After the substrate selection has been made, the key element in a good countertop installation is the layout. The layout will depend on several considerations. These include the type of sink that will be used; accent tiles used, and trim use. Also, will the tile be set in "soldier" courses meaning straight in line or on the "diagonal"? As detailed in The Tile Doctor section on "Estimating/Layout", full tile is the goal. When tile must be cut, the larger the cut the better. Generally, the sink should be centered in the field of tile. Trim should also be centered on the sink. The choice rests with the installer.
For an attractive countertop, layout is critical. Careful planning is the key. The first thing to decide is whether the deck will be set on a diagonal or in a soldier course. If the top is to be set on the diagonal, the installer has the benefit of not having to match grout joints where the deck meets the backsplash. The same is true if the backsplash tile is larger than the deck tile.
Set on a diagonal
Set in a soldier course
The first step to layout is the working lines. The first line should be along the leading edge of the countertop. This line is established by measuring the depth of the trim selected. For example, many v-caps inside top edge measure 1-1/2″. Subtract 1/8″ for the thin set used to back butter the inside front edge during installation. Then add the grout joint size. This measurement is used to place the first line down the longest countertop edge. It represents the exact spot where the field tile will start. To place this line, use the measurement in two places along the longest run, one at either end. Then use a straight edge and pencil to make the line. At this point check along this line to insure that there is enough room for the trim piece and thin set mortar. If there is not sufficient room at any point, adjust the whole line further out. Remember to keep the line straight with the cabinet or shelf.
If the countertop has a 90 degree return, extend the line past the edge onto the opposing deck. Repeat this step with the opposing countertop space. The idea here is to have two crossing lines that meet at the 90 degree corner.
The installer now can adjust these lines to be square to one another and can verify enough room exists for the trim and mortar backing. The necessity of installing the cabinets or shelves square with one another is quite evident here.
After the first line or lines are established, the installer needs to determine where to start the tile courses. It is generally a good idea to have full tile whenever possible. Tile smaller than 1/2 the width may not be visually appealing. A good idea, especially for the novice, is to make a series of "dry runs" prior to installing the mortar bed. In this way, the installer knows and can mark exactly where the field tile will end and where the trim begins. Generally, in 90 degree countertops the first tile is set in the intersection of the two crossing lines. The tile runs out in either direction from there. Most of the time this will work out. However, the distances should be examined to make sure that it would.