Grout, Caulk, or Silicone? Why Your Shower Corners Keep Cracking., by Wade Harlan on YouTube. 12 min 43 s.
- Video length
- 12 min 43 s
- Time to do it
- 2 hours
- Difficulty
- Medium
- Steps
- 8
What you need
Steps
Press on the tiles around the cracked corner. If they sound hollow or move, stop and have a licensed tile contractor or plumber look at it before you seal anything.
Check whether the tub or shower pan flexes when you stand in it. A moving base breaks the sealant joint again and again, so fix the support first.
Look outside the shower for stains or soft drywall. Water damage behind the wall means the repair is bigger than a new bead of sealant.
Cut out the old grout or caulk along the inside corner with a grout saw or utility knife. Work carefully and wear safety glasses, since sharp tools slip easily.
Scrape the joint clean down to the tile edges and vacuum out the dust. Wipe the surfaces with denatured alcohol and let them dry fully.
Push backer rod into deep gaps so the sealant sits at about half the joint width. Silicone needs a proper shape to stretch without tearing.
Run painter's tape along both sides of the joint. Fill the corner with 100% silicone sealant, not grout and not siliconized acrylic caulk.
Tool the bead smooth with a wet finger or silicone tool, then pull the tape while the sealant is still wet. Let it cure as the tube label says, usually 24 hours, before water hits it.
Tips and common mistakes
Grout is rigid and cracks at changes of plane, so inside corners need a flexible sealant instead.
Siliconized acrylic caulk has low movement tolerance and often peels in wet shower corners.
Keep the sealant bead thin and even so it can stretch when the tub or walls move.
Do not caulk over old sealant or wet surfaces, since the new bead will not bond.
Questions
Should I use grout or silicone in a shower corner?
Use 100% silicone sealant rated ASTM C920. Grout is rigid and cracks where two surfaces meet, and acrylic caulk stretches too little for a wet corner.
How long before I can use the shower?
Wait at least 24 hours after applying silicone, or longer if the label says so. Water too soon ruins the bond and the crack returns.
What if the crack keeps coming back after resealing?
Look for a moving tub, loose tiles or water damage behind the wall. Those need a licensed contractor, not another tube of sealant.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
