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Last year we had ceramic tile installed in our newly purchased house
in Tucson which was about 12 years old. In typical Tucson fashion
it is a house on a concrete slab and at the time of construction the
use of rebar in the floor was considered exotic — thus the slab
has a number of cracks, some small, but two larger ones (about 1/2″
gap) in the living and dining rooms.
When our installer laid the floor he followed the standard procedure
(for here) of putting down a roofing-felt-like “slip sheet” over the
cracked areas and then proceeded to lay the tile in a normal fashion
This was done in late January and early February. As we entered
the summer and temperatures soared (yuck!) we noticed that the
tile was detaching from the floor and a fair area of the living and dining
rooms actually bowed up a visible amount. Once temperatures finally
went down (in “winter”), the tile settled back down though obviously
it’s still detached from the floor underneath as witnessed by a ‘hollow’
sound if you rap on the tiles.
Our theory is that in the heat of summer that the slab moves some,
closing the gap of the cracks and that this has popped the tile.
Our tile installer is going to return and relay the floor. This time
he plans to use some more exotic membrane slip sheet that glues to
the floor and use a special thinset with additives (?).
Our concern is that even with this treatment, movement of the crack
through the seasons will cause the floor to have the same problem.
What can we do to solve this problem once and for all? The only idea
that we’ve come up with so far is to fill the major cracks with
something — epoxy (?), mortar (?), portland cement (?), whatever,
that would prohibit the crack from closing in the summer. Will
this work? Is there something better to be done?
Any advice will be appreciated.
regards,
Margaret
Replies
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I would be concerned about filling the crack with anything sufficient to keep the crackfrom closing again. The concrete is still going to expand, no matter what you do, and if it can't fill up that crack, it will move elsewhere.
It would be a shame to have to tear up the whole slab and re-do it just because of a crack and a few tiles.
*Margaret,Try posting this in the discussion forum at http://www.floorsearch.com. There are a lot of installers over there and one of them may have a good solution to your problem.As for the cracks, it is possible to epoxy in some wire "staples" across the crack when it is at its smallest separation. If the crack runs pretty straight across the room it's also possible to saw cut an expansion joint through the slab. There are a number of commercial products for this use that will work with the tile and be somewhat unobtrusive. The floor would then move along the joint and the remainder of the crack could be epoxied.Let us know how it turns out.Eric
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Not to badmouth your installer, but I would have used the "exotic slipsheet" and the thinset additive the first time around. The membrane I use is called "Nobleseal", it's a rubbery type of plastic with hairy fibres embedded on both sides, to provide adhesion to the thinset. Be sure to extend the membrane at least three tile widths on each side of the crack. I would also use an additive such as Hydroment brand "Elastoment" which is an additive designed for attaching tile to "cutback" the residue left on concrete from carpet or vinyl tile adhesisve.
This additive makes the thinset somewhat flexible. Use the additive in your grout mix also. I wouldn't worry about filling the cracks unless they're huge I did a commercial job about five years ago with this technique,where we had numerous cracks up to 1/8", and I haven't had a callback yet so I assume it's working. I live in southern Idaho where the temperature can range from 20 below to 100+. Good Luck...
Freehand
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Advice - find out ...
How thick is your concrete slab?
What strength of concrete?
Not rebar - was temperature steel (welded wire mesh) used?
What thickness of drainage fill (crushed stone)?
How effectively was the subgrade compacted?
Vapor barrier?
What went wrong?
1/2" cracks in a concrete slab are indicative of much more than a tile problem - find out what the serious problems are and fix them before anything else! If they run down the center of the slab in each room it's usually a compaction / settling problem or, failure to use or overlap the welded wire mesh.
Jeff Clarke
*The stuff Freehand is referring to is Nobleseal TS..a great product. Another crack isolation membrane that I have not used but have heard good things about is one made by Schluter(sp).Good Luck...Dave
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Last year we had ceramic tile installed in our newly purchased house
in Tucson which was about 12 years old. In typical Tucson fashion
it is a house on a concrete slab and at the time of construction the
use of rebar in the floor was considered exotic -- thus the slab
has a number of cracks, some small, but two larger ones (about 1/2"
gap) in the living and dining rooms.
When our installer laid the floor he followed the standard procedure
(for here) of putting down a roofing-felt-like "slip sheet" over the
cracked areas and then proceeded to lay the tile in a normal fashion
This was done in late January and early February. As we entered
the summer and temperatures soared (yuck!) we noticed that the
tile was detaching from the floor and a fair area of the living and dining
rooms actually bowed up a visible amount. Once temperatures finally
went down (in "winter"), the tile settled back down though obviously
it's still detached from the floor underneath as witnessed by a 'hollow'
sound if you rap on the tiles.
Our theory is that in the heat of summer that the slab moves some,
closing the gap of the cracks and that this has popped the tile.
Our tile installer is going to return and relay the floor. This time
he plans to use some more exotic membrane slip sheet that glues to
the floor and use a special thinset with additives (?).
Our concern is that even with this treatment, movement of the crack
through the seasons will cause the floor to have the same problem.
What can we do to solve this problem once and for all? The only idea
that we've come up with so far is to fill the major cracks with
something -- epoxy (?), mortar (?), portland cement (?), whatever,
that would prohibit the crack from closing in the summer. Will
this work? Is there something better to be done?
Any advice will be appreciated.
regards,
Margaret