Remodeling 10: How to Lay Ceramic Tile

Floor Tiles

Ceramic tile is designed to be laid over concrete floors, but we can lay the tiles over wood floors if the necessary preparations are done first. In new construction, it is common practice to install a second sheet of 5/8" plywood over the existing sub-floor of 5/8" tongue and groove plywood, giving a total thickness of 1 1/4". Older houses that have 3/4" shiplap for their sub-floor and also a layer of 3/4" hardwood, don't need the second sheet of plywood. Just roughen the surface up with a belt sander for better adhesion of the mortar. For those floors with a layer of vinyl flooring or tile, rather than try to tear it off and leave chunks of tile and glue behind, I would cover it with 1/4" structure wood (or plywood) designed for underlay of vinyl flooring. Nail it down every 4" or 6" on center, according to the manufacturers instructions. The main point here is to have a good, strong, thick area for the ceramic tile to rest on. Ceramic tile does not have to bend or flex much before it cracks, so we want to lay it on a surface that is solid. Concrete floors can be patched and any depressions filled with floor levelling compound made specifically for concrete.

If the floor you are covering is in the bathroom, lift the toilet up and clean the area around the floor flange well. After the grout is dry re-install the toilet with a new wax seal. Refer to my article Removing and Replacing Plumbing Fixtures for more details. Don't bother trying to get under the tub or shower, just come to it and after grouting apply a bead of silicon caulk on top of the ceramic tiles and against the tub or shower skirt. If in a bedroom, remove the closet doors and main door, you will find this easier to work around.

Ceramic tile is sold by the square foot, no matter what the actual size of the ceramic tile itself. No need to figure out how many ceramic tiles you need, just figure out your area to be covered and go see your ceramic tile outlet for samples and costs for your particular area. They will advise you of the thin set mortar and grout needed for your particular job. Also, buy your correct notched trowel, sponge float and sponge for the grout while you are there. Other tools you need is a ceramic tile cutter (purchase or rent), a ceramic tile wet saw (rent) or angle grinder with diamond blade. Ceramic tile nippers and grout remover may also be handy. There are mortar and additives (bonding agents) to enable you to install the ceramic tile right over an existing surface of ceramic tile or vinyl flooring, providing these surfaces are in good shape and stuck down well. So inform the salesperson of your particular job and include the details so they can advise you appropriately. They will suggest the choice and colour of grout for your ceramic tiles; ceramic floor tiles have a sanded grout that stands up better for foot traffic. Ceramic wall tiles use a non-sanded grout. Watch when installing your sanded grout around hardwood or finished wood. As the name 'sanded' implies, it is rough on finished wood. When grouting next to hardwood or painted wood, I try to make sure the wood is either covered with a couple of coats of Varathane® clear finish or painted with the finish coat of semi-gloss paint. The cement in grout has the ability to turn un-finished hardwood, especially oak, black when in contact with it. Having the oak pre-finished will alleviate this problem. Have a damp rag handy to keep it clean.

Ceramic Floor Tile Layout

Okay, you have your ceramic tile all piled up in your kid's basement bedroom, the floor is secure, nailed up and tight with the correct thickness, or the concrete is clean and any holes patched. Let's start the ceramic tile layout.

Measure the room or area for the center of the room in both directions. Lay the ceramic tiles down on the floor—dry (no mortar), up against the center mark. Leave the space you want between them and actually see where the ceramic tiles will come and see how much of a ceramic tile you need from the full tile to the wall. If this is a sliver or narrow piece, center the ceramic tile with the center mark, rather than up against it and lay the ceramic tiles out again. Refer to this drawing.

Diagram showing how to layout a tile floor using the center line of the room.

