Help Mike, Bud, Jazman: Cracks in grout line in new tile wall.

Jim F · 05-19-2011, 04:39 PM

As some of you are aware I have a recently remodeled bathroom Jim's downstairs bathroom project I'm thinking there is expansion in one of those bood blocks I installed for a grab bar backer or that it was thumped really hard by one of the kids.

Open to suggestions as to the cause. More importantly though is how best to fix this. I read somewhaere that I could tremove all the grout from these joints and mix new grout with some sort of flexible modifier. Most of th info addresses corners which are not a problem as the already have silicone.

My other thought is to relpace the cracked grout with a matching caulk (not silicone).

Bud Cline · 05-19-2011, 06:52 PM

Jim I just went through your entire thread and I don't see anything that would cause any movement. The blocking doesn't appear that it would or could be the cause. I would be curious to know what is on the other side of that five foot wall.

I did notice the studs used for the shower appear to be 2X2 but there were so many great pictures I didn't read the whole thread to know if that is the case. Obviously the studs are tightly shimmed to whatever that wall is behind them.

My first "guess" and it is only a guess is that the cracking could be caused from some kind of impact to the wall. Hopefully no one has fallen while in the tub/shower.

I'm wondering if the issue that caused the cracking could have come from the other side of that back (5') wall.

If unsanded grout was used (and it appears it was) that stuff has been known to crack on its own. Especially if mastic is used for the adhesive.

**oh'mike** · 05-19-2011, 07:39 PM

How much cracking --how extensive?----I look at your framing as you built that--every thing looked O.K. to me then.

Don't use caulk as a repair--it changes color and looks ugly.

Take a knife and remove the offending grout---replace with some fresh product--you might have mixed it wrong---or over washed it --or had some stale product that was already subject to moisture.

There is a liquid latex add mix that will make the grout much harder and stickier---

Extra care must be taken in cleaning if you use the add mix----the 'haze' won't wipe off with a towel

So don't leave any 'haze'----More info please.

Jim F · 05-19-2011, 08:50 PM

They are just really fine cracks that go in a straight line and go almost top to bottom vertically. Two rows are involved that I can see. There is one horizontal row that is also cracked for about half the length of the back wall. I haven't had the opportunity to photograph the cracks yet.

It is feasable that my daughter hit hard against it or fell against the wall. She has Autism and can be very rough on fixtures and could not tell us if she did it. That was why I went with the cast iron tub in the first place.

Bud, The back wall had 2x2's furred out to center the drain away from the joist. They rest on top of furring strips that are thicker on top and taper down to almost nothing at the bottom when the builders originally put on that addition. That was the outside of the house- wood siding.

So I'm reading that I should first try removing that cracked grout and remixing some new grout with water to fill back in before I resort to any kind of grout modifiers. And that I should also buy a new box of grout because what I have left over may be no good. Is that correct?

**oh'mike** · 05-19-2011, 09:08 PM

That's right,Jim---Some times cement product get stale if exposed to humidity--I never trust old products.

Open up the joints with a utility knife and regrout the affected areas---the grout additive is a good product,if you wish to use it.-Just make sure you wipe the surface clean--(a micro fiber rag like you might use to wash a car) gives a nice final wipe down.--Mike---