When setting up tile overhead, make sure the substrate is solid and stiff, and that it provides an excellent bond. Cementboard installed over beefed-up framing will not droop.
I’d prefer to extend marble wall tiles up to and across the ceiling of a walk-in shower. We plan to use a Kerdi decoupling membrane layer over 1/2-in. mold-resistant drywall.
Just what do i have to know about putting in marble tile on a roof? Should I use thinset, or would mastic become better option? Must I tighten up the joist spacing?
Justin Fink, Glastonbury, CT
Tom Meehan, owner of Cape Cod Tile Works in western Harwich, Mass., replies: years ago, an item of limestone tile fell from a roof onto my mind two days before we showed up on a panel at a trade tv show with other tile specialist Michael Byrne. We were left with nine stitches in my own forehead and two black colored eyes. Michael then ribbed myself at subsequent shows, saying, “i did son’t recognize you minus the black colored eyes.”
Since that incident, I have used cementboard as a tilebacking substrate because it provides a tenacious bond. It's a great idea to stiffen the ceiling framing before the cementboard is set up because if the ceiling can flex, a tile could fall.
I mightn’t make use of membrane layer regarding ceiling. Tile should be bonded directly to the cementboard with a good latex-modified thinset cement (definitely not mastic) such as