I am concerned about the breaking strength of a tile


If the breaking strength of a tile is only 250 pounds, will it support my weight? - Perhaps you can advise me regarding tile strength. I recently have been confined to a wheelchair and need to make accessibility changes to my home. I am thinking of having my bathroom converted to a "wet room" as it seems to be the best choice for access and ease of use.

I was getting myself psyched (despite my circumstances) to start the process of shopping for materials and contractors when I noticed that tile has a weight rating. I am 6'6" and weigh 340lbs. I noticed that tiles seem to be rated at 250lbs. Is there a type of tile that would accommodate someone of my size in a wheelchair?


ANSWER - The breaking strength minimum industry requirement for ceramic tile is a laboratory test of what is mostly an unsupported tile and isn't directly meaningful in terms of determining what kind of dead and live loads it can endure.

More meaningful for your concerns, of how a bonded tile will perform, is the compressive strength physical characteristic of the tile. Most porcelain tiles have over 20,000 pounds per square inch compressive strength capacity or better. The distribution of your weight in a wheel chair should not be a problem for a properly installed tile floor.

You need to be more concerned about how well the tile is installed. If the adjacent edges of the tiles are not even and have a displacement, which is referred to as lippage, then it can be problematic for someone in a wheel chair.

You should download the Free Installation Guidelines for consumers that we offer so you can make sure the tile installer you choose will install your tile correctly.

25 thoughts on “I am concerned about the breaking strength of a tile

  1. Joe McKeever says:

    Ok I have a question. My wife has found an accent tile that is rated for 250lbs “break strength” that we would like to install under our wood stove. The stove itself weighs 400lbs. With your explanation above I would assume it will work??

    • Donato Pompo says:

      Breaking strength is based on subjecting an unsupported tile to a loading stress to determine its resistance to breaking under certain loading conditions.

      If the tile is adhered properly to a stable substrate with full thin-set adhesive contact then it can easily accommodate 400lbs of dead load. The tile will go through much more stress as the stove is moved over the tile floor with some device that will likely apply a much higher concentrated load to the tile depending on the type of equipment used.

      Tile is more likely to crack from reflection cracks continuing up from the substrate or from excessive defection of the substrate that has nothing to od with the breaking strength of the tile.

  2. Richard says:

    I am building a new home, and have to select tile for all of the rooms. One tile that I like is a glazed porcelain 18 x 18 tile. I don’t understand the specs that the builder provided:
    Hardness 8000. Breaking Strength 324, Water absorption 0.3, wet coefficient 0.42, not slip resistant. Tile is shown on the Shaw website. Are these good numbers?

    • Donato Pompo says:

      For a porcelain tile the breaking strength of 324lbf is good. The ANSI A137.1 minimum is 275 lbf. the 0.3% absorption is good; the minimum requirement is 0.5%. A wet DCOF of 0.42 is considered slip resistant for indoor level surfaces that get wet. Of course that doesn’t make the tile slip proof, as not tile is slip proof. Not sure what the 8000 Hardness is. There is a Mohs Hardness test but the values single digits. It can’t be compressive strength as a porcelain tile should be over 20k psi. Maybe it is flexural strength?

    • Donato Pompo says:

      For a porcelain tile with a breaking strength of 275 lbf that is good. The ANSI A137.1 minimum requirement for a porcelain tile is 275 lbf.

  3. Gladys says:

    Is breaking strength of 251-400 good for porcelain tile planks? Also, how soon after installation can I walk on and place fridge on the floor?

    • Donato Pompo says:

      ANSI A137.1 says porcelain tile should have a breaking strength per ASTM C648 of 275lbf average and a minimum of 250 lbf for individual tiles.

      Most thin-set mortars want you to stay off the floor for at least 24 hours or more. Heavy traffic is normally after 7 days. But it depends on the type thin-set mortar you are using. Read the instructions and/or data sheet and it will say what their recommendation.

      Placing a refrigerator requires moving it on a dolly that has various type and size wheels, so all that weight is being transferred to those two wheels surface area that it covers, which is probably about 2 sq. inches. So your floor will take more stress from that than after it is placed in its spot.

      As long as the tile was installed correctly per industry standards and per the installation product manufacturers directions moving the refrigerator should not hurt the floor; unless the tile wasn’t installed properly and it has excessive voids under the tile then it could have a propensity to being damaged in the spots (voids) where it isn’t supported.

  4. mark reeve says:

    hello what is the best strength for a outside porcelain tile please ? option i like is strength of 360lbs is that to low? thank you

    • Donato Pompo says:

      ANSI A137.1 says porcelain tile should have a breaking strength per ASTM C648 of 275lbf average and a minimum of 250 lbf for individual tiles.

      If it is a porcelain tile then it has plenty of strength for any installation application, as long as the tile is installed correctly.

  5. David Meats says:

    We are wanting to install wood look porcelain tile on a cement floor where a grand piano will be rolled from one location to another depending on the type of performance. Will the wood look porcelain tile support the grand piano being rolled across the surface?

    • Donato Pompo says:

      Porcelain tile is a very strong ceramic tile that typically has over 20,000 psi compressive strength. So it would work very well for moving a grand piano.
      Although the tile is only as good as it is installed.

      Make sure the concrete substrate is clean and porous. Make sure the thinset adhesive is applied correctly.