The space between ceramic tiles is variable from about 1/16" to 1/4". 3/16" is an average spacing. There are ceramic tile spacers available, but I tend to shy away from these. One reason is if you tend to wander off the line or need adjustment to get back on, forget about the spacers. Novices get too dependent on them and if the ceramic tile is running out, spacers won't let them correct the situation. I'm talking about a sixteenth here, not a quarter of an inch. The point is try to keep your line straight and give up the spacing to do so, within reason, of course. Laying ceramic tile is a visual thing; keep the lines straight and spaces even as much as possible.

When you have determined where you are going to start, whether on the center mark or beside it, let's lay out the ceramic tile lines. Place the ceramic tile where you want it and mark one edge of the ceramic tile. Take a measurement from this mark to the side of the long length of the room and transfer marks at each end of the room. Determine the difference, if any, between the sides of the room and split any difference. Snap a chalk line between these two marks. Next determine where the ceramic tiles will go for the short dimension of the room by following the same procedure. Place the ceramic tile on the side or center mark, with one edge of the ceramic tile along the snap line. Mark the edge of the ceramic tile.

This cross line has to be square with the snap line already on the floor. To do this, either use a 4' drywall square, do the 3, 4, 5 measurements or very carefully and precisely lay the ceramic tiles out 90 degrees with the snap line. Keep the ceramic tiles tight together and in line. This isn't a very accurate way of squaring a line so check it again for square with the 3, 4, 5 method. Remember in school we learned about Pythagorus' Theorem, that with a 90 degree triangle the sum of the area of each side equals the area of the hypotenuse. That's where we get the 3, 4, 5 method. If one side is 3' or 6' or 9' and another side is 4' or 8' or 12', the hypotenuse (the side opposite the 90 degree angle) is 5', 10' or 15' respectively. Do the math (a2 + b2 = c2, where a = 3, b = 4 and c = 5) or take my word for it. Okay, now we have a line near the center line of the room in both directions and these lines are square with each other.

Where's the door? Don't tile yourself into a corner like a painter. Start on the quarter of the room away from the door, so you don't have to walk on the ceramic tiles to get out. Don't walk on them for at least 8 hours. The reason I start in the middle of the room and on one side like this is that it cuts the possibility of error in half. Rather than starting at the end of the room and proceeding to the other end, start half way and lay the ceramic tiles towards the walls, away from the door.

Mix up the thin set mortar. A power mixer with a 1/2" chuck works well. Start with water in a five gallon bucket, add your mortar, stir it up and add more until all of a sudden it is a thick even paste. Set your timer for 10 minutes. In the mean time clean up the mixer tool right away and leave the mortar to slake for 10 minutes. These instructions should be on your bag; follow your bag's instructions if they are different than mine. If you have the special circumstance of having to add bonding agent then just use the liquid bonding agent without water. There again follow the instructions that came with your mortar and bonding agent. Alright, the bell tolled for the end of the 10 minutes, let's get to work.

Apply the mortar with the proper trowel. Do a small area at a time, don't let it dry out before getting the ceramic tiles on. Start on one side of the line, don't cover the line with mortar; just come close to it. Place your first ceramic tile's edge on the line and work towards the wall. Lay the ceramic tile down into the mortar and give them a slight twist into position. The mortar should be applied leaving small peaks and valleys created by the trowel. Scrape the trowel's edge down to the floor to keep all the peaks the same.

Do a couple of rows, then cut the ceramic tile against the wall to fit. Most ceramic tile cutters have an edge guide so you can set it and cut more than one ceramic tile the same size. Allow for the space when cutting the ceramic tile. Try to get as close to the wall as possible, remember that the base board will cover 3/8" or so, depending on what you buy. Adjust the guide on the ceramic tile cutter if you notice the spacing is getting a bit out. I find very useful a small length of 3/4" stock about a foot long and 2 or 3 inches wide. I use this to run along the snap line side of the ceramic tiles to keep them straight, then along the 90 degree edge of the ceramic tiles themselves. If the block moves along the ceramic tile line smoothly without bumping into a projecting ceramic tile the lines remain nice and straight.

