What We're Working On: My Grout

If you’ve been following along, you know I changed out the bathroom heater for a fan that actually vents to the outside. Now that that’s done, it’s time to address the mildew that comes from inadequate ventilation, and a poor installation of the tub and tiles. When you install a tub, the joint where the tub meets the wall should be caulked, not grouted. This joint moves and flexes as the tub is filled and emptied, as the air warms and cools, as water gathers and dries. While caulk can handle these variations, grout will simply crack. And cracked grout is an invitation for moisture to get behind the tub and tile and foster the growth of mold and mildew.

My mission, remove the grout and replace it with caulk.

The Right Tool for the Job

Removing the old material is the first thing you have to do, and it’s the only challenging part of this project. That and deciding the best way to do it.

The One Off - From time to time a new tool or product to test gets delivered to the 10th floor of the DoItYourself Building, and by chance one came not long ago touted as a grout remover. It’s a bright red, plug-in tool about the size and shape of a hummingbird, with a chisel point beak. Plug it in, turn it on and apply the chisel to the grout. According to the package it will eat through an inch of grout every second. That may be true under perfect conditions, including grout less than a year old and perfectly dry.

Grout remover

It powered the grout as advertised in certain spots, but as dampness was the root of the problem (and will be for a lot of people removing their grout) the fact that the thing bogged down whenever it contacted any moisture made it practically useless. This was about what I expected. Although I approached the tool with an open mind, I’m not usually a fan of single-use tools.

The Multi-Tool - One great multiple use tool is the Dremel. So I went and got that and selected an appropriate bit. I bet there’s a bit specifically for grout removal, but I don’t have one. Instead I used a little terrifying spinning wheel like a dental instrument.


It worked great. However, once again, old construction issues held me back. Installed incorrectly to begin with, sometime after that someone tried to address the grout/mildew problem by simply caulking over it. So not only was there a crappy old grout job in front of me, but there were patches of a crappy old caulking job covering it up. While the dremel cut smartly through dry and moist grout alike, when it hit the caulk it would catch, jump and burn the stuff up. Not a good smell at all, and again I was slowed down.

The O.G. - What do you do when the specialty tools can’t get the job done? You do what you should have done in the first place. Grab a hammer and chisel. With the oldest of old school tools I knocked it out (literally) in a matter of a few minutes.


You do have to be careful here, ‘cause this is the same set of tools you’d use to remove the tile, and you don’t want to do that. Keep the flat of the chisel level with the rim of the tub and tap a corner into the grout. You can buy a bit of an advantage by starting where the grout is already chipped or cracked. Keeping the chisel at about a 45-degree angle off the wall, tap it forward through the grout. The old grout will slide out in chunks, and the old caulk just curls up and peels away.

chipped out grout

Sealing the Deal

I cleared out the open gap between the tile and tub with a thin, rigid putty knife, getting the area as clean as possible. Then I came back with a tube of tub and tile caulk and ran a bead around the tub, filling in the whole joint.


They make a tool just for smoothing and shaping the caulk in exactly this situation, but I do not have one. That’s because the best tool for this is your finger. Run your finger down the bead, removing the excess caulk and creating the perfect profile for water to seamlessly cascade from the tile, over the caulk and into the tub. Just have a wet rag standing by to regularly swab the buildup from your fingertip.

Smoothing the Caulk

smoothed caulk


If there’s another step that’s difficult, it’s this one. Before you can use the shower, you have to allow the new caulk to cure. For 36 hours. Seriously. That’s a long time. Before you take this article and use it as a model for your own grout removal/caulking project, let me amend what your first step should be.

Step 1

Pick a time to do this when you can wait 36 hours before taking a shower, unless you want to use the shower your teenagers use.

The cleaned up tub