How to Calculate a Tile Subway Pattern in a Tub
Subway tiles are rectangular-shaped tiles that frequently measure 3 by 6 inches in size, but they are available in numerous other sizes as well. Typically installed in an offset pattern or running bond, they come in numerous materials and colors, and can be installed anywhere in the bathroom. Subway tiles work well in shower surrounds, tub surrounds, tub decks and even for the tub itself, if it's being tiled. Calculating the amount of tiles and the layout for each of these areas is identical, provided that proper measurements of each space are taken.
Calculate the amount of subway tile for the shower surround above the tub by measuring each wall horizontally and vertically in inches.
Multiply the two measurements for each wall together and divide by 144 to get the total number of square feet needed for each wall of the surround. Add the three walls together, and then add an additional 10 percent to the total to accommodate the cuts and edges of the running bond pattern. There are eight 3-inch by 6-inch subway tiles in 1 square foot. This means that a tub surround measuring 72 inches high, with two walls measuring 30 inches and one measuring 60 inches, requires 66 square feet or 528 subway tiles if you're using standard-size tiles.
Measure each of the side walls vertically from the tub to the ceiling in inches and divide by 12 to get the number of linear feet of bullnose, or finished edge pieces, needed to complete the tile job. Subway tiles are available with the bullnose on the short side of the tile. To complete a job with 72-inch-high walls, you'll need 12 linear feet or 48 pieces of 3-inch by 6-inch bullnose subway tiles with the finished edge on the short side.
Calculate the amount of subway tiles for a tub deck by measuring the height and width of each of the visible front or side panels of the tub surround in inches. Multiply these measurements together and divide by 144 to get the total number of square feet needed for the facing sections of the tub deck.
Add up the sections of tub deck facing if applicable, and add an extra 10 percent for waste to accommodate the subway tile pattern.
Measure each of the four sections of the top of the tub deck. Measure from the length of each section in inches, and then measure from the edges of the deck to the tub cutout. Multiply these two measurements together for each of the four sections, and divide each one by 144 to get the amount of square footage needed for each section of the top of the tub deck.
Add the four sections together, and then add an extra 10 percent to accommodate the subway pattern.
Measure the front edge of the tub deck wherever it will turn at a 90-degree angle down to the tub face lengthwise in inches, and divide by 12. This will be the amount of edge tiles needed to make the transition from the top of the deck to the face of the deck. The finish tiles used here should be bullnosed on the 6-inch side. If the tub requires edging on the front face only and is 72 inches long, 6 linear feet or 12 pieces of finish tile are required.
Measure the depth and length of each of the four interior walls of the tub in inches. Multiply these two measurements together and divide by 144 to get the amount of subway tiles needed for the tub interior.
Add the measurements for the four walls of the tub together, and add an extra 10 percent to accommodate the pattern.
Measure the interior top edge of the tub in inches on all four sides where the interior of the tub meets the tub deck. Divide this measurement by 12 to get the amount of finish edge tiles to go around the tub's perimeter.
- Start laying the tiles with your first subway tile in the bottom center of the longest wall of each section. Move up and out from there to get the most balanced subway tile running bond pattern.
- Subway tiles are commonly sold in full boxes of 10 square feet, or 80 tiles per box. Round up your calculations to the next nearest full box to ensure that you have enough tiles to cover the job.
Sarabeth Asaff has worked in and has written about the home improvement industry since 1995. She has written numerous articles on art, interior design and home improvements, specializing in kitchen and bathroom design. A member in good standing with the National Kitchen and Bath Association, Asaff has working knowledge of all areas of home design.