Install Subway Tile in a Shower: Step-by-Step Guide for Flawless Results

It’s about to get exciting…

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First, a quick side note: I’m a fan of Jones Soda for many reasons, including the little fortunes under the cap. The one I found recently read:

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Tasks where skill is essential — sounds like a bathroom remodel — may be accomplished. “May”? We prefer to think of our projects as definitely accomplished, not just maybe.

On to tiling. Although Sherry gave a peek at the tile job last week, here’s the full tiling story. In Chapter Three of our bathroom redo, my dad and I spent an intense four-day weekend installing drywall and cement backerboard to prepare the shower surround and floor for tile. By the time my dad left Monday evening, I had only begun tiling the shower. In fact, I was in the middle of it when this goodbye photo was taken.

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I managed only two rows that evening. Why so slow? Our tub wasn’t level, so I couldn’t use its edge as a reliable guide. We didn’t want slightly uneven lines or tiny slivers of tile along the tub or ceiling, so I spent several hours trimming small slivers off the bottom of each subway tile with a wet saw until I had a single level base line to build on. It was tedious work, but rewarding.

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I genuinely enjoy this kind of project — it asks more of my brain than my brawn and delivers immediate visible results. Since it was my first time tiling, I’ll share how I did it rather than present an authoritative how-to. There are many valid methods, and this was my learning experience.

My tools and materials included:

  • Wet saw (borrowed)
  • Tile cutter (shared purchase)
  • Buckets of thinset mortar
  • Margin trowel (borrowed)
  • Notched trowel (borrowed)
  • 1/16″ spacers (the subway tile also had built-in spacers)
  • Tape measure and level
  • Pencil and Sharpie for marking cuts
  • Paper towels and a bucket of water for cleanup

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The wet saw is essentially a circular table saw with a diamond blade that runs through water to prevent overheating and dust. It’s excellent for small adjustments, curved or irregular cuts, and cutting thick materials like marble. It’s messy, though — it produces a slurry that needs regular cleanup — so I kept it in the bathtub while working on the shower and in a drop-clothed area when cutting floor tiles.

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The tile cutter is clean and easy for straight cuts. Score the tile with the small wheel, then apply pressure to snap it along the scored line. It worked perfectly for the thin subway tiles but couldn’t handle our thicker marble floor tiles, so the wet saw handled those cuts.

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Cutting required patience and accurate measuring, while setting tiles moved faster. The main trick is using a consistent amount of thinset so tiles seat evenly without excess squeezing into the grout lines. My process:

  • Apply a blob of thinset and spread it with the margin trowel.
  • Use the straight edge of the notched trowel at a 45-degree angle to flatten the thinset into a thin bed.
  • Go over the thinset again with the notched edge to create grooves for adhesion.
  • Press each tile firmly into place and check level alignment with a level.

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A useful check is to pry up a tile right after setting it to ensure the entire back has thinset coverage — if it doesn’t, add more. I erred on the side of too much thinset in places, which caused squeeze-out in the grout lines. Clean up that excess while it’s wet using a finger, paper towel, or toothbrush; dried thinset is a pain to remove and took time with a razor blade to fix.

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After the slow start, the field of mostly whole tiles went in quickly during two long evening sessions. We almost had the grout applied the following weekend, but two setbacks — extra cleanup time and a batch of grout ruined by too much water — plus a snowstorm that delayed supplies pushed grouting to later.

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While waiting, we primed the walls with a Valspar drywall primer and chose Benjamin Moore’s Dune Grass as a color. We had Lowe’s match that swatch to their no-VOC Olympic Premium semi-gloss bathroom paint. Painting ahead of the floor tile reduced concern about drips and made the whole space feel further along—painting really did feel much simpler than tiling.

Next, we finished preparing the floor by installing cement backerboard over the plywood subfloor, using long screws driven through the backerboard, the 3/4″ plywood, and into the diagonal subfloor for a solid hold. We taped and mudded the seams, let it dry, sanded, and thoroughly cleaned the surface to ensure no dust or debris would affect adhesion.

Planning the floor layout was important: we wanted full tiles in the most visible areas and wanted to avoid awkward narrow slivers at the tub and closet entrance. With small rooms it’s often better to dry-fit tiles and shift the layout until it’s visually balanced. After test fitting, we drew guide lines to keep everything straight and consistent.

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The floor work mirrored the wall process, with an extra step: because the floor had a slight slope, we “back buttered” the tiles — applying a thin layer of thinset to the back of each tile in addition to the bed on the floor. This helps compensate for variations and provides stronger contact for heavy-use flooring like marble. We checked levelness with a level and even used a quarter rolled across adjacent tiles to see if one caught on a raised edge.

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A quick measuring trick for edge cuts: set the last full tile, place the next tile on top, and then place a spare tile on top and slide it until it touches the wall. Mark the exposed portion of the middle tile and cut. This method consistently gave accurate results.

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Because more than half of our 12″ marble tiles needed wet-sawing, laying the floor took most of Christmas Eve and a bit more time after the holidays. It was a lot of work, but satisfying to complete. I even missed using the wet saw afterward — we had some good times.

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We still need to grout and seal the tiles, so the tiling story isn’t complete yet. I’ll share the rest of the process and lessons learned in a follow-up post. Stay tuned for the grouting and sealing details and our final bathroom reveal.