How to Install a Tile Floor

Learning how to lay floor tiles is a fairly simple process, but it's something that takes a bit of preparation. Tile comes in a variety of styles, colors and patterns. Use these tips to get started:

• Find out all you can about the types of tiles available before you decide.
• Your subfloor should be able to support tile, mortar, grout and furniture when the project is complete. It should be clean, dry and flat.
• Inspect your subfloor and correct any dips, cracks or uneven places that will cause your tile to buckle or not install properly.
• If you have a plywood or OSB subfloor, install a water-resistant cement backer board as your underlayment. Concrete subfloors typically don’t require backer board.
• Measure the area to ensure you have enough tile.
• Mix tiles from all the boxes so that minor color differences from each dye lot won’t be noticeable.

Tip: Research how to prepare a subfloor before you begin your DIY tile floor project.

When installing a tile floor, you will need a tile cutter, a
rubber mallet, tile spacers, a level, a tile trowel and thin-set mortar or another type of mortar. Thin-set is cement-based, but some mortars are labeled as “non-modified” and require a latex polymer admixture. The latex polymer admixture will improve the performance of the mortar and increase bond strength. Make sure to get the trowel size, mortar type and other tile setting materials such as spacers that are recommended by your tile’s manufacturer.

For cutting tiles, there are several tool options: a manual snap cutter, an electric wet tile saw and a tile nipper. The manual snap
cutter is generally used for smaller jobs. For jobs that require cutting many tiles, a wet saw is best. For specialty cuts around things like plumbing fixtures, pipes and round corners, a tile nipper comes in handy.

Tip: For one-off projects and DIY home renovations, consider our mud mixing drill and tile saw rentals.

When tiling a floor, draw a layout of your finished tile design directly onto your subfloor.
The layout’s lines show you where to start laying floor tiles and help ensure the tiles are properly
centered in the room. Layout lines must be square, otherwise you will end up with odd-shaped tiles at the walls.

• The best way to ensure square lines is to make a floor plan by drawing the walls of the room as accurately as possible on a sheet of grid paper. Include doorways and floor obstructions such as cabinets and fixtures as well as any tile edging or trim.
• Find the center point of the room: Measure the four walls for their midpoints.
  Snap two chalk lines, one from the midpoints of two opposite walls, and another from the midpoints of the other two walls. The room’s center point is where the
  lines intersect.
• Check that the chalk lines are square: Mark points 3-feet on one chalk line and 4-feet on a perpendicular chalk line starting at the intersection.
  Measure the diagonal space between each of these two points. If the distance between the two is exactly 5 feet, the lines are square.
• If the lines are not square, the tiles will be off-center, and the room might look unbalanced. If the room is not square – which is common – you will need to adjust the position of one line, and then square the other line using the 3-4-5 procedure mentioned above.

Tip: Make a floor plan and mark the dimensions of your scale. For example, 1 inch gridline = 1 foot of floor space.

Test the layout you’ve designed by doing a dry run with your tiles.

• Lay a single half row of floor tiles in both directions without mortar, starting at the center point and working outward. Some tiles have directional arrows on the back. You must keep these arrows pointing in the same direction to ensure pattern alignment.
• Insert spacers between the tiles.
• Stop when there is not enough room for a full tile. If the space at the end of either row is smaller than a third of a tile, adjust your chalk lines so that the space on either side of the room can accommodate at least a half of a tile.

Thin-set mortar is a common bonding agent used to attach tiles to the backer board or concrete subfloor. It is made of cement and fine sand and will need to be mixed with water if bought dry. Mix your thin-set in a large bucket using a drill with a mixing paddle, following the package directions. Keep in mind:

• Mortars cannot be used immediately and must be allowed to stand for five to 10 minutes after mixing. This is known as “slake time” and allows the chemicals in the mortar to fully activate.
• Take care not to mix too large a batch of thin-set. It has a limited working life, and if you’ve mixed too much, it will start to harden before you’ve had a chance to use all of it.
• Clean the mixing paddle promptly after use so the mortar does not harden on it.
• Porcelain tile must be installed using a polymer-modified thin-set to achieve the right bond between the tile and the substrate.
• When laying tile onto backer board, wet the backer board using a spray bottle filled with water before spreading the thin-set. Spray the backer board as you work, otherwise the backer board will soak up water from the mortar, causing the mortar to dry too rapidly. This will impact how well your tiles adhere to the subfloor.