Another trick I use is to measure from the edge of the ceramic tile to the opposite ceramic tile including the space between them. As the ceramic tiles are laid out and the area gets larger, take a few measurements from the snap line to the ceramic tile against the wall and from the starting cross line to the end of the square you've just done. If everything measures out the same in both directions and the ceramic tiles are straight along the snap line and the cross line, obviously the spaces are going to be even and straight as well. This is how I get away with not using spacers. I also sight along the ceramic tile line continually. Get your eyeball right down there on the floor and look along the line of ceramic tiles. Better to move the ceramic tiles a bit now than after they are held in place with the dried mortar.

If you come to a stopping point where you have to cut a ceramic tile on an inside corner, make sure you scrape any mortar off the floor before it dries with the smooth side of the trowel. Were you wondering what that side and end were for? I usually do all the full and part ceramic tiles that can be done with the ceramic tile cutter first, then mark all the inside corners at one time and take them outside and cut them. You can rent the ceramic tile saw for cutting these inside corners or you can take them down to your ceramic tile supplier, who will cut them for you for a fee. You can also purchase the ceramic tile saw, but it is pretty expensive for one job. I bought a little ceramic tile blade, 4 1/2", for my angle grinder that works very well. Cost is about $50 for a diamond blade, but was well worth it. A carborundum blade on a table saw doesn't work very well compared with the diamond blade. When you get near the end of the wall, remember to add the cut ceramic tiles and corner ceramic tile while there is still room to get in there. We don't want to walk on the ceramic tiles now.

Okay there you have it, one side of the room is done. If you want to do the other side before the ceramic tiles are dry enough to walk on you will have to transfer a line near the wall, at the opposite end of the room to the door, so you can reach this row as well as the cut row against the wall. You know exactly where this row will be; just measure the ceramic tile line on the existing row from the cross line and transfer the line over with a snap line. Start laying the ceramic tiles on this line and cut the ceramic wall tiles before you can't reach them. Now aim towards the door. If the closet is further away from the door in a bedroom do this first, leaving the area in front of the door until the last.

Now, leave the ceramic tiles to dry over night and get ready for the grout in the morning.

Grouting is easy, but time consuming. Before mixing the grout, check out the ceramic tile job. Check to be sure no mortar is oozing out of the grout joints. Scrape them clean, there is a tool for this or use a screwdriver or knife. Vacuum the ceramic tiles and joints clean. Wet your sponge and dampen the face of the ceramic tiles removing any dust as well. Mix up the grout as you did with the mortar and let it slake as well for 10 minutes or so.

Dump the bucket of grout on the ceramic tiles and spread it out and into the joints thoroughly using the sponge float. Work at a diagonal to the joints, scraping off as much grout as you can with the float. Use up the grout in your bucket. If the grout on the surface of the ceramic tile is drying, wash out the grout bucket and bring some fresh water and your sponge into the room. Wipe off the excess grout from the face of the ceramic tiles, continually rinsing the sponge off with clean water. At the same time as you are washing the surface of the grout, you are smoothing the grout lines. Don't do this too early, otherwise you'll remove the grout, but just work the grout lines until they are smooth and even. A slight residue of grout on the ceramic tiles is okay, this can be wiped off tomorrow with a dry cloth. Just be careful that if you used a dark color for the grout and the ceramic tile is a light color with a rough texture, the grout doesn't stain the ceramic tiles. The shinier the ceramic tiles, the easier the grout will come off. Just be aware that a flat finish, textured ceramic tile may be stained by the grout especially along the grout lines.

That's it. In eight hours or so, wipe the ceramic tiles clean with a dry rag and enjoy your new ceramic tile floor.

