Diagonal tile work can expand a room visually when on the floor and add dramatic accents to shower walls and bathtub surrounds. Often, tiling on the diagonal can seem daunting, especially for a do-it-yourself homeowner who likes the look but is uncertain he can align the tiles properly to achieve it. There are more cuts with diagonal tile work and preparation is important, but the benefits of the design are often worth the additional effort. The most crucial aspect of preparation is starting the first tile in the pattern. If the first tile is laid out correctly, the tiles that follow should also align correctly.
Measure the area to be tiled and mark the centre. For a wall, this will be a vertical line (use the plumb bob to ensure absolute vertical). For a floor, this mark should divide the longest side.
Draw a horizontal line on paper. For wall tiling, draw a vertical line intersecting the centre of the horizontal line. Draw a dashed line to represent the width of the grout line just above the horizontal line. Measure the tile diagonally from one tip to the other. Draw the tile diagonally above the grout line so that two points of the tile intersect the vertical line.
The important measurement is from tip to tip of the tile plus the width of the grout line. This dimension forms the measurement for the tile grid. The paper drawing will allow you to work out the tiling measurements before marking the tiling surface. The grid is formed by measuring away from each tip (using the tip-to-tip + grout measurement), making a mark and drawing a vertical or horizontal line.
Transfer the measurements to the wall and mark where each line will be drawn. Snap a chalk line at each of these marks. A plumbed chalk line will make a straight vertical line the complete length of your project. Align the chalk string with horizontal marks and snap for accurate horizontal lines. (Use a level or additional marks as necessary.)
Draw a grid pattern as directed in step 2 for a diagonal floor tile project. Mark the floor away from the centre mark using the tip-to-tip+grout measurement for all four tips of the tile because floor grids are drawn from the centre of the floor out. Snap a chalk line with the plumb bob at each mark. The resulting chalk grid will provide a guide to keep the tile in line during the tiling process.
Tile from the centre point out following the grid pattern.
Oddly cut tiles should fall at corners or along walls where they are less obvious. Walls and floors are seldom completely square so do not use them as a guide for level when creating your tile grid.