July 9, 2009 11:23 AM   Subscribe

Grout - how do I remove it without removing shower tiles? Pictures and detailed question inside.

The grout that creates the seal between my tub and the bottom row of shower tiles is cracked and in some places has gaps. I would like to remove just this line of grout between the tub and tiles and replace with caulk. I bought a grout tool but it doesn't seem to make any headway against this concrete-like material. How do I get the grout out without removing the tiles?

Here is a pic of the basic set up.

Here is a close up of the general grout line sealing the tub

Here is a close up of what happened when I tried to use the grout tool - note I could not get more than the already loosened grout to come out.

Do I need a grout saw? Do I need to remove the tiles entirely and regrout the upper seam and the caulk at the tub?
posted by spicynuts to Home & Garden (11 answers total) 5 users marked this as a favorite
You don't. You clean it and grout over it. Caulk over that.
posted by bensherman at 11:39 AM on July 9, 2009

You can get a little tiny attachment for a Dremel tool. I am not sure if it's specifically for grout removal or just a little tiny head. But it will probably work.
posted by FergieBelle at 11:40 AM on July 9, 2009 [1 favorite]

Best answer: I use a small grout saw like this -- it should do the job on the grout (which is, in fact, concrete, no just concrete-like :))

A dremel should work as well, though you'll probably burn through a number of bits.

If it's cracking like that, don't bother grouting over it -- it will just crack again. Get as much of it out with the grout saw as you can, then do a nice clean caulking job and you'll be all set. Definitely do not need to remove the tiles.
posted by Pantengliopoli at 11:57 AM on July 9, 2009

Yeah, you need a grout saw. It's miserable, slow work, but you can do it. I've had bad luck using a Dremel on grout, but if you have a rock-steady hand, you might do better.
posted by adamrice at 12:06 PM on July 9, 2009

Yes, the grout saw. And, yes the caulk rather than the grout. Use mildew proof, or very resistant, caulk. 100% silicone is the best.
posted by Midnight Skulker at 12:25 PM on July 9, 2009

Midnight Skulker is right, right, right.

Don't grout any joint where planes intersect. That means corners, or where the floor meets the wall, or where the tile meets the tub. Everything is moving all the time, and grout won't flex and adapt to even small movement. Caulk will. That means it won't crack and chip out and leave gaps that water can get into. And water is the homeowner's worst enemy.

And yeah, you're gonna be hating life on the end of that grout saw- but it's the best way to do what you need to do.
posted by Shohn at 12:51 PM on July 9, 2009 [1 favorite]

Correct, odinsdream -- there's no need to grout where the wall meets the tub (or at the intersection of planes, as Shohn says). Just use a good silicone caulk on a clean joint. Grout at those joints will (likely) eventually crack and need to be replaced. Caulk is much more flexible.

For what it's worth, grout (being concrete) isn't waterproof, so your real water protection is (or should be) behind the tile. Any water that manages to get through the grout/tile should be running down your liner (Kerdi, poly plastic behind CBU, etc) and getting to your drain that way.
posted by Pantengliopoli at 1:03 PM on July 9, 2009

Just in case the OP and odinsdream need another opinion at this point, let me concur with the others. I've done a couple of tiling jobs, and done a ton of reading on the subject. Grout shouldn't be used at dissimilar surfaces or at intersections, caulk should. I'll add that there are a *ton* of tile jobs out there (especially commercial) that seem to disregard this. That's only fine if you don't mind cracking.

If the gap to be caulked is much larger than about oh, maybe 3/16" or so you should use foam backer rod, since caulk isn't made to fill large gaps. It'll also be much easier to caulk.
posted by RikiTikiTavi at 1:31 PM on July 9, 2009

You got it odins -- grout on the planes, caulk at the corners. If the shower is well constructed (i.e. appropriately waterproofed) grout at the corners won't harm anything, it will just eventually crack and require repair.

RikiTiki makes a good point about the gaps, too -- if they're really large, foam backer rod will come in handy.
posted by Pantengliopoli at 2:01 PM on July 9, 2009

Response by poster: Considering my interactions with the builders over the last 9 months, I better make sure there is waterproofing behind those tiles. This is new construction and they obviously ignored the advice I'm getting here...there is grout at ALL intersections - tub/tile, tub/floor, tub/wall, etc. Ridiculous.
posted by spicynuts at 6:40 AM on July 10, 2009

Grouting all the intersections isn't uncommon and doesn't necessarily mean it was poorly built -- when I did my shower I grouted a few of the intersections, knowing that I would probably have to redo them eventually. If it's really solidly built, it may last a long time (though new construction usually settles and shifts for a while, so yeah -- bad idea there).

Feel free to memail me if you want more info on getting into the wall to see what's back there. Many, many showers are built without waterproofing behind the tile. In a tub/shower, it may not be the end of the world -- much bigger problem in a full tile shower.
posted by Pantengliopoli at 8:00 AM on July 10, 2009

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