What It Means
Grout and caulkCaulkingSealing cracks and gaps between parts of a house that don't move, such as around window and door frames, with a flexible filler called caulk. See more both fill the gaps in tile work, but they belong in different joints. Grout, usually cement-based, fills the joints between tiles lying on the same flat surface. Caulk, a flexible sealant such as 100% silicone, goes where two surfaces meet at an angle or where the two can shift slightly against each other, such as an inside corner or the line where tile meets a bathtub. Tile makers call those spots movement joints.
Try It: Grout or Caulk for This Joint?
Pick a joint in a tiled bathroom or kitchen to see which material the tile makers put there.
Joints between tiles on one flat surface.
Corners, changes of plane and edges that can move.
Grout. The tiles sit on the same plane, so a rigid fill works.
Caulk. It's a change of plane, and Custom Building Products says those joints need a flexible sealant; LATICRETE recommends 100% silicone at a tub or shower.
How It Sounds at Home
- "The grout in the corner keeps cracking."
- "That line along the tub should be caulk, not grout."
- "Get the silicone, not the sanded grout."
The Breakdown
Side by side
| Grout | Caulk (flexible sealant) | |
|---|---|---|
| What it is | A rigid, usually cement-based fill | A flexible sealant, often 100% silicone in wet areas |
| Where it goes | Joints between tiles on the same flat surface | Changes of plane, inside corners, where tile meets a tub, shower or countertop |
| Handles movement | No | Yes, the small shifts between surfaces are its job |
| Upkeep | Clean regularly; seal when makers' water drop test says so, about every year or two | Replace when it cracks, peels or pulls away (Buhata's own suggestion) |
Why the difference matters. Custom Building Products calls for flexible movement joints at every change of plane. If the wrong material fills one of those joints, stress from the surfaces shifting can crack the grout, crack tiles or loosen them.
Pick grout if the joint runs between two tiles lying flat on the same wall or floor.
Pick caulk if the joint is a corner, a change of plane, or the edge where tile meets another material, like a tub, shower or countertop. LATICRETE recommends 100% silicone caulk around a shower or bathtub next to tile or stone.
Good to Know
Buhata's own pages on grout sealingGrout sealingBrushing or rolling a sealer onto grout lines so they soak up less water and fewer stains. Makers suggest resealing about every year or two. See more, grout cleaningGrout cleaningScrubbing the lines of grout between tiles with a brush and cleaner to lift dirt, soap film and mildew stains. See more and caulking go further on upkeep. New cement grout needs to cure before it's sealed; Mapei puts that at 24 to 72 hours minimum, depending on the grout maker's instructions. Don't caulk over moldMoldA fungus that grows indoors wherever moisture lingers. EPA says fix the water problem, then scrub it off hard surfaces with detergent and water. See more: EPA says to clean hard surfaces with detergent and water and dry them first, as the mold page explains. Match the caulk to the spot by its label, since a tub joint and an exterior window joint call for different products.
FAQ
Should the corners of a shower be grouted or caulked?
Caulked. Corners are changes of plane, and Custom Building Products says flexible movement joints belong at every change of plane. Grout there can crack when the surfaces shift.
Do you caulk or grout where tile meets the tub?
Caulk. LATICRETE recommends 100% silicone caulk around a shower or bathtub where it meets tile or stone.
Can I put caulk over cracked grout?
On a flat run of tile, no: that joint takes grout, so regrout it. If the cracked grout sits in a corner or along a tub, the joint calls for a flexible sealant instead, and Buhata's own suggestion is to take the old grout out first so the caulk has a clean joint to bond to.
Do It in Buhata
Maintenance and Tasks with a repeat
Add "Check tub and shower caulk" to Maintenance in your Household X add-on each season, so it rolls forward each time you tick it.
Open BuhataRelated Terms and Categories
- Grout sealing
Brushing or rolling a sealer onto grout lines so they soak up less water and fewer stains. Makers suggest resealing about every year or two.
- Grout cleaning
Scrubbing the lines of grout between tiles with a brush and cleaner to lift dirt, soap film and mildew stains.
- Caulking
Sealing cracks and gaps between parts of a house that don't move, such as around window and door frames, with a flexible filler called caulk.
- Mildew
A flat, usually gray or white mold that grows on damp surfaces such as shower grout, curtains and fabric left wet.
- Mold
A fungus that grows indoors wherever moisture lingers. EPA says fix the water problem, then scrub it off hard surfaces with detergent and water.
- Bathroom deep clean
A top-to-bottom bathroom cleaning that reaches grout, tub, toilet, floor and fixtures. The ACI's routine puts it every two weeks.
Sources
Custom Building Products, "Movement Joint in Tile Assemblies" (WP104); Custom Building Products, "Silicone Caulk Is Rated for Expansion Joints in Traffic Areas" (TB41); LATICRETE, "Choosing The Right Caulk for Showers & Bathtub"
- www.custombuildingproducts.com/media/736042/movement_joints_wp104.pdf
- www.custombuildingproducts.com/media/686994/tb41_ccsc.pdf
- www.laticrete.com/blog/2024/june/using-the-right-caulk-for-the-job
Last updated .