Interesting crack pattern

[John Kogel]

Kitchen floor tiles have perpendicular cracks the full length and width of the room. The one crack is 5 feet out from the cabinets. The subfloor is OSB on 2 x10 joists, 16"centers.

From the height of the tiles, we think they laid down tileboard and didn't fasten it to the subfloor properly. Besides staggering the joint, what should these amateur tile setters have done to prevent this?

[Gunnar Alquist]

I seem to recall that ceramic floor tile needs a pretty thick substrate. Can't remember if it is 1.25" or 1.5". I would guess flexing in floor system caused those cracks.

[Darrel Hood]

I am embarrassed to admit that I did what this appears to be on a rental mobile home a few years ago. I was too far from town to buy longer screws so I used what I had in my truck. They were too short and the result was heaving subfloor. This appears to be what the photo shows.

[Garry Sorrells]

If they laid tile board and did not bed it and just screwed it down there may have been a stress point created. After time the board screws, under pressure eat their way through from the tension an allow the board to move.

If the board was not bedded and nails were used then same problem but occurs faster.

If the board is not staggered when laid, another possible cause even if bedded.

Laid cement board running with joist instead of at right angle.

If OSB sub floor not staggered it will affect the tile no mater how it was laid.

If 1/4" in stead of 1/2" cement board was used even with bedding another possible cause.

If the tile was not laid with correct trowel notching size.

If they laid bed mortar on half of room and allowed it to dry then started with wet for rest of room may be a possible cause but not to likely.

They may have laid plywood over OSB and then used mastic to set tile. Where plywood was not screwed through the OSB into the joist but just to the OSB. Or the plywood was not thick enough to create a rigid floor.

Then there is a potential settlement issue somewhere stressing that joist.

My bet would be on lack of staggering on the sub floor or the underlayment of the tile. Two intersecting cracks at right angle is the reasoning.
- - - Updated - - -

If they laid tile board and did not bed it and just screwed it down there may have been a stress point created. After time the board screws, under pressure eat their way through from the tension an allow the board to move.

If the board was not bedded and nails were used then same problem but occurs faster.

If the board is not staggered when laid, another possible cause even if bedded.

If OSB sub floor not staggered it will affect the tile no mater how it was laid.

If 1/4" in stead of 1/2" cement board was used even with bedding another possible cause.

If the tile was not laid with correct trowel notching size.

If they laid bed mortar on half of room and allowed it to dry then started with wet for rest of room may be a possible cause but not to likely.

They may have laid plywood over OSB and then used mastic to set tile. Where plywood was not screwed through the OSB into the joist but just to the OSB. Or the plywood was not thick enough to create a rigid floor.

Then there is a potential settlement issue somewhere stressing that joist.

What should they have done?
Taken more time to understand all of the factors that have to be accounted for and technical aspects involved in installing tile. Probably not relying o the DIY shows on TV for their technical assistance.

[Billy Stephens]

what should these amateur tile setters have done to prevent this?

Called the Tile Layers.;)

[John Kogel]

They may have laid plywood over OSB and then used mastic to set tile. Where plywood was not screwed through the OSB into the joist but just to the OSB. Or the plywood was not thick enough to create a rigid floor.

Then there is a potential settlement issue somewhere stressing that joist.

What should they have done?
Taken more time to understand all of the factors that have to be accounted for and technical aspects involved in installing tile. Probably not relying o the DIY shows on TV for their technical assistance.Thanks Garry and Darryl. The lack of staggered joint says "amateur" pretty clearly, allright. The tiles in the bathroom are laid directly on the OSB subfloor and there are no cracks. So the evidence is underlayment laid wrong. Thanks, Garry, for all the ways they could have screwed up. Looks like you've seen them all.


Called the Tile Layers.;)Elvis is alive, laying tiles down in Memphis!

[Billy Stephens]

Elvis is alive, laying tiles down in Memphis!

Elvis Lays PIPE!! :)

[Ted Menelly]

2x10 16 inches on center matters not. Ow much deflection does the floor have. What is the span of the 2x10s.

And what someone else said

"What should they have done?
Taken more time to understand all of the factors that have to be accounted for and technical aspects involved in installing tile. Probably not relying o the DIY shows on TV for their technical assistance."

This clearly sounds like the 2x10s span is much too great and base for the tile not applied properly.

[John Kogel]

Ted the span is no more than 12 feet, although I did not measure, belly down crawlspace.