One of our tiles has cracked across a 3rd of its width, can you advise?
Asked by... Martin Swaine from Bristol

The Question

Our builder has laid Heritage Grey Antiqued Flagstones on to two newly constructed solid floors. One of the flags is cracked across a third of its width. He is denying any responsibility for causing it and says that as the material is natural, it can crack of its own accord. Could you give me your response please?
 

The Answer

Hello Martin

That's a very interesting question and in honesty there's not a clear cut answer, rather it raises a few questions but if you could help us further we will come right back to you. Could you let us know the following;

- The newly constructed floors, what are these constructed of?
- Concrete/screed - Was the substrate completely dry before tiling commenced? What type of screed? Was it moisture tested before installation began?
- Wood – Was the floor adequately braced to minimise flex? If you could give us some more information about the construction, what thickness, type of wood etc.?
- Is there an underfloor heating system installed? If so what type, electric or wet piped? Was this commissioned before tiling began?
- Does the tiling run throughout both rooms continuously? Where appropriate, are there expansion joints installed?
- What type and brand of adhesive was used to install the tiles?
- How was the adhesive applied to the substrate?
- Is the tile cracked or is it a vein within the tile? If it is definitely a crack, when was the crack first noticed?

It would help us to help you if you could you send us some photographs of the tile please to becky@mrs-stone-store.com. The answers to these questions and photographs will shed a little more light on the installation itself and may help us get to the bottom of the matter for you but here's a couple of things to consider.

It is important to note that limestone will exhibit naturally occurring veins within the stone which customers can mistake for a crack. Veins are basically visible lines of varying direction, depths/widths and sometimes colours which indicate a pathway of hot, mineral-rich fluids that were at one point forced through the limestone during its creation. When the fluids cool, they leave behind mineral deposits which form the vein. These veins can occur across part of but not necessarily across all of a tile but in all cases, these are present in the tile before installation begins but it's important to note that veins are not weaknesses in the tile.

As mentioned, the answers to the questions above will help us to help you but in general, if a tile is fixed to a surface which is structurally sound and sufficiently dry, has minimal flex, using the correct adhesive which is applied to the surface in the correct manner, and the fixing follows all current guidelines of BS 5385, a tile shouldn't crack post installation.

If you consider, a tile placed on a completely flat, firm base will not have anywhere to go when pressure is applied to the surface and will therefore not break however if there were a void or movement underneath the tile for whatever reason, the potential for cracking when force was applied is a possibility.

If you would like to send over some photos and answers to the questions above, we can have a look and get back to you Martin.

- Wednesday 3rd February 2016
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