Tip: Do not add water after the thin-set begins to harden. Doing so weakens the mortar and severely affects the bonding between the tile and substrate.

Tile trowels have both a smooth edge and a notched edge. The notches are called teeth. The depth and width of the teeth of your trowel depend on the type and size of the tile. The size of the notch determines how much thin-set is left on the floor under the tile. Typically, the larger the tile, the larger the notch should be.

• Use your trowel to scoop out a generous amount of mortar from your mix bucket.
• When you’re ready to start applying mortar, spread the thin-set with the flat side of the trowel. Press it into the backer board or subfloor at roughly a 45-degree angle. This will ensure the mortar fully adheres.

Tip: Follow the tile manufacturer’s recommendations when choosing a trowel.

At the beginning of your tile floor installation, always do a test to ensure the consistency of the mortar is appropriate.

• Spread thin-set onto a small test area at the center of your layout.
• Put the first test tile onto the thin-set bed. Lay the tile flat and then with mild pressure, slide the tile 1/4-inch back against the thin-set ridges, then slide it back into place.
• Pull the tile up and check the back of the tile. It should be completely covered with thin-set.
• If you have areas on your test tile that are not covered with mortar, it means you didn’t mix the mortar properly, didn't spread the mortar evenly or waited too long to set your first tile and the mortar started to dry. It may also mean you didn’t evenly and firmly press the tile into the mortar. Correct as necessary before you proceed.
• Once you’ve confirmed you have the right mortar consistency, re-lay your first tile. Make sure
  it lines up with the chalk lines at the layout’s center and that it is fully pressed back into the mortar.
• Place two spacers along the side where you will add a tile, one on each end. Spacers help
  ensure equal spacing between tiles. Always position your spacers so they stick up and out. A common mistake is to lay them on their side in the corners where four tiles meet. If you do this, they become embedded in the mortar and can be hard to remove.
• Set your second tile by aligning the edges and corners
  then
  hinging it down. Twist it back and forth slightly as needed for an even alignment and secure placement.

If this is your first time tiling a floor, you may only want to apply enough mortar for one or two tiles at a time.

• Comb the thin-set using the notched side of your trowel, holding it at a 45-degree angle and lightly pushing the trowel teeth to the floor.
• Make sure you comb the thin-set in one direction. Avoid circular or swirling patterns. The combed channels will flatten out and compress when the tile is placed, ensuring the proper amount of mortar is present beneath the tile.
• Use a small, thin trowel to remove a small amount around the edges of your tiles as you go. Do not allow the thin-set to skim over or start drying as you go. If it does, remove it and apply a new layer of thin-set.
• As you lay each tile, check them for dirt or dust. Wipe them clean if needed. The dust can affect how effectively the tiles adhere to the mortar.
• Throughout the process, use a damp sponge to clean off any mortar that ends up on top of the tiles. Do not let it dry. Once dry, mortar on tile is extremely hard to remove.

Tip: Always follow the chalk lines of your layout to ensure you're laying tiles in a straight line.

After installing three or four tiles, make sure they are level.

• Place a 2 x 4 on top and tap lightly with a rubber mallet. This will level the tiles and embed them firmly in the mortar.
• Continue spreading mortar and setting additional tiles.
• Check your alignment by stepping back every so often and looking down the tile edges to be sure the lines are straight. This should be done often, before the mortar starts to dry and harden.
• If you find alignment issues while the mortar is still wet, you can straighten them before continuing.

Finish laying tiles in your first quadrant. You’ll then be left with the space between those tiles and the wall where cut tiles are required. Finish laying all full tiles in your other three quadrants and let the mortar harden.

Different mortars have different curing times, but most require you to stay off the tile for 24 hours. If you need to take a break when installing floor tiles, always scrape up any mortar overlapping into an area you are about to tile. If left to dry, it will affect how well those new tiles adhere when you return to work those areas.

Tip: Plan your flooring installation so that you have an exit without stepping on any tiles before the thin-set hardens in about 24 hours.

