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How long should grout set before sealing

svctech's picture

I just completed a small project to re-tile my shower.  My split-level is almost 20 years old, and was built by Joe Cheapo Construction.  The shower walls were 4x4 tiles glued (no mortar) to white 1/2in gyp board and grouted.

I tore it all out, let the wall cavities dry for over a week, and hung Hardibacker floor to ceiling.  I was able to re-use the existing floor pan after actually attaching it to the studs (the only thing holding it to the floor was the drain).  I set all the wall tiles,  then I completed the grouting about 2am Sunday night. 

How soon can I begin to apply caulk, install the door, and trim-out the plumbing.  The instructions from the grout says 21 days.  It's getting a little old dodging rubber duckies and Barbies in my 3-year-olds shower/bath upstairs.

Thanks for your help!


(post #61629, reply #1 of 5)

Good news, bad news.  You can seal the grout after a week or two...longer is better...but first you need to rip out all the tile and start over.  If I understand your description correctly, your construction consists of tile over hardie over wood studs...right?  What happened to the membrane?

To answer your other questions, you can caulk, install the door and trim the day after you grout.  And you can start using the shower the day after you caulk.  When it comes time to seal the grout, just clean it well and let it dry before sealing.  The longer you wait before sealing, the more chance of it getting stained, but just using it for a shower (no food prep) is relatively low risk.


Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

I'm sorry, I thought you wanted it done the right way.

(post #61629, reply #4 of 5)

Thanks for your response, Ed (and others). I worked for a remodeling contractor for about two years doing-in my opinion- medium to high quality renovations and remodeling. He was very particular about how his tile went on the walls, and with the time he spent prepping, I felt his technique was the standard. In one case of a two-story addition, the new children's bathroom was above the enlarged kitchen. He wanted no part in having water splashed on the floor and leaking onto the smooth kit ceiling. we hung Hardie to three feet off the ground and five feet from the tub, and also covered the subfloor completely before the plumber came in. After mesh tape and a complete skimcoat of mortar, the plumber was allowed in to set his tub. (yeah, I know. Plastic, Copper, Tub, then walls. Dude was crazy!)

anyway, I had never seen a barrier go up before Hardie and assumed the best. Luckily, I make my living fixing electronics. I value all the professional input from everyone.

Thank you very much.

(We ended up replacing some of the kitchen and the closet that backed up to the bathroom in that 2-story. The plumber forgot to sweat the cap on the hot air chamber at that tub. (probably because he had to work from the back-side of the wall) Since the place was gutted, we had all the water off downstream of the spigot by the meter. He turned the water on the day he finished trimming out his fixtures. Water was coming out of the can lights in the kitchen! I went back to my previous career within a couple months.)

(post #61629, reply #5 of 5)

People have not used membranes with success, so it will probably be ok.  The grout doesn't have to dry, because it's a cementitious product and cures by hydration.  If you use the shower for a week or so before sealing, just be sure you clean the grout well with an appropriate the sealer instructions.


Whenever you are asked if you can do a job, tell'em "Certainly, I can!"  Then get busy and find out how to do it.  T. Roosevelt

I'm sorry, I thought you wanted it done the right way.

(post #61629, reply #2 of 5)

well now that you have read Ed's reply and your sick that you didn't put tar paper behind the hardi board, don't sweat it to bad, i think it's great to have the paper back there ,but i very seldom  do it. your plain old drywall board lasted 20 yrs, i suspect by the time the hardi board has leaked and you tear out again [what 20-30 yrs] you will be ready for a new tile  design! anyway i would  just get my own rubber duckie so i wouldn't have to share !and give the grout plenty of time.  larry

the older i get ,

the more people tick me off

(post #61629, reply #3 of 5)

I agree with using the shower the day after you caulk, however disagree with using the shower before you seal. If you don't use ANY soap it's okay. The soap will leave a film in the nooks and crannies of the grout and that's exactly where the sealer wants to go. Some (cheaper) sealers leave a film on the grout and may not bind if there is a film of soap on the grout. Penetrating sealers (cha-ching) will have difficulty penetrating the grout if there is a soap film to penetrate first.

The reason for the wait time is to allow the moisture from the thinset and grout to evaporate. If you seal to soon it will take longer for the thinset to cure.

With all the effort you put in so far, what's 19 more days? And no more work! Wait a week, as long as it's summer and not humid where you are, and seal. For now, go ahead and caulk and install the door.

Flay your Suffolk bought-this-morning sole with organic hand-cracked pepper and blasted salt. Thrill each side for four minutes at torchmark haut. Interrogate a lemon. Embarrass any tough roots from the samphire. Then bamboozle till it's al dente with that certain je ne sais quoi.

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