Tile Installation Tips From a Tile Expert

Diagonal layout

The usual way to lay tile diagonally is to mark 45-degree diagonal lines on the wall or floor. But when that angle isn’t 45 degrees, as with the diamond-shaped tile you see here, getting exact lines is even harder. So we’ll show you a better way: Mark a single layout line and center the tiles over it by aligning the corners of the tile with the line. Build a pyramid centered on the line and use the sides of the pyramid to align each diagonal course. Check the sides of the pyramid occasionally with a straightedge.

Specialty thin-set mortar

Thin-set mortar is the best bedding adhesive for most tile. But if you’re setting tiles larger than 12 x 12 in., look for terms like “medium bed,” “large tile” or “large format” on the bag label. Bigger tile requires a thicker bed, and unlike standard thin-set, medium-bed mortar doesn’t lose its bonding strength when you lay it on thick. It’s also firmer and shrinks less, so tiles stay in position better while the mortar hardens. Medium-bed mortar is available at tile stores and some home centers.

Layout tip

If you’re planning a wall niche, lay out the tile and take some measurements to determine the size of the niche. If you custom-size the niche to fit between full tiles, you’ll get a better-looking installation and avoid some cutting. With a diagonal tile layout like the one shown here, you’ll get full tiles and half tiles. If trim will frame the niche, be sure to factor it into the layout.

Clean-up aid

When you’re shopping for tile supplies, take a detour to the sandpaper aisle and pick up a pack of fine abrasive pads. Along with a little water, they’re great for removing stubborn thin-set smudges on the face of tile. And they won’t scratch the glossy glaze.

Coverage guidelines

Your thin-set probably has a chart like this on the label. Don't rely on it. The recommendations are a good starting point, but they don't guarantee a thin-set bed thick enough to provide full contact with the tile. And without full contact, you don't get full support or adhesion.

As the chart shows, larger tiles require larger trowel notches (to provide a thicker bed). But other factors matter too: the flatness of the wall or floor, or the texture of the tile's back. So the only reliable way to know that the bed is thick enough is to set the first few tiles, then immediately pry them up. If the tile hasn't made full contact, you'll see it. The easiest solution is to use the next notch size. With tiles larger than 12 in., it's a good idea to also “back butter” them with thin-set. Also keep an eye on “squeeze-out” during the job. If you don't see thin-set squeezing out between tiles, pull up a tile to check coverage.

Quick pick up

A suction cup lets you lift a sunken tile or adjust a crooked one. Some home centers and hardware stores carry them; most don’t. To shop online, search for “suction cup handle.” Keep in mind that they only work on smooth-faced tile.

Budget tile saw

Huge tiles are popular these days, and the best way to cut them is with a big, expensive tile saw. Here’s the next best way: a handheld wet saw guided by a straightedge (we used a plywood scrap). The saw shown here, along with the three-step cutting method shown above, gave us perfectly straight cuts in porcelain tile (but with some chipping). A cement-mixing tub caught most of the mess.

Margin trowel

Tile setters use a margin trowel for everything: prying up sunken tiles, nudging crooked ones, cleaning out grout lines, mixing up small batches of thin-set or grout, scooping mix out of the bucket and scraping up messes. Makes a great back scratcher, too. If you’re setting tile, you’ve got to have one (sold at home centers).

Depth adjustment

If you’re using tile trim, it’s often necessary to “build out” the trim so it protrudes from the field tile. A strip of tile backer can help you get the build-out just right. Any kind of backer board will do; just slather one side with thin-set or mastic and stick it in place. Here the trim wasn’t quite thick enough to overhang the tile below, so we set the trim over a strip of 1/4-in. backer. To make adjustments of less than 1/4 in., you don’t need a strip of backer; just apply a heavier bed of thin-set.

Hand cleaner

An old shirt makes wiping your hands quick and convenient. And that keeps thin-set smudges off the tile. When the job is done, just toss it. Bet you have some shirts that belong in the trash anyway.

Tool cleaner

Thin-set today is a lot stickier and tougher than it used to be. That’s a good thing for your tile job, but not so good for your tools. For easier cleanup, toss a coarse sanding sponge (sold at home centers) into your water bucket. The grit cuts through partially dried thin-set or grout. And unlike rags or sponges, it doesn’t snag on the teeth of notched trowels.