Most tile installations require a 3/16-inch layer of mortar beneath the tile. A mortar layer 3/16 an inch thick is accomplished by spreading mortar with a 3/8-inch by 3/8-inch square-notched trowel. This thickness is ideal for most tile installations. However, sometimes a thicker layer of mortar is required. A common tile trowel size for these installations is the 1/4-inch by 1/4-inch square-toothed trowel. This trowel will leave a layer of thinset 1/8 of an inch thick beneath your tiles.
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How Do You Calculate Thinset Thickness?
The thickness of your thinset layer will depend on the type of trowel you use to spread it. If you use a trowel with square teeth that are evenly spaced, the resulting thinset layer will be one-half of the tooth depth. This means that a 3/8 X 3/8” square notch trowel spreads thinset in ridges 3/8-inch high and 3/8-inch apart. When a tile is pressed to this thinset, it spreads to fill the spaces between the ridges, resulting in a thinset layer 3/16ths of an inch thick.
- A square-notched trowel with tooth spacing that is the same as the tooth depth creates a thinset layer that is one-half the tooth depth.
- A 3/8 X 3/8” square notch trowel, like this one, creates a 3/16” thick layer of thinset.
- This 1/4 X 1/4” trowel will create a thinset layer 1/8-inch thick.
- U-shaped trowels leave a thinset layer one-third of the tooth depth.
If you are using a trowel with U-shaped teeth, to install 12×12 ceramic tiles, for example, it will create a thinset layer one-third as thick as the tooth depth. So, this thinset trowel with 3/8-inch U-shaped teeth will create a layer of thinset 1/8-inch thick. These simple rules will help you calculate thinset thickness for any tile job.
How to Use Cardboard to Mock Thinset Thickness
A great trick for seeing how high your tile floor will be after it is installed on top of the thinset is to cut off the side of a box of tiles and place the cardboard beneath the tiles. Most shipping boxes are made of cardboard 3/16-inch thick, which is also the most common thinset thickness for tile installation. By placing tiles on top of the cardboard, you’ll get an excellent idea of how much height the thinset will add to your tile installation.
- Tile shipping boxes are commonly 3/16-inch thick.
- Most tile installations require a 3/16-inch layer of thinset.
- Cut off a portion of the tile box and lay tiles on top of it to estimate how high the tile will be when laid on top of thinset.
- Use the cardboard-beneath-tile trick to see if tile will fit under baseboards and trim prior to beginning your install.
One of the best ways to use the cardboard trick is in areas where tile is meant to be installed under existing trim or cabinets. Slide the cardboard into place under the trim, then try to slide the tile into place on top of it. If the tile doesn’t fit on top of the cardboard, it won’t fit once you’ve spread your thinset.
Can You Use Too Much Thinset on Tile?
An excess of thinset can cause an uneven surface, ooze between tiles, and form a poor bond between tiles and your substrate. Use just enough thinset mortar to form a solid bond between the back of the tile and the surface beneath. In most installations, a layer of thinset 3/16 to 1/8-inch thick is sufficient.
- Too much thinset creates a mess and inhibits proper bonding between the tile and the substrate.
- For most tiles, apply a layer of thinset 3/16–1/8-inch thick.
- Do not attempt to use more thinset in order to level a surface.
Thinset mortar is not designed to be used to level surfaces before installing ceramic tiles. It is meant to form a thin layer that follows the contours of the surface. Using thinset to fill gaps results in cracked thinset and poor tile adhesion. Correct an uneven surface with backer board or other patching materials before tiling.
What Happens if Your Thinset is Too Thick?
If your thinset application is too thick, you will often have difficulty leveling your tiles as you install them. It is also common to see thinset squeeze out from under the tile into the gaps between the tiles. This is a problem because it doesn’t allow for proper grouting. If you’ve used too much thinset, you’ll know as soon as you begin placing tiles. The result will be an uneven, messy tile job.
- Uneven, slanted tiles are a sign of too much thinset.
- If you have too much thinset, it will often squeeze into the gaps between tiles, making grouting difficult.
- If you see these signs, remove the tiles and thinset before the mortar dries. Then, spread a thinner layer of thinset.
- Experiment with different trowel sizes if you see the signs of too much thinset mortar.
If you see the signs of too much thinset mortar during installation, immediately remove the tiles you installed. Then, scrape the thinset off the floor or backer board, as well as the tiles themselves. Finally, use a trowel with smaller notches to spread new thinset and install again.
How Much Thickness Does Tile Add to a Floor?
Tile thickness depends on the type of tile used. Porcelain tile tends to be on the thicker end of the spectrum, with typical thicknesses in the range of 1/4–3/4 of an inch. Ceramic tiles are usually thinner, ranging between 1/4 and 3/8 of an inch.
- Tile thickness depends on material, style, and the individual tile.
- Porcelain tiles range from 1/4” to 3/4” thick.
- Ceramic tile tends to be between 1/4” and 3/8” thick.
- Other types of tile, such as glass tiles, can be up to 1/2” thick.
Glass tile and mosaic tile also have varying thicknesses, typically ranging between 1/8-inch and 1/2-inch. When planning your tile install, take into account the unique thickness of your tile, as well as the thickness of the mortar. A thicker tile will add more significant height during installation than the layer of thinset.
How Much Thickness Should You Allow for Thinset when Tiling?
Plan for a layer of thinset 3/16-inch to 1/8-inch thick beneath your tile. A 3/16-inch layer of thinset will be enough for tiles with a smooth back to bond the tile to the floor or backer board. For natural tiles with an uneven surface on the back, you may need to spread a 1/8-inch layer of thinset during installation. Thinset works best when it is a relatively thin layer of material spread across a smooth surface or backer board. Do not plan to use additional thinset to fill holes or low spots. Using too much thinset can result in a poor tile installation.
