Welcome back to our latest Pro-Follow update. Last time we left off, Steve Wartman and his crew had finished installing the bathroom fan, and the previous day they had hung concrete board in the shower and Fir plywood over the subfloor. At this point, the bathroom is ready for tile, and Steve called in Rick Smith and his crew to tile the shower and bathroom floor. Rick brings over 30 years of experience, and coincidentally Rick is the contractor that tiled my master bathroom several years ago.
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It’s very important to have a properly prepared subfloor because otherwise, the tile will crack and come loose in no time. The goal is to provide a flat surface with minimal deflection (bounciness). You can reduce deflection by adding extra layers of underlayment like plywood or installing additional supports under the floor.
Many professional tilers (like Rick) can judge a floor’s deflection by feel alone. For the rest of us, the Tile Council of America offers a standard formula called L/360.
Divide the total span of the floor joists (in inches) by 360 for the maximum amount the floor can give in the middle under a live load of 40 lb./sq. ft., plus any long-term deflection due to the weight of the floor.
For example, the maximum deflection for a joist span of 15′ is [15 * 12] / 360 = 1/2″.
This formula is useful for most ceramic, porcelain, and hard stone. For soft-stone tile, such as limestone or light marble, the L-720 formula applies (cutting the maximum allowable deflection in half).
When possible, Rick likes to verify the subfloor framing, and for joists spaced more than 16″ oc, he suggests using Schluter Ditra which is a waterproof, uncoupling membrane. He also targets at least a 1-1/8″ thick subfloor. Steve’s crew achieved that by installing the Fir plywood which is an acceptable underlayment even though Rick prefers concrete board.
Before starting, Steve spoke with the homeowner about various tile layouts. With that input, Steve can approximate the location of features like the shower shelves and glass listello.
Pro-Talk: A listello is a narrow, decorative tile that add visual interest to a wall.
Pro-Tip: Shower heads are roughly 82″ off the shower pan, and most layouts avoid running decorative tile at that height.
For the floor, installers often center a tile in the doorway. Steve maps out the floor and finds that a staggered layout works well because it avoids thin, small tiles around the perimeter. If that hadn’t been the case, they would have shifted the layout (perhaps centering a grout line in the doorway).
- Thinset mortar (see below)
- Tile mastic (see below)
- Mesh cement board tape (see below)
- Tile shims
- Un-sanded grout
- Sanded grout
- Caulk (see below)
- Tile (see below)
For this install, Rick and his crew are using a modified thinset mortar which has a latex additive that makes it stickier and stronger. Modified thinset is often used for tiling walls, over plywood for better adhesion, high-traffic areas and spaces that will get wet (like a shower). Thinset comes in a powder form and is usually mixed with water.
Mastic is an organic adhesive, and it’s not suitable for direct contact with water. For that reason, Rick and his crew only use it on the top-most courses in the shower. Mastic comes premixed in a tub.
Pro-Tip: Rick and his crew say that using mastic for floor tile is one of the most common do-it-yourselfer mistakes.
Mesh cement board tape
The mesh tape used for drywall will deteriorate in contact with concrete board so it’s important to use an alkali-resistant tape. Plus, concrete board tape is stronger and mold resistant.
Rick is using an un-sanded siliconized acrylic caulk that matches the color of the grout.
Porcelain and ceramic are the two most popular options for tile. Porcelain is denser and heavier which makes it tougher to cut and more difficult for wall installations. Regardless of the type, tiles can vary in size up to 1/16″ (even expensive tile from reputable dealers).
- Tile cutter (see below)
- Nippers (see below)
- 3/8″ notched trowels
- Utility knife
- Mixing Paddle
- Corded drill
- Diamond hand pad
- Saw or multitool
This is a relatively straight-forward tile job, and Rick and his crew used a tile cutter to score and snap all the tiles. They didn’t need to break out a tile saw.
Nippers are used to chew off pieces of tile, and they are especially useful for making curved cuts. A good pair of nippers is indispensable, and some of these guys have been using the same pair of nippers for 20+ years.
Diamond hand pad
A diamond hand pad is used for cleaning up a cut edge, and they used it after every cut.
Rick started the day by checking all the walls. Rarely are walls and corners square, and Rick wanted to know where the problem areas would be. He found that some of the walls were as much as a 1/4″ off plumb.
Mark Wall Center
Starting on the side wall, he marked a center line, and this is where he will start laying tile.
Rick covered all the joints with mesh concrete board tape including the joint between the concrete board and shower pan.
Next, he mixed the thinset in a bucket with a mixing paddle, and he mixed it thick enough that it wouldn’t slide down the wall.
