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View Full Version : Grout question/Does it take 3 days to dry?



highclassbrass
01-22-2008, 09:43 PM
OK< so I'm a musician and NOT a plumber. But I did stay at a Holiday Inn Express last night...

My question: I had a leak where my soapdish was in the shower and it eventually flooded my carpet on the wall opposite the dish. I replaced a 17 inch by 12 inch hole with backboard and then retiled (no soapdish thank you) with combination pre-mixed adhesive and grout/unsanded. This was on the advice of the guy at Lowe's.

Anyway, it looks great if I must say so myself. I nailed the backboard into the 2x4 and the tile is lined up nicely. The adhesive/grout says to wait 72 hours before using. It that necessary? It went on real sticky and tight and looks to be secure. The reason I am impatient is I have the carpet guy coming in 2 days to replace the pad and I want to make sure it's not leaking before I go to all that trouble.

Thanks.....:confused:

jimbo
01-23-2008, 07:03 AM
What did you do to make this waterproof? It was not done correctly the first time, or water would never have gotten into the wall. Grout is not waterproof, and neither is backer board. There should be a water proof membrane ( plastic or 15 pound felt are two types) behind the backer. Joints on the backer taped with mesh and mudded with thinset. The adhesive to attach the tiles should be thinset, or if mastic is used it must be rated Type 1 ( like AcrylPro brand.). Regular "combo" mastic and grout is not suitable for a shower.

Now, for the good news. Your repair will probably be fine, and water will just run off the surface, and probably you will never have any leaks behind there.

For excellent details and advice on tile work, visit the tile forum: www.johnbridge.com

highclassbrass
01-23-2008, 07:42 AM
Thanks for the info. Grout is not waterproof? That makes no sense. Are you saying water can get through it? There's nothing between the tiles except grout. How can that be, not waterproof?

Behind the grout and tile is the backerboard, nothing else, and the backerboard is just 1/2 inch cardboard crap. The soap dish had come loose enough that the backerboard behind it was wet. I cut away all the wet area until I got dry backerboard, just a small square.

I'll keep an eye on it. When can I test it?

jgrimes227
01-23-2008, 08:13 AM
Grout is porous! After you grout any ceramic job the grout must be "sealed". If you don't water will seep through it, mold and even mushrooms can grow in it, it will rapidly deteriorate and the tile will begin to pop off the adhesive that cements them to the sub-surface - and if the sub-surface is plywood - it will rot.

Sealers are usually nothing more than a silicon based liquid. It is usually clear and has the consistency of water. Sometimes it comes in a smallish bottle with a built on small brush and you simply apply the sealer by brushing onto the grout joints. The grout should definitly be dry or you simply seal the remaining water in the grout mixture in the grout. For me I would seal the grout joints before ever wetting the grout again after installation - 3-4 days drying time. And then do it again a month or so later. The fastidious among us will give a shower a major cleaning once a year or so - getting rid of all the soap scum, re-caulking where needed and then re-sealing.

A Cautionary Tale: many cheapo or itinerant tile setters never seal the tiles they set. They will set the tile, grout it and they are gone. They simply don't want to come back three days later and seal it. They won't tell the homeower that the tile needs to be sealed - ie telling them they are not getting a completed job, and a few months or year later, the tile starts coming up - especially around the shower. In my experience I have seen several instances of this.

highclassbrass
01-23-2008, 08:25 AM
Thanks very much. I'll get some sealer today. I think I saw some spray on types at Lowe's.

jadnashua
01-23-2008, 03:54 PM
That mastic under the tiles could take a month to set (if ever depending on the size of the tile you installed). It stays flexible in the bucket for a reason, no air. Stick a big tile on top and guess what, no air. It will dry (very slowly) through the backer board (hopefully this was a cement based backer board and not drywall or greenboard). Until the mastic dries, the grout can look wet.

There are all sorts of people that have had health problems with some of the spray on grout sealers...it isn't a big deal to use a foam brush to put some on - stay away from the sprays. You get what you pay for on sealers...the good stuff is as much as $150/gallon. Now, you'll only need a very small amount - unless the grout lines are huge, for a shower, a pint may be overkill and last for the rest of your life (you need to reapply maybe in a few years depending on the quality and how often you clean the shower). Do NOT let the sealer dry on the tile - it will leave splotches. The instructions specifically say to buff off any that isn't absorbed before it dries. Don't worry if you get some on the tiles, just make sure to wipe it off before it dries - you need to give it time to be absorbed into the grout, so don't do it immediately. In the winter, with the relative humidity low, you will not have as much time as during a humid summer day.

frenchie
01-24-2008, 12:26 AM
Thanks very much. I'll get some sealer today. I think I saw some spray on types at Lowe's.

DO NOT use the spray sealer.

http://www.yourlawyer.com/topics/overview/stand_n_seal

http://www.lawyerworks.com/stand-and-seal.php

http://www.standandseallawyers.com/

http://www.cpsc.gov/CPSCPUB/PREREL/prhtml05/05253.html

Although, if your blowes is still selling it... you might still want to buy a can, and claim you used it... :D

jimbo
01-24-2008, 06:38 AM
. Grout is not waterproof? That makes no sense. Are you saying water can get through it? There's nothing between the tiles except grout. How can that be, not waterproof?

Behind the grout and tile is the backerboard, nothing else, and the backerboard is just 1/2 inch cardboard crap. The soap dish had come loose enough that the backerboard behind it was wet. I cut away all the wet area until I got dry backerboard, just a small square.

?

Your shower really was done wrong, although in years past that was not uncommon.


Yes grout is VERY porous, so you must assume moisture will penetrate it.

The proper foundation for shower tile starts with a visqueen or 15# felt roof paper on the studs, then a 1/2" thick mortar bed with wire reinforcing ( today much easier to use cement backer board. all joints taped and mortared.). Then proper thinset mortar and tiles. Tile joints grouted, but all joints at a change of plane should be caulked, rather than grouted, due to likely movement. This means the corners, and the tile to tub joint.

Tile on wall board will result in mush, and unfortunatley it is quite likely the walls behind your whole shower are in sad shape;