Measure and
cut the tiles to fit the space left along the wall.

• Leave an expansion gap between the tiles and the wall as recommended by the tile manufacturer. This will allow the floor and grout to expand without causing cracks. It will also account for the space needed for the grout line.
• Lay out, mark and cut small groups of tiles at a time and leave them in the space where they will be installed.
• Measure twice before you cut.
• Install cut tiles in small groups to avoid mixing too much mortar and risking it drying out before you can use it all.
• To cut a curve, mark the cutting line, then cut away bits of tile with tile nippers. Smooth the cut edge with an abrasive stone.
• When tiling with natural stone or porcelain floor tile, always cut with a wet saw to prevent breaking or chipping.
• When cuts aren’t clean, change the tile saw blades.

Once your tile floor is complete, it's time to apply the grout. Grout fills the spaces between the tiles. Like paint, grout can come in a variety of color options that match or complement your tile.

• Before grouting, remove all your tile spacers. Leaving the spacers in place and grouting over them will compromise the integrity of the grout.
• Protect baseboards, trim and neighboring floors with painter’s tape.
• Mix grout according to package directions.
• After the grout is ready, spread it in sweeping arcs with the rubber grout float held at a shallow angle.
• Apply at a 45-degree angle to the spaces between tiles to prevent the float from pressing into the spaces and creating uneven grout surfaces.
• Press grout into the joints, filling them completely. Focus on small 4-by-4-foot sections.
• After the grout is spread, remove the excess with a grout float held at a 45-degree angle. Work diagonally across the joints to avoid dipping into the joints.
• Mist the grout twice a day for three days to slowly cure it. Do not walk over the surface for eight to 12 hours.

There are several types of grout, and different grouts require different methods. For example, almost all cement grouts have latex polymer in the powder mix. Others require a latex polymer admixture.

For joints 1/8-inch to 1/2-inch, use sanded grout. For joints up to 1/8-inch, use non-sanded grout. Follow the tile manufacturer’s recommendations.

If there are gaps between the tile and the wall, be sure to fill the space with caulk to keep water from getting under the
tile or into the wall. Caulk will be the easiest to use in this case, as it will fill the gap and stick to the tile face while remaining waterproof. It also won't crack and can be replaced easily. While you can also fill the gaps with mortar or grout, it is not as flexible, waterproof or easy to repair as caulk.

When tiling a floor, be careful to remove excess grout promptly to avoid grout haze. Grout haze happens when grout dries on a tile, dulling the finish.

• Take a damp sponge and make light passes across the tiles diagonally to clean off the excess grout.
• As soon as one section is complete, wring the sponge until no water drips from it before cleaning. Excess water can affect the consistency of the grout.
• Use both edges of each side of the sponge. Be careful not to press the sponge into the gaps. Do as many passes as needed. The drier the grout is on the tile surface, the harder it is to remove.
  The tiles won’t be clean on the first pass so be patient.
• Rinse the sponge frequently in clean water and also change the water frequently. The cleaner the water, the more effectively it will remove the grout from the surface of your tiles.
• Remove any remaining grout haze by using an old T-shirt or cheesecloth. If you have trouble, try adding a grout haze remover solution.
• Try to remove all the haze before it dries completely and becomes harder to remove.

Sealing your grout is essential to keeping grout lines clean and looking like new. Grout sealer provides unsurpassed, invisible protection for grout. Sealers help prevent stains and keep mildew and mold from growing into the grout.

• Choose a sealer with a built-in applicator or pick up a grout sealer application bottle. You can also use a grout additive that provides stain resistance during the curing process.
• Wipe up any excess sealer within 10 minutes. If you’re using glazed tile, be extra careful to only seal the grout.
• Follow the manufacturer’s instructions on when to apply your sealer. In most cases, allow the grout to cure for about three days before using a sealer.

Tip: Expect your grout sealer to last an average of one to two years before needing to reapply it. If you drop water on existing grout and it seems to soak in, it’s time to reseal.

• To finish your project, remove the painter’s tape from any protected surfaces.
• Cover the 1/4-inch expansion gap left along the walls. You can do this with either matching bullnose tile trim or wood quarter-round moulding.
• Add any desired thresholds between your tiled floor and neighboring floors.