Rick covered all the joints with a layer of thinset, and he covered the drywall mud to ensure good adhesion.
Mark Spread Line
Starting from the shower pan and measuring up the height of two tiles, Rick marked a level, spread line that will serve as a guide for spreading thinset and laying tile.
Rick spread the thinset using a 3/8″ notched trowel right up to (but not covering) the spread line.
Starting at his center line and working into the corners, Rick laid two rows of tile. Beginning in the center is important because it allows him to better conceal cut edges in the corners and it ensures a symmetrical layout.
Rick pushed each tile firmly into the thinset, ensuring good coverage. He lined up all the corners and was mindful to keep all the tiles at the same depth.
Pro-Tip: Check each tile for chips or defects, and clearly mark the defect before setting the tile aside.
Since Rick knew the areas where the walls were not square, he “cheated” a little by opening up the joints slightly to account for the difference.
Rick used the red shims to align the tiles and make sure each row stayed level. At times he would remove a tile to add extra thinset to keep everything nice and even.
Cut to Size
To cut tiles Rick would scribe a line with his pencil and either use nippers or the cutter to trim the tile.
The tile cutter has a small blade that scores the front of the tile. The wings on either side of the cutter pivot allowing you to press down until the tile snaps.
After each cut (with the cutter or nippers), the guys would clean up the cut edge with the diamond pad.
Check For Level
Rick would check on last time for level before moving on to the next section. If he found anything out of line, he would shift the tiles and/or place more shims.
Move to Next Section
This picture shows how Rick continued that same spread line to the next section.
Pro-Talk: Back-buttering refers to the process of using the flat side of a trowel to skim coat the backside of a tile, and this is another technique to ensure good coverage.
For the front and back of the shower Rick started at the corner and worked toward the inside corner to better conceal cut edges.
Pro-Talk: Bullnose refers to a rounded edge tile often used as a border because it does not expose a cut end.
Incorporating shelves into the shower is a nice feature, and Rick started the process by notching the shelf with a grinder. He cut a shallow notch just wider than the width of a tile.
Next, he scribed the outline of the shelf and used that to cut the wall tile.
Next, Rick put the shelf in place with a gentle slant to prevent water from pooling.
As he worked, Rick often cleaned the tile face with a sponge, and he cleaned his hands frequently too.
Rick and his crew had to cut holes in the tile for things like the shower controls. To do this, they started by measuring the location of the hole.
Rick used a grinder to carefully cut a square-shaped hole, starting on the face of the tile, and then completing the cut from the backside of the tile.
It’s common to add a listello or decorative stripping to make a wall of tile more appealing, and the homeowners have opted for a glass tile stripe. Rick cut the mesh backing to create pieces four rows high.
At this point, Rick and his crew could not continue with the wall tile until the thinset had cured overnight. Otherwise, the glass tiles would shift as new tiles were laid above them.
Trim Door Jamb
While the walls dried, Rick and his crew started on the floors, and they began by trimming the door jambs. They used a tile to mark the height, and then cut the jamb with a handsaw.
The guys also scraped away the old mortar from underneath the threshold.
Rick used a sponge to clean the floors which had the added benefit of wetting the plywood, and that helps ensure a good bond.
Mark Guide Lines
He traced the outline of the air register and measured a spread line off the exterior wall.
Just like with the walls, Rick spread thinset right up to his line using a notched trowel.
Floor tiles are usually separated with spacers to ensure a consistent joint. Rick doesn’t use spacers, and instead he visually sets the tile.
Pro-Tip: Leave a very small joint between the tile and the shower pan. Otherwise, even slight movement can create an irritating, squeaky noise.
Pro-Tip: Remove excess thinset that has oozed up between the tiles. You want the thinset at least 1/8″ below the surface of the tile to make room for grout.
Finish Tiling Shower
The next day, a member of Rick’s crew finished tiling the shower walls, and for the upper courses of tile he used mastic instead of thinset.
He also added a bullnose tile along the wall to act as a baseboard. For the bullnose, he back-buttered each piece rather than trying to spread mastic in such a small area.
After the tile had set, one of Rick’s crew grouted the tile. For the shower walls, they used a unsanded grout, and they used a sanded grout for the floor.
Pro-Tip: Use sanded grout for grout joints 1/8″ or bigger and non sanded grout for smaller joints.
They packed the grout tightly into the joints using a grout trowel, scraping away as much excess as possible. After the grout set up, he wiped the tile with a damp sponge, cleaning it often. He also caulked all the corners of the shower (between walls, walls and ceiling, around shower pan).
Pro-Tip: Grout all the tile at the same time. Otherwise, you may see a slight color variation due to moisture differences.