Unsealed concrete board [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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01-01-2017, 07:06 PM
A number of years ago, 6-7, I installed a tiled area around a tub but I did not seal the 1/2" concrete board. I did tape and mud all the seams and joints with thinset. Fortunately the tub area is not in an area were water seepage can do any damage to the house and the outside of the walls are open to the attic. I have never seen any seepage and I keep the grout sealed periodically. Other than sealing the grout, is there anything else I should be aware of since the concrete board was not sealed?


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Tool Guy - Kg
01-01-2017, 07:59 PM
Welcome to the forum, Jim. :wave:

You're using the word "sealed" in a unique way that's a little confusing to me. Are you saying that you didn't waterproof the front of the cement board?


01-01-2017, 08:02 PM
Did you install any sort of moisture barrier behind the cement board? If you didn't than I would guess you won't see much from the outside. The damage that can occur is usually contained behind the CBU in the form of mold, mildew, and water damage to the studs. It's hard to say whether you'll have any issues in the future. Extreme case of poor prep results in water leaking through the subfloor, grout lines cracking, tiles popping, and mold growth making its way to a visible area.