If the grout in your shower corners keeps cracking, or there's a gap opening up where your countertop meets the backsplash, there's a good chance the joint has the wrong material in it.
Here's how I explain it. When there are two different surfaces meeting, such as a kitchen counter and a backsplash, I recommend an appropriate caulk, because it allows flexibility when it comes to any movement. Without that flexibility, movement can open up a gap and let water in.
Grout goes between the tiles. Caulk goes where surfaces meet.
Grout is the hard, cement-based filler between tiles on the same flat surface. It's great at that, but it doesn't stretch.
A "change of plane" is anywhere the surface changes direction: an inside corner where two shower walls meet, where the tile floor meets the tile wall, where the tub meets the tile, or where a counter meets a backsplash. Those spots move a little as the house shifts and temperatures change.
The tile industry's own standards agree. The Tile Council of North America's handbook calls for movement joints at all inside corners. The ANSI installation standard says movement joints must be kept free of setting and grouting materials. In other words, a flexible sealant goes there, not grout.
Probably the biggest thing here in Southern California is shifting or movement. Around Chula Vista, the rest of the South Bay and East County, that's often why a grouted corner cracks.
"But I want it to all match"
I understand this one. For a nicely tiled shower, sometimes people would like to keep all grout for aesthetic purposes. In most cases, though, I recommend caulking at the base, where the tile floor meets the tile wall in the shower. Caulk comes in colors made to sit next to common grout colors, so the corner doesn't have to stand out.
What to check in your own home
- Shower corners and the floor-to-wall line: hairline cracks or crumbling grout there usually means movement, not a bad tile job.
- Tub-to-tile line: this should be caulked, not grouted.
- Counter-to-backsplash line: a gap here lets water from the sink run behind the counter.
- Old caulk that's moldy or pulling away: don't caulk over it. It has to come out first. More on that in Why Does My Shower Caulk Keep Cracking or Turning Black?
If someone quotes you to re-grout every corner, ask them why those joints shouldn't be caulked. I wrote about what a good quote should look like in Why a Good Handyman Quote Starts With Photos. If you're choosing grout for the flat runs between tiles, see Choosing the Right Grout.
What it costs
A tub or shower area is $180, or +$90 as an add-on. A kitchen sink or backsplash is $180, or +$90 as an add-on, and a bathroom sink or backsplash is $180, or +$60 as an add-on. That's old caulk out, cleaned, and fresh 100% silicone. Prices shown are labor only. Caulking typically has a materials cost of about $15 per visit, depending on the product used, which is added to your final quote. See shower recaulking, sink and counter caulking and my pricing page.
Send me a photo of the corner
Text a photo of the cracked corner or the backsplash line, plus your ZIP code. I'll tell you if it's a caulk joint and what the next step looks like.
Call or text (619) 815-7588.