I am installing 4x4 ceramic tiles on a shower wall. I have been using a 1/4 x 1/4 sq. notch trowel, but am having trouble with the tiles staying put...should I use a 3/16 x 5/32 v-notch trowel instead?
Mike and Rob are correct - 1/4 square notch for a 4x4 tile. A 4x4 ceramic is a pretty light tile, if they're not sticking, there's an issue with your technique. You should be using a modified thinset (do NOT use pre-mixed (the stuff in a tub) thinset - it's actually a water-based adhesive and it will NOT last in wet areas ), mixed to the consistencey of peanut butter. A common DIY'er mistake is to mix their mortar too wet. First apply the thinset to the wall with the smooth edge of the trowel and work it back and forth a couple times. This keys the mortar into the backer board (you are applying over cement backer board, right?) for good adhesion to the wall. Then using the notched edge, held at a consistent 45 degree angle to the wall, remove the excess mortar. And work in small sections - with 4x4 tiles, apply the thinset in 2' squares -- otherwise the thinset will set up (and loose adhesion) before you get all the tiles in place. Small batches goes for mixing the thinset, too. Check the label, but most thinsets have a 1-2 hour pot time (how long it can sit in the bucket before it sets up) -- exceed that and the mortar will loose it's adhesion and the tiles won't stick. You can simplify wall tile installation by screwing a starter board to the wall (1x2 or strip of plywood works well), 3-4 courses up from the floor. This will support your first course, and tile spacers will support succesive courses. Then remove the board and finish up the bottom courses.
When I use a trowel I use a V-notched trowel spreasding adhesive in a figure 8 configuration all over the walls, I use a trowel with 5/16th's groove.
Sorry guys wrong. You need to use a 1/4 x 1/4 square notched trowel. You will not get enough coverage on a v notch trowel. Those trowels are for a mastic( non wet area) and mosaic tiles..
it will state clearly on the mastic/mortar package. but normally 1/4 X 1/4, complete coverage and press firmaly. When you put the tile in place, put as close as posible to the desired location and only move slightly to align the tile, press firmly and hold for few seconds and release. if it does no stay, something is wrong, beyond your question.