      For tile floors that will have heavy traffic or equipment the thinset adhesive contact should make substantially 95% contact between the tile and the concrete floor. It should not have any voids under the tile at the tile corners or edges. Floor tiles should never be spot bonded, which is when the installer only applies dabs of thinset leaving a lot of voids.

      If there are voids under the tile and those spots are subjected to a heavy load or a heavy object then the tile can crush or crack in those spots.

      Since you will be rolling a piano over the tile, make sure the tile is installed with no more than 1/32″ of tile lippage where one edge adjacent to another tile edge is higher or lower than the other. You should have at least 1/8″ wide grout joint.

      • David Meats says:

        Sir, thank you very much for your prompt reply. It is difficult to find technical information online from someone that actually has experience working with porcelain tiles.
        So thank you very much. Have a great day and best wishes for all that you do.

  6. Narine says:

    We are wanting to install 10.3 mm thick Porcelain tile, 24″x48″ in size. The home was built 8 years ago in middle TN, It is on a sloped land and elevated with concrete blocks in the crawl space. We feel the floor curve or bow a bit as someone else walks on it. Will the tile crack? is there anything we can do to help prevent cracks? will installing tile underlayment help? we plan to do 1000 sq ft space, the home is 2 story and 2900 sq ft total. Thank you for all the help

    • Donato Pompo says:

      First of all you need to make sure your subfloor doesn’t have too much deflection as that might be why it is bowed. You can add bracing between the floor joists to stiffen it up to maybe help overcome the bow, but also to take the added weight of a mortar bed.

      One of the reasons you install a mortar bed is to make sure your floor is level or sloped as desired. Instead of a mortar bed you might consider installation a cementitious self-leveling underlayment to make the floor level for the interior application.

      As long as you don’t have too much deflection and the mortar bed or underlayment is installed correctly, and the tile is installed correctly with movement joints at the perimeters and throughout the floor then there is no reason why your tile should crack.

      We have a free download for homeowners that provides guidelines and suggestions on what to do to achieve a successful installation at https://ctasc.com/expert-answers-overview/.

    • Donato Pompo says:

      The standard 275 psi breaking strength is plenty if the tile is installed correctly. Porcelain tiles are installed in car dealership service areas all the time. They need to be slip resistant, stain resistant, and installed with full thinset contact under the tile. Of course the garage concrete substrate has to be properly grind and prepared to get a good bond using a good polymer modified thinset mortar.

  7. John Caldwell says:

    Thanks for the reply. Follow up question is about the breaking strength listed on some tiles. They’re not listed in psi. It’s listed as: S, followed by the greater than or equal symbol, 1300 or 2000n. No response from the company. Any help appreciated.

    • Donato Pompo says:

      Those units and values don’t make sense in terms of breaking strength. The English units is PSI (pounds per square inch). N normally stands for newtons which is a force. Normally it would be N/mm to be able to convert to PSI. But there are 145 psi per 1 n/mm, so based on the numbers you show that doesn’t make sense. I don’t know what S stands for.

      • John Caldwell says:

        Thanks again for getting back. They do list N/mm2, calling it “Modulus of Rupture”. It’s: R greater than or equal to 40 N/mm2. Per your 145 psi per, that would put it at 5,800 psi? Don’t understand the 2 after N/mm. Squared?

        • Donato Pompo says:

          The means the square of the number meaning multiplying the number by itself.

          The modulus of rupture is the quantity obtained by dividing the calculated breaking strength by the square of the minimum thickness along a broken tile edge.

          So if you multiply the modulus of rupture by the thickness of the tile it will be a smaller number. This suggest that the tile has a high breaking strength.

  8. David Farrell says:

    I am wanting to put a black tile in a bathroom. I see quite a few hexagon black I like but then found a square 12″ x 12″ porcelin tile I thought would be easier for my beginner self. The tile says it has a PEi of 3, It is only 1/4″ listed in the spec and only has a breaking strength of 120 pounds. It is listed as a wall and floor tile both. I put a pair of calipers on my currrent wood sheeting subfloor and it show .6″ (6/10 of an inch. I was going to add another layer of 3/8″ or 11/32″ sheeting followed by 1/4″ Hardie backer board. I am only doing the floor in tile. My quwation is, I thought in order forma tile to meet a PEI rating of 3 and a floor tile, doesn’t it need to have a breaking strength greater than 120 lbs? Or will this tile be ok. I dont want anything breaking or cracking.

    • Donato Pompo says:

      Per ANSI A137.1 for pressed floor tiles the minimum average breaking strength requirement is 250 lbf (1.11kN) or for ceramic porcelain tile the requirement is 275 lbf (1.22kN).

      It is good to build up the floor, but depending on the spacing and types of floor joists that will determine whether it meets the maximum allowable deflection for ceramic tile of L/360. Also the wood sheeting and the backer board has to be installed in a staggered pattern within each layer and over the underlying layers per the manufacturer’s directions and industry standards.

  9. rajendran t says:

    we are using 3 mm thick ceramic tile for external dry cladding work. imported from spain. kindly advice what is the minimum breaking strength amd mor required.

    • Donato Pompo says:

      Per ANSI A137.3-2022, for Gauged Porcelain Tiles and Tile Panels/Slams with a nominal thickness 3.5 to 4.9 mm (0.14 to 0.19 inch):
      Breaking Strength per ASTM C1505 test protocol minimum is 85 lbf (0.38kN)
      Modulus of Rupture per ASTM C1505 test protocol minimum is 6,000 psi (41 MPa).

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