tiling over expansion joints [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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scott anthony
01-28-2003, 06:48 PM
Hey guys me again sorry just can't stop learning.
When tiling a large floor Iv noticed cut lines in the concrete, some look done better than others. I guess this is an expansion joint, right?
I was taught to just thin set fill these joints as I go. This does not sound right.
We have used isolation membrane strips on large settlement cracks. We are talking settled remodels. I have heard that some installers or the good ones will never do floor without a underlayment of some sort.
While I'm talking about underlayment "on slabs," what do some of you pros recommend. I never get the chance to experience this application. Well, just once, we were forced.

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scott anthony
01-28-2003, 07:12 PM
I just watched the ditra underlayment video. looks like an easy application.

John Bridge
01-28-2003, 07:23 PM
Hi Scott,

Saw cuts are not expansion joints. They are similar to control joints. If the concrete is going to crack (and it usually does), the designer/engineer/architect wants it to crack there. Going over them is a matter of choice. I've done it on commercial jobs after I've explained the ramifications to the powers that be. Certainly, putting a membrane down would be a plus.

Dave Gobis
01-28-2003, 07:45 PM
They call them control joints because in theory, they control the cracking. Tile over them and it will probably crack too.

scott anthony
01-29-2003, 05:51 AM
So I take it that the "best" way is to use some sort of membrane over these joints.
Thanks Scott

01-29-2003, 07:07 AM
Scott, see if you can get your hands on some Flexgaurd.:)