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Bathroom tile grout repair

8341 Views 36 Replies 5 Participants Last post by  oh'mike

I'm looking for a Sunday project and I'm hoping someone here can help.

Our bathroom was neglected by the previous owners and parts of it look awful. We have a bathtub and the time grout all around it is chipping, cracked and dry-rotted.

I'm okay with re-caulking around the tub, it's just the hard grout between the tiles.

How can I go about fixing or repairing this? I was hoping to not rip out all of the tile and start again...

The pictures below are just a few examples but its all over around the tub.

Any help is much appreciated!!

Any help is appreciated!


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That is not grout failure---

It is a sure sign of tile not bonded or a moving substrate---

Your time will be wasted ,regrouting that--it will simply crack and fall out in short order--

I've seen that many times---sorry-----
The fastest way is with an ossilating saw and a diamond blade.

Short of that you can use a hand grout saw.

I could be wrong since I'm not there to see it but it looks like someone tryed to use sanded grout, the gaps are small so unsanded grout should have been used instead.
Any place the tile changes direction, under the tub, at the base of the tub color matching caulking should have been used not grout.

Also to have that much grout fail just may be something went wrong with the install. I'd be pushing on the tile to check for loose tiles.
I own one of those saws with that blade. So If i understand right, I use it to grind out the bad grout, but what is the next step? How do I replace it?

The house was built in 2000 and its the original tile work from the builder. I figured the old owner left a lot of water laying around which ate away at it, but I could be wrong.

Also, there are no loose tiles. I found one corner tile which is partially lifted up but it's tight and not moving.

Thanks for the advice
I"m with Mike on this one.
Those drop in tubs are far more prone to leaking under the tub.
It almost looks to me like they just used the thin set that came up the sides of the tile instead of a real grout.
The tile work in the pics shows that the substrate has gotten wet, it's shot. Remove the grout in the corners and caulk. Just touchup the rest to buy you some time.

The work was not done right in the first place. Typical cheap tile work.

Ok so I sanded everything down with the diamond blade and hand tool. I then took the pre-mixed grout and spread it like I researched, followed by a light sponge to remove the excess.

The bucket says "bright white" but it appears to be more of an off-white. Does it get whiter as it dries? Also, the texture seems more grainy. I left the back splash alone because it was in good shape, my work and the back splash look completely different.

Did I buy the wrong stuff? The bucket says good for 1/16-1/2 gap.

I also bought sealer for when it cures.

Looking for advice!


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#1 I never would have use premixed grout.
#That sure looks like sand grout, for that small a gap I would have used unsanded. what? Scrape it all out and try again?
Did I buy the wrong stuff? The bucket says good for 1/16-1/2 gap.
Yes you did, it's wrong on both fronts. It's pre-mixed and it's obviously sanded. what? Scrap it all out and try again?
If it's a large area I might just leave it alone. It's only a temporary fix anyway.

Did you use the same stuff in the corners? You should have used caulk as mentioned before.

Those cracks tell you it's damp behind the tiles. Tiles do not make a wall or floor waterproof. Grout is not a waterproofing. The substrate got wet and expanded. So now you have/had cracks. Probably kinda moldy back there too. How does the room smell?

It is a temporary fix, but I want it done right regardless. I went out to HD and picked up the no-sand bright white mixing powder. I'll scrape it all out tonight and start over tomorrow.

They had bright white and "dry white" anyone know what dry white is?

EDIT - I just finished grinding out the sand graut - what mess. I worked on it for about 3 hours and got as much as I could but you can still feel some little pieces of sand here and there no matter how much I clean it. Will this cause a problem with the non-sand graut sticking?
Bright white is a color, dry white describes the product...I think. It's Polyblend from HD? I don't see those colors listed.

Try brushing the joints to clean them out. Damp sponging helps too. Did you get caulk?

I did all those techniques so we will see...I went all over it with the shop vac as well.

I did buy caulk but I was going to apply it last once the grout is in place and set. I bought kitchen and bath DAP with microban. So right now it's not applied.

This is our master bathroom so we are just using the other upstairs bathroom until we get this finished. I have the water turned off on the tub for now.
Ok, you'll see how it works out. Once moisture gets behind the tiles it soaks the substrate (which might be the wrong material such as wallboard or plywood), and it's not gonna dry. Often the new grout and caulk will just mold again. You should be able to get a few more years if you aren't ready to redo it now.

Yeah a few more years would be good - I'm going to try and upkeep it as much as I can, but I get moisture may seep back the other way (assuming it is wet under the there)

I don't know what the tile is glued on, but I took off the grille under the tub and it looks boxed out with plywood - but that doesn't mean there isn't something sandwiched between the wood and tile.

So even though there is some trace of sand here and there (I don't think I will ever get ALL of it) I shouldn't have a problem with the non-sand sticking correct?

Also, are any additives recommended or is just water ok to mix it with?

Sorry for all the questions - I really appreciate the help so far!
Also, are any additives recommended or is just water ok to mix it with?
I don't know exactly which product you have. I asked whether it was Polyblend earlier. If it's from HD it should be Polyblend and is added to water.

Oops - sorry about that. Yes, it's Polyblend brand.
Ok so new grout is in place and I think it looks good! My only issue is I'm having trouble getting the cloudiness off the tile. I tried sponging it 7 hours later and it looks good until it dries and it gets cloudy again.

I'm going to do the floor tomorrow as well a the caulking around the tub.

Now for the bad news - one of the tub valves leaked and it put water through the floor and through my laundry room ceiling - the water came out in the light fixture which filled with water and smashed on the ground from the weight - the drywall was all mush too - the fun never ends...


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Ok, looks much better. The grout film needs to be wiped and buffed with dry cloths. There may still be old surface film like we saw in the old pics too. I suggest you let the grout cure a couple weeks, then clean with acidic tile and grout cleaner followed with grout sealer.

A couple weeks? I thought you could seal it after 3-4 days?

Also, what is the process for sealing? I bought the "surface guard" sealer.

Just spray in the grout lines let it sit and wipe clean?
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