Countertop Tile Foundation

DEAR MIKE: I'm going to replace my counter top with ceramic tile and so I have removed my old laminate one leaving nothing but the cabinets below. I have done some small floor tiling projects, but never a counter top.
I'm going to reuse my drop-in sink and faucet, but how do I go about building the base that the tiles will sit on? -- Kevin H.

DEAR KEVIN: Tiling a counter top is like building a house: if the foundation is weak, you are going to have problems. Once the foundation is down, the tiling part of the job goes pretty quickly.

You are going to lay down a three-quarter inch sheet of plywood and, depending on the height of the edge tiles, lay down a sheet of one-half inch cement board on top of it. This whole mess will be mortared and screwed together.

Start by installing ledger boards on the perimeter walls if there is no support there, and screw the ledger boards to the wall studs.
Cut sheets of three-quarter inch plywood to sit on top of the cabinets so that the edge of the plywood sits evenly with the frame of the cabinets. Drill pilot holes in the top of the cabinet frame and screw the plywood to the frame and along the ledger boards.

Now, check out the height of the edge tiles. These are called "V" caps and have a rounded edge that transitions the horizontal surface to a vertical one. If the height is such that they may interfere with the operation of the doors, then you will need to add an additional layer of plywood. If this is necessary, use construction adhesive and screws.

Flip your sink upside down on the plywood and make a mark around it. Remove the sink and make another mark inside the first line so that the sink rim will have enough area on which to rest. Drill a hole inside this second line and cut out the area with a jigsaw.

As a final step for the base, lay a sheet of one-half inch cement board on top of the plywood. Trowel a layer of thinset mortar on the plywood and screw it down. You can cut the cement board by scoring one side and snapping it or by using an abrasive blade in a jigsaw.

You will also want to reinforce the edges, so add a strip of cement board equal to the thickness of the base. Use galvanized nails to secure it and then wrap the edges with fiberglass tape before embedding it in a thin layer of thinset mortar.
Now you're ready to lay out the tile.

There are no hard and fast rules for tile layout except that you want to avoid thin pieces of tile. Pick a spot that is highly visible and start by laying out tiles across the surface. If your counter changes direction rather than just a straight run against the wall, a corner area is a good place to start.

Some tiles have built-in lugs to keep them evenly spaced and some will require you to install spacers (or you can just eyeball the spacing). Lay out the tiles and use a framing square to make sure the lines are straight. You can snap chalk lines and lay one row in each direction.
If you end up with a thin piece of tile on one side, move the tiles over to eliminate the slivers. Then you can snap a new chalk line.

Mix up a batch of thinset mortar and trowel it on with a square notched trowel. Lay the tiles in sections. When you have completed one section, move to the next.

When it comes time to cut a tile, you can rent a wet saw or you can buy a cheap one for less than $100 and it will work great for this job.

When it comes time to install the V-cap tiles, you can clamp a board to the cabinets as a place for the tile to sit against until the mortar cures, or you can tape the V-caps to the tiles in front of them.

For the backsplash, either line up the grout lines or make the backsplash tiles line up halfway between the field tiles. Let the mortar cure according to the manufacturer's specifications (usually 24 hours).

To grout, you'll need a grout float (a piece of rubber attached to a handle), bucket of water, large sponge and dry white rag. Mix the grout, then use the grout float to push it into the spaces between the tiles. Keep the face of the float at an angle and pull it diagonally across the face of the tiles filling every nook and cranny.
Wring out the sponge in clean water and wipe up the excess grout. When the sponge gets clogged with grout, dunk it in the water and wring it out.

About 15 minutes after you sponge off the grout, you'll notice a haze forming on the tile. Use the rag to buff it off. You should do this promptly.

Reinstall the sink and lightly mist the grout with water for three days to help it slowly cure. 

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