If you’ve been covering your bathroom floor with mats by necessity rather than choice, it’s time to tackle the floor — and you can do it in one DIY weekend. First and foremost, “you must get the right materials,” says Tom Silva, general contractor for the PBS show Ask This Old House. Every tile (ceramic, stone) or floor (cement, plywood) is different and requires different material. “Nine times out of 10,” Silva says, “problems arise because someone cut corners and used the wrong mastic (adhesive) or laid tile on a floor that wasn’t completely flat,” which leads to crooked and unstable tiles. If your existing tile floor is tight and in good shape, Silva says, you can save yourself a headache by deglossing the tile with heavy sandpaper and just tiling over it. Lay all the tiles out on the floor ahead of time to be sure you like the look of the whole layout, that it’s going to lie straight, and that you have enough tiles to finish the job. Then start your tiling in the center of the room so you can work out any errors as you move outward toward the walls.

After you apply adhesive on the back of a tile, run a comb trowel or a notch trowel through it to create uniform ridges. This step is vital, says Karan Sanford Taylor, a kitchen and bathroom specialist for Home Depot, “so that when you put the tile down, every part is perfectly, evenly supported — an 1/8-inch difference is a big deal in tiling.” For the same reason, you should put the tile down flat in one clean shot, says Taylor, who recommends using plastic tile spacers. “Don’t put one edge down first and then drop the rest,” she says. “And don’t slide the tile into place after you’ve pressed it into place.” Silva recommends adding a bead of watertight sealer between the tub and the substrate (the floor beneath the tile) before you place the tile down and caulk it so water can’t leak through and eventually rot the floor.

Finally, when it comes to grouting, timing is critical. Wait a full 24 hours after tiling, then “grout diagonally across the tiles,” Silva says, so it compacts easily into the joints. Wait another 24 hours before sealing the grout and walking on the floor. You should consider hiring a professional if the floor you’re tiling is damaged or rotting, the tiling design is highly detailed, or the job requires cutting a lot of rounded corners. “Basically,” Silva says, “if you’re thinking you might need a pro, you probably need a pro.”