/4-inch-wide wings on the top. I round over the top edges and give the strip a couple of quick coats of poly.

To install the strip, I first remove the tackless strip, if it is in the way, and I fold the carpet flap from the threshold under itself, leaving a gap of about 1 1/2 inches between the tile and the carpet. Before folding the carpet, I apply a bead of construction adhesive to the under­side of the flap so that the carpet will adhere to itself. After making the fold, I sharpen the crease by going over it with a hammer. Then it’s just a matter of applying construction adhesive to the strip and pressing it into place, overlapping the edges of both the tile and the carpet. I usually put weight on the strip to hold it in place while the adhesive cures—overnight, if possible.

Tile-to-carpet transition. When tiling to an existing carpeted  floor, install the tile to within about an inch of the carpet. Fold the  flap of carpet under itself, using construction adhesive to keep  the flap from unfolding. Then install a wooden transition strip to  bridge between the two floors. Screws with plugged holes can be  used to secure the strip, but the author has had success using just  construction adhesive.
Tim Healey Tile-to-carpet transition. When tiling to an existing carpeted floor, install the tile to within about an inch of the carpet. Fold the flap of carpet under itself, using construction adhesive to keep the flap from unfolding. Then install a wooden transition strip to bridge between the two floors. Screws with plugged holes can be used to secure the strip, but the author has had success using just construction adhesive.