A friend of mine owns a 1950s ranch. He put a new kitchen in the last six months, with 12″ tile on the floor. The other day he showed me two, 10 foot, hairline cracks in the middle of the tiles running the full length of the kitchen (One crack is about 3′ from the exterior wall, the other about 6′).
Investigating this in the basement, the cracks seem to be running on or very close to the joists underneath. There doesn’t seem to be any type of settling in the foundation. And the framing seems to be in good shape. The cracks are located above the ducting, if that matters.
I worry that the tile cracks are a very sensitive sign of a much greater problem: the house is sinking. We live in SW PA, where many of the houses have old, inactive and active coal mines underneath.
My suggestion was to get a structural engineer in to take a look — if nothing else, it will give him some peace of mind. But, if it’s not a structural/mine subsidence problem, I’ve never seen anything like that. Any suggestions?
Replies
The first suggestion would be to check the size and span of the joists to see if they are undersized. If he installed underlayment, those cracks could be turning up on those lines.
A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
If I underand it the cracks run the leght of the joist.Seems to me that joist problems would cause crack perpendicular to the joist.I am not that much of a tile expert, but would suspect a problem with the substrate. CBU screwed to the joit, no thinset under the CBU, too thin subfloor..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
The long straight crack suggests to me a lot of movement and some even sheet line. I've seen this on a couple occasions where the underlay was ply rather than durock. Every 4', across the kitchen. No other cracks but those straight lines.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
More likely the floor simply has too much deflection for 12x12 tiles. Go to JohnBridge.com for a link to their 'deflecto meter' (or something like that) that easily figures this out.
Bill
If you have significant subsidence problems you'll see other signs -- (large) cracks in the foundation and basement floor, cracks in the plaster above windows, etc. Hairline cracks in wide tile (or even above windows or in concrete work), while not great esthetically, are probably not indicative of a serious problem.
Hardiebacker underlayment comes in 3 ft widths. Is the crack through the tile or the grout?
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What you describe is indicative of poor prep - too much deflection in the floor struture for these tiles. The previous flooring was probbaly a vinyl or resiliant material that absorbed the movement while these do not. Ceramic tile requires floors with far less deflecction.
So, " the framing seems to be in good shape." means little. good shape for what?
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