Crack in tile floor?

Did an inspection this morning on a 4 yr old home. The house is built on a slab and is all brick. No cracks on the interior walls. The only crack outside is a step crack above a double garage door. The question is about a crack in the kitchen tile floor. The crack went through about 6 tiles through the middle. With no other cracks on the interior walls would this be caused by some major defect in the slab?

I am working on getting pics uploaded, I am have some trouble.

Here they are

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This is most likely caused by a wild un-controled crack in the slab and would not have much of a structural concern.
I have seen that occur in new slabs one year latter.

Once the shrinkage has occurred most likely one could make the necessary repairs and would possibly not happen again.

Note what you observed and recommend monitoring or further eval.

Hope this helps.

Marcel :slight_smile:

Could be improper thin set application in this area.

Raymond; It is conceivable that an existing crack was in movement after the tile was done and was existing before the tile was done.

In most cases the tile setters would notice these potential problem cracks and use this over the cracks.
Thin set adhesives are usually installed with 3/8" notch trowels.
Pretty hard to screw it up.

Many specifiers call for anti-fracture membranes today. Anti-fracture membranes are designed to protect ceramic tile floors from cracking. The rubberized asphalt membranes are installed over floor substrates (concrete or wood). A latex modified thinset mortar bed is installed over the anti-fracture membrane, and finally ceramic tile is installed.

Anti-fracture membranes protect ceramic tile by providing a stress absorbing layer between the substrate and the tile. If the concrete substrate underneath cracks, the stress of the crack is not transferred up to the brittle ceramic tile. The stress is absorbed by the rubbery nature of the rubberized asphalt.
Tileguard is Polyguard’s anti-fracture membrane. Tileguard is a 40 mil “peel and stick” product, with a fabric on top, to which the thinset mortar bed adheres.
You might also be interested to know that before anti-fracture membranes were used for ceramic floors, they were used for many years to reduce cracking in highways. Additionally, the same anti-fracture stress absorbing properties are used in Polyguard’s Underseal™. Underseal™ Underslab Waterproofing Geomembrane, a much heavier duty version of Tileguard, protects concrete slabs from cracking, and provides a permanent barrier against moisture, toxins, gases, and insects.

[size=5][size=4]Tileguard™ Anti-fracture Membrane [/size][/size]


Click image to view full size](

Tileguard anti-fracture membrane is a 40 mil stress absorbing membrane which protects overlying ceramic tile from cracking. Cracks in the substrate (concrete or other) generate a cracking force upwards, but the cracking energy is absorbed by the elastomeric rubberized asphalt in Tileguard.
***Tileguard’s ***fabric backing bonds to latex modified thinset.

Marcel :slight_smile: :slight_smile:


That is what I originally thought. I figure it happened pretty soon after construction. With no other visible signs of a structural defect I was not too concerned.

Its also conceivable there is a void in this area. Never assume anything.

If such a void would have created the cracking, a simple tapping of the area in question would have given it away.
That would have confirmed that possibility.

Marcel :slight_smile: :slight_smile:

Strange the cracks are not in every tile only six. Doesn’t look like the cause is necessarily a crack in the slab. The crack takes an irregular path through one tile in front of the fridge.

Still think its poor installation, dirt under tile, floor not preped properly? It only takes a bit of dirt under the tile or in the thin set to cause a crack.

Raymond, I will show you a picture of a simple crack own my own job that occurred two months after installation, and it was not dirt.

I will take a picture on Monday.

With tile on slabs, one is at the mercy of the concrete slab, especially control joints, compression strengths, moisture contents, quality of the finish, and installation procedures.

I have had six tile crack on a floor area of 8000 s.f. now that is not bad.

Only through designed control joints in slab can one minimize the amount of slab movement being imaged through tile work surface.

Marcel :slight_smile: :slight_smile: :wink:


You are assuming its due to sub floor crack. You are speculating as much as I am. Without being party to the installation its an assumption as much as my guesses to the cause are assumptions. You don’t know the quality of tiles, or the thin set, or even if they were installed per manufactures requirements or whether someone dragged the stove or refrigerator accross the tiles. I have seen tiles crack on concrete floors that were due to poor installation or cheap tiles, wall tiles as opposed to floor tiles.

In that regard it would be wrong in my opinion to tell the homeowner its due to subfloor crack as the only cause.

I guess what I am trying to impart is that it could be due to a combination of problems not necessarily on a sub floor crack alone.


If that is the case, how would you call it and not speculate on your inspection prognosis?

Anything that you write on your report would it not be the same as what your saying?

I am just trying to explain what actually happens in the real world of building and installing such products and facts of everyday dealings with such occurrences.

I do not ever assumme anything, that would be detremental to the position that I have.

I deal with facts, remedial solutions, and prevention of problems.

Marcel :slight_smile: :wink:

We don’t know the full particulars of this particular instance, only what we have been told.

This article deals with a variety of factors, from contaminants, to cracks to improper prep, et ceteras.

Here is another interesting site that may be of interest.

:wink: I know all about it Raymond, I do it every day. ha. ha.

Mud set, thin set, tub enclosures, shower pans, all part of every job I do and if it fails, I am the first one to get called.

Thanks for the information, for I think it will help some.

Marcel :slight_smile:

Here is a crack that was caused by a slight movement of the concrete slab below.
Wild crack that originated from the corner of the doorway where the foundation was bonded out, created a corner and took off. It will be monitored and repaired before the 1 year warranty runs out.
Sometimes, one has no control as to where a concrete slab will relieve itself.

Marcel :slight_smile:

Crack looks very familiar.