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I have shower floors made of porcelain mosaic tiles which have grout shrinking away from the area where floor meets wall. From reading your past posts, I suspect the grout may have been mixed with too much water, but why would this only happen around the edges, and how should it be repaired? GC wants to use caulk; I prefer getting the tile contractor back to use proper grout…
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Sorry Carole, I go with the GC's recommendation to use caulk. What you have is a classic case of seperation at the intersection of two planes.
Think about it: every house moves. This would be most evident where wall meets ceiling, countertop, or in your case, floor. The appearance of cracks does not mean you have an inferior house.
You could add more portland cement-based grout to the crack, hoping it too won't crack. It is the differential movement of the house causing the crack. Caulk has the elasticity required to bridge the crack without it too cracking. There are available caulks to match the color and texture of your grout.
*I am not a tile setter, but the best tile guy in my area agrees with Rich. Caulk where two planes intersect. But you might want to see a sample of the actual dried caulk before deciding if you want the "matching" color.Rich Beckman
*Carol, I agree with the Riches. Dig out the grout and caulk. This happens at inside wall corners as well. Don't fill the cracks with more grout, it will only crack again when there is movement, and after a few cycles of filling cracks you'll get tiles popping off. You can get colored caulk to match any grout, even sanded.
*Caulk is a good way to deal with the intersection of two planes, however, this cracking in a shower could be an early indication of greater problems. I have never had a problem of grout cracking at this corner in a full float installation, so I suspect that the walls have a different substrate, backer board perhaps or, horrors, green board. It would do well at this point to besure that your installation is adequate, while you still have the options of corrections being made by the contractors involved.
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Mike,
I gather from your post that floor and walls should have the same substrate- I'll have to put that question to the GC. I THINK they do, with the floor having the addition of a membrane going part-way up the wall...But if they turn out to be different, what course of action would you recommend? This is also important to me because I have another shower which will be going in during the next month, and if there's a better way I'd like to know now...
*...the wall and floor substrate is Durock, and the membrane under the floor tile and part-way up behind Durock wall is a flexible material made by Triple S Specialties Corp.
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Carole, in my opinion the best installation is a vinyl shower pan liner over a concrete base and turned up the walls. The bottom of the shower and the walls would then be floated, so that the walls and floor of the shower would essentially be monolithic. This is also the most expensive. There is nothing wrong with backer board (Durock). I won't risk stepping on any toes by suggesting that it is not the best way to do a shower floor. Your description of what you have sounds like it would be okay, but definitely go with the caulk in the inside corner. Most shower drains require that the membrane be clamped between two parts under about 1 1/2" of mud. I wonder what kind of drain installation you have with backer board. In the future you might prices on a full mortar bed on the shower floor with backer board walls. Or, a plastic or fiber-glass shower pan with tile walls. Rich is far more experienced than I am, so I hope he will comment further.
*"Rich is far more experienced ..." Mike, you really mean that? I wish all my customers would say that, because most think they know more than--oops, wrong thread; anyway, thanks, pard.Carole, something I don't understand: if the showerfloor is Durock with waterproof membrane underneath, what is providing slope for water runoff? And what, other than gravity, is holding the Durock in place?Before you get all excited and start questioning your tileman 'cause something you read on the 'net, please let me know if I'm right.Wonderboard, Durock, et al, are materials that have come onto the scene to make the job easier. They have usurped the role (and the expertise of knowing how) of traditional installations. Hey, just like drywall takes the place of plaster.Well, not quite; there may be ways to install drywall incorrectly, but I assure you, there are many ways to install tile backerboards incorrectly. Or, more accurately, there are some type of installations where these products don't belong. Example: backerboard in showerfloor: how is adequate (leakproof and longlasting) seal made at drain? Is it superior or inferior to traditional mud mortar setting bed installation?Comments please.
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Rich and Mike, and everyone,
Thanks for all your help. I guess I wasn't being clear- the floor has backer board, a membrane, and THEN mud, under the tile...
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Carole:
"..the floor has backer board, a membrane, and THEN mud, under the tile..."
So, why the backerboard? Is this a "preslope" for the membrane?
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Contractor probably used backer board under membrane because I expressed concern about sloping all those 1" tiles to the drain, and he had extra pieces around. Was that a bad idea?
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No, Carole, I don't think that is a bad idea, per se. But I do question the integrity of such a job. I guess I'd have to see it or talk to the tile guy before I could comment further.
BTW: from your many posts on this forum, I think you are rather calm about what usually is a nerve wracking time for the homeowner. This, in my book, makes you a candidate for "Dream Customer".
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"Dream customer"? thanks; that depends... My contractor has seen me through my husband's serious case of lyme disease (likely contracted on the site), my 2 children's weddings, plus a death in my family all over the last 6 months...while we were trying to make important house decisions. Now I'm probably driving him crazy with all the questions I have since I found this site!
*As a tile setter, I would recommend removing the old loose grout only. Try and use new grout from the same bag as the old with the same consistency as the original to ensure a close colour match.When the new grout is dry caulk with a mildew resistent silicon in all the corners.I do this at ever corner and have no related call backs.If you don't use the caulk it will crack every time, no matter what you use for materials!One more point, it's a good idea to use a grout ceiler on "ALL" joints (2 coats) before you apply the caulking.
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I have shower floors made of porcelain mosaic tiles which have grout shrinking away from the area where floor meets wall. From reading your past posts, I suspect the grout may have been mixed with too much water, but why would this only happen around the edges, and how should it be repaired? GC wants to use caulk; I prefer getting the tile contractor back to use proper grout...