Ceramic Wall Tiles

As with the ceramic floor tiles the surface on which ceramic wall tiles are mounted must be in good shape. Ceramic tiles for a shower should be installed on cement board with a transition to drywall near the top and sides. Mud the joints and prime them with sealer before installing the ceramic tile. Around a cabinet, back splash drywall backing is okay as long as it is primed first, plywood is also acceptable. There is plastic edging available to trim up a back splash or shower top. There are, of course, edging ceramic tiles with a rounded over look that are very expensive compared to the rest of the ceramic tile. Silicon caulk is also an option for finishing the edge of ceramic wall tile. I prefer plastic trim, especially if the ceramic tile is white. Your ceramic tile supplier can show you these products to compare their aesthetic value to their monetary value.

Ceramic wall tiles are installed with an adhesive rather than a mortar. Here, as with ceramic floor tile, get the appropriate notched trowel, they are not the same tool. The sponge float and sponge can be used for both jobs, however. As with the ceramic floor tile, layout your ceramic tile wall and see where the ceramic tile will be centered, whether on the center line or beside it. For a shower, I lay the full tiles on the outside edge of the wall and cut the ceramic tiles to fit the inside corner. Start at the tub or shower rim with a full ceramic tile and go up from there and stop about 72 to 76 inches from the floor. This allows the arm and flange of the shower head to be above the ceramic tile at 78". If you want the ceramic tile to go tight to the ceiling, I would start with a full ceramic tile at the ceiling and cut the ceramic tile at the rim. Watch this, though; you don't want a thin sliver of a piece to cut at the rim, so in this case add a cut piece at the top and bottom. That is why a layout is so important before you start tiling. In a shower, feature ceramic tiles are sometimes added, especially if the ceramic tiles are white or a basic color. They are usually added randomly or in a pattern, so lay them out accordingly.

As with ceramic floor tiles the wall should be laid out and a starting line snapped near the center of the wall. This line should be plumb. A level line should be drawn, as well, for reference. Don't go by the tub rim, they are usually sloped toward the drain. Check this out first to be sure, in your case.

On a ceramic back splash for a bathroom or kitchen counter top, the ceramic tops are usually installed dead level, making it easy to start with a full ceramic tile resting on the counter top. Install all the full ceramic tiles first, then mark and cut the part ceramic tiles around plugs, faucets and taps. If the faucets and taps or shower control are already installed, try to remove the trim first as it makes for a nicer job if the ceramic tiles go behind the trim. These pieces do come off; it may be a trick though to figure out how. The tub faucet will either unscrew or has an allen head (hex head) set screw on the underside that needs to be loosened. Also, remove the cover plate for wall plugs and lift the receptacle flush with the ceramic tile before re-installing it. One trick is to use small nuts and washers as spacers under the two screws that hold the receptacle to the box. I've also cut short lengths of 3/8" OD (outside diameter) tubing as spacers.

For rounded objects like faucets and taps, I find the angle grinder with the diamond blade great. Use ceramic tile nippers also as a tool for this purpose and clean the edge up with a file or grinder.

Grout the ceramic tile the next morning and follow the same procedures as outlined for ceramic floor tile.

Take a step back and savor the moment. Good job!


(Ask Dave) (About Dave)

Your source for building tips, woodworking & furniture plans, house plans and building advice directly from Dave...

Hi, I'm Dave Osborne. With over 50 years experience as a journeyman carpenter, foreman and contractor in heavy construction I enjoyed working with apprentices and sharing the tricks of the trade that others shared with me. Now I get emails from Members all over the world and we include many of my answers in our Free Monthly Newsletters. Some of my answers include drawings and instructions specific to a project, but may also answer your questions. I use correct construction terminology, so you can confidently inform your building supply dealers or contractors exactly what you need.


The Benefits of Membership

Membership gives you full access to our hundreds of how-to articles, woodworking plans, converters, calculators and tables. Our Stair Calculator is one of the most popular on the internet. We have projects you can build for (and with) your kids, furniture for your wife, and sheds and gazebos. If you run into a problem or need advice your Membership includes unlimited email questions to me through our Ask Dave quick response button.

Join us!