Quick question…
I’m grouting my shower this weekend. 3×6 subway tile on an acrylic base that was set in mortar. Hardibacker with liquid membrane. Unsanded grout with a matching unsanded caulk.
I’ve learned that because of possible cracking, you want to caulk instead of grout at any change of plane.
Does it hurt to only fill those joints 1/2 way with grout to act as a caulking backer? Am I better off using backer rod or making multiple passes (after appropriate set up times)?
Do I caulk where the bottom tiles meet the shower pan, or leave open? I’ve heard some say to leave open for drainage. I don’t understand how any water behind the tile would be able to drain down to the bottom.
Thanks for your help, and have a great weekend!
Replies
"Does it hurt to only fill those joints 1/2 way with grout to act as a caulking backer? Am I better off using backer rod or making multiple passes (after appropriate set up times)?"
If your joints are this big, then they're too big for unsanded grout.
Thanks for the reply.
I guess the multi-pass/backer rod question was more aimed at the tile/shower pan joint where it’s more deep than wide.
Grout lines were made with 1/16” horseshoe shims.
Either use backer or caulk. Don't use grout in this situation. Something I'm doing more and more now is masking before caulking.
Thank you
X,
The main purpose for using backer rod is to limit the contact of the caulk to only two sides of a gap. Add a non moving contact point at the back and risk it separating what you wish to seal.