To Caulk or not Caulk. - Contractor Talk - Professional Construction and Remodeling Forum

HandyHails · 03-09-2009, 04:56 PM

I'm putting the finishing touches on a bathroom remodel tomorrow. I put in a three piece tub unit from Sterling directly on the 3/4" sub floor. Cement board and 12" x 12" tile on a 45 against the tub. 1/4" joints w/ sanded grout. My question is whether or not to try to caulk up against the tub on top of that grout line. I'd rather not as I'm pretty sure it will look like

, but I don't want any problems down the road w/ water getting in there. I laid the tile last week and there is no separation between the grout and tub as of yet.

Whadduyathink?

angus242 · 03-09-2009, 05:07 PM

Quote:

Originally Posted by HandyHails

Whadduyathink?

You messed up.

Any change of plane needs to be caulked, not grouted. It's in the TCNA handbook.

HandyHails · 03-09-2009, 05:17 PM

I could go ahead and grind that grout out of there. It would only take like 10 minutes. I think that's what I'll do.

Thanks Angus!

By the way would the change of plane include the marble threshold as well?

Rob79 · 03-09-2009, 06:27 PM

If you mean where the tub meets the tile and you only used cement board you will probably have to caulk.. I kerdi over the tub flange, then I will grout. I am totally against using caulking where the flange is. If water gets behind the tile it will run down and get trapped where you used caulking, it has no where to go. I would rather replace grout that possibly could fall out than have a moldy disaster. Just grout where the marble thresholds are.

TileLady · 03-09-2009, 08:01 PM

TCNA guidelines. You have to caulk that area. The constant movement of the tub will cause the grout to crack. Once the grout cracks, water will get in there and under the tub.

I've seen so many instances where contractors are lazy and don't caulk in front of the tub. The grout ALWAYS cracks!

Rob79 · 03-09-2009, 08:36 PM

If you use the caulking, fill the tub up with water first and then caulk. Yes there is a chance for the grout to crack as I previously mentioned. Definately not all the time. Water will get in the grout and you want it to escape at the bottom where the grout is. It will stay trapped with caulking. If you use the silicone you will see in a few years about the trapped water. I have been doing bathrooms for 15 yrs. & I found this is the best method. Not LAZY just EXPERIENCE. Think about both methods and use your own preference.

MattCoops · 03-09-2009, 08:58 PM

How does water get through siliconized caulk? We're not using white lightning here. If you're using TEC grout, for instance, TEC makes a siliconized caulk (sanded and non) that matches color for pretty much every color grout they put out.
I usually set DensShield atop unmodified thinset over whole subfloor (even under tub and cabinetry), tape mud the seems, screw down, then come back and coat the screws/joints with liquid waterproofer. Now you have a completely waterproof floor. No rot. No stains on cieling below if a flood or mishap occurs. Slap a 15 yr warranty on the job and its sold!

Rob79 · 03-09-2009, 09:07 PM

Water will not go through caulk, that is the problem I mentioned. Grout is not waterproof so it will penetrate the grout joints and not escape at the bottom where the caulk is. If you use grout at the flange it has a place to escape.

Splinter · 03-09-2009, 09:21 PM

Rob79- He's talking about floor tile here, not wall tile over the tub...

Remove the grout... Another issue besides a crack forming is squeaks. The slightest deflection in the acrylic tub will cause the loudest damned squeak as they step in and out caused by the plastic tub rubbing against the hard grout.

Rob79 · 03-09-2009, 09:26 PM

Thanks Splinter, my bad

. Definatley the caulking there.

HandyHails · 03-10-2009, 04:06 AM

Thanks guys. I'll take care of it today. I appreciate all the input.

JazMan · 03-10-2009, 06:45 PM

I also recommend either acrylic or siliconized acrylic caulk. I do not recommend 100% silicone in any tile installation where it is likely that the surface may get wet on both sides. It seems to trap moisture more than acrylic caulks and turns black.

Matt,
You changed to subject to floors, but why are you using unmod under DenShield? Also NO WAY will that floor be watertight

unless you flash a membrane up the walls and make a curb too. If you spill a bucket of water on a floor done that way, the water will get downstairs before you're able to get there.

Jaz