# Cracking Grout Between Shower Tiles



## average (May 3, 2007)

I recently replaced a small section of tiles in my shower because the grout was cracking and beginning to separate from the tile. It was easier to just rip up the tiles and relay them, rather than delicately removing the grout. I re-grouted the section of tiles, using Premixed Adhesive & Grout (unsanded) from Lowe's. The grout job looked good after finishing it, but the next morning the grout is already beginning to crack! What could be causing it? Does the premixed grout from Lowe's just suck? Are my tiles spaced too far apart? I appreciate any suggestions.


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## ron schenker (Jan 15, 2006)

Never use premixed adhesive (mastic) in a wet area even though some of the labels say it's alright. Use fortified thinset mortar (white if it's a light colored tile) and never use premixed grout (it's useless). Mix the grout yourself and you shouldn't have the cracking problem anymore. What kind of substrate (backerboard) was under the tiles?


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## average (May 3, 2007)

Well, er...the tiles are actually around a glass block window. I just mortared the tiles to the wood frame of the window, and the tiles that trim the window are actually glued onto the cultured marble shower walls with liquid nails. I imagine that using liquid nails is probably a bad idea as well. What is the suggested way of setting tile against cultured marble?


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## ron schenker (Jan 15, 2006)

average said:


> Well, er...the tiles are actually around a glass block window. I just mortared the tiles to the wood frame of the window, and the tiles that trim the window are actually glued onto the cultured marble shower walls with liquid nails. I imagine that using liquid nails is probably a bad idea as well. What is the suggested way of setting tile against cultured marble?


Well you lost me now. I think we could use a better picture


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## average (May 3, 2007)

Sorry I wasn't clear before. Here are some more pictures. The tiles that are on the actual shower walls are glued on with liquid nails. The tiles that are on the actual sill of the window are glued down against the wooden frame with thinset mortar.


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## Tscarborough (Mar 31, 2006)

I would use a sanded elastomeric caulk on all of those joints.


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## ron schenker (Jan 15, 2006)

I've never heard of using liquid nails to lay tiles in a shower. Keep us posted as to whether or not they stay up there. I have a feeling they'll come loose pretty soon, but I've been wrong a couple of times before.


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## MikeF (Sep 28, 2006)

Grout cracks because the tiles are moving, that's the only reason it cracks.

Tiles only move because whatever they are attached to is moving.

A tile job is only as good as what it is layed upon.

Solve the movement of what the tiles are layed on and the grout will stop cracking.



> I just mortared the tiles to the wood frame of the window,


Anything wood expands and contracts, which might be a really good place to look for your problem. Tile should rarely if ever be connected to anything wood.


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## Tscarborough (Mar 31, 2006)

They will also crack if the grout is too wet when applied, or worked with too much water, as well as from too wide vs depth joints.


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## J187 (May 19, 2006)

I think the unorthodox substrate here can't be a coincidence. I feel like solving that will solve the cracking.


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