Custom Building Products, a tile maker, puts caulk in the changes of plane, where settling or movement is possible: where a countertop meets the backsplash, tile meets the tub, or wall meets floor. Grout goes in first.
Where caulk goes, by the tile makers
- Custom Building Products says caulk is flexible, so it can withstand structural movement at those joints without cracking.
- NTCA’s TileLetter magazine adds the perimeters, where tile meets walls, other floor finishes, curbs, columns, pipes or ceilings, and the inside corners indoors (inside and outside corners outdoors). It says the best material there is a flexible sealant that meets ASTM C920.
- TEC (H.B. Fuller) writes in a sponsored TileLetter article that if a shower has no movement joint where the wall meets the floor, the grout will crack, because each plane moves on its own.
TileLetter’s answer on looks is plain: a silicone joint is much nicer to look at than a hard grouted joint that cracked when the wall and countertop settled and shifted.
What tile makers sell for those joints
| Product | Type | Where | Limits |
|---|---|---|---|
| Custom Building Products Ceramic Tile Caulk | Siliconized acrylic, sanded or non-sanded | Around sinks, tubs and showers, and where tile meets tile or another surface | Interior only; not for constant water; joints up to 1/4 inch; 24 hours before water |
| Custom Building Products Commercial 100% Silicone | 100% silicone | Coves, corners, changes in plane and expansion joints, inside or out; pools and wet areas | Up to 1 inch wide and 1/2 inch deep; after the grout cures; not paintable |
| LATICRETE LATASIL | 100% silicone, neutral cure | Tile and stone joints, expansion joints, pools and wet areas | 1/8 to 1 inch wide; sealant 4 days before submersion, grout and mortar 14 days; can’t be painted |
| Schluter DILEX-EKE | Corner profile with a soft 3/16 inch movement zone | Floor-to-wall transitions and inside wall corners | Grout or setting material fills the joints beside it |
From each maker’s own page or data sheet.
Order of work
- Grout first. Custom Building Products says its silicone goes in after the grout has cured, and GE’s backsplash guide says to wait 24 to 48 hours after grouting (its FAQ says at least 24 hours).
- A clean, dry joint. Custom Building Products says its caulk always goes into a dry joint, and Chip O’Rear of Custom Building Products writes in TileLetter that thinset must be raked out of a movement joint when setting the tile.
- Color: the Custom Building Products tile caulk comes sanded or non-sanded to match grout texture, and LATASIL matches all 40 LATICRETE grout colors.
- Stone: Custom Building Products says staining may still occur and to test, and LATICRETE says to do a test area with stone.
We wouldn’t run caulk over the grout lines between tiles. One GE article suggests sealant along grout lines, but the tile makers we read keep sealant to the corners, edges and movement joints.
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