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How much should Grout Joint Widths vary in size in a Tile Installation?
QUESTION
Hello, My contractor installed 2' x 2' porcelain rectified tile to my kitchen. I wanted 1/16" grout lines but was told that the recommended lines should be 1/8" so I agreed to that. The area is 350 sf. The installer use spacers. The tile is now installed and a few of the tile are actually 1/8", most are larger than that and about 20% of the floor grout lines actually measure 1/4". My question is, is it reasonable for the grout lines to vary to that degree.ANSWER
ANSWER - The tile industry standards say that grout joints should never be less than 1/16" wide, and tiles should never be butted up to each other. It is recommended that the grout joints be a minimum of 1/8" or wider depending on the sizing tolerance of the tile being installed.What dictates what the grout joint width should be depends on how consistent is the tile sizing or how much variation there is in sizing. The standards state that the grout joint width shall be at least three times the actual variation of facial dimensions of the tile supplied. The standards for calibrated porcelain tiles allow for about 1/16" size variation, so the grout joint width should be at least 3/16". Rectified porcelain tiles allow for about 1/32" size variation, so the grout joint width should be at least 3/32".
The standards state that the nominal centerline of all grout joints shall be straight with due allowances for hand-molded or rustic tiles. There is some language being considered to add to the ANSI standards that say that the grout joint widths shall not vary more than +/- 25% of the intended grout joint width; other than for hand-molded or rustic tiles.
So if the intent was to have a 3/16" wide grout joint, then plus or minus 1/16" (1/8" to 1/4") could be reasonable depending on the type tile that was being installed.
7 thoughts on “How much should Grout Joint Widths vary in size in a Tile Installation?”
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Hi Donato,
What’s the industry standard re: grout joint decision making process between the home owner and a hired professional tiler? Is it the professional tiler’s responsibility to facilitate grout joint discussion with the home owner prior to tile installation so the decision on the grout joint spacing is made with mutual understanding for both parties ? Also, is it the industry standard that it is the professional tiler’s responsibility to follow the tile’s installation guide? Thank you!
Normally the tile installer will recommend a minimum grout joint width as it can affect how he can install the tile depending the sizing tolerances of the tile being installed. It can also affect the layout. Sometimes you can make the grout joint a little smaller or a little larger in order to avoid having to make tile cuts. Sometimes the architect or home owner will insist on a certain size at their own risk.
The installer should be aware of what the minimum width grout joint is for the tile. For natural stone or ceramic tile the recommended minimum width grout joint is 1/8″, but they say never less than 1/16″. The standards say it is never recommended to butt tiles together as it can lead to problems, and it limits the installers ability to adjust the tile installation to help compensation for the size variations of the tile.
We had a tile floor installed in our kitchen and the grout spacing varies from 0″ (tiles are butted together) to 3/16″. This variation is spread across the entire floor. The installer is claiming that there is no problem although the variance is easily visible. Is there any sort of standard we can refer to when making our case about repairing the floor?
Floor tiles should never be butted together. Industry standards recommends at least 1/8″ wide, but never less than 1/6″ wide.
Normally the allowable tolerance for the grout joint width variation is +/- 25%.
Per ANSI A108.02-4.5 – 2023 Grout Joint width: To accommodate the range in facial dimensions of the tile supplied for a specific project, the actual grout joint size may, of necessity, vary from the grout joint sized specified. The actual grout joint size shall be at least three times the actual variation of facial dimensions of the tile supplied. Example: for tile having a total variation of 1/16 in. (2 mm) in facial dimensions, a minimum of 3/16 in. (5 mm) grout joint shall be used. NOTE: Nominal centerline of all grout joints shall be straight with due allowances for natural, hand-molded, or rustic tiles.
Thank you very much Donato. One more question: What is the possible issue with having tiles butted together (zero grout)?
Tiles expand and contract as they are subjected to temperature fluctuations and moisture fluctuations. If the tiles are butted together, then as they expand it puts a shear load on the adjacent tiles that can cause chipping to the edge of the tiles and/or cause the tile to debond.
Thank you very much for your help and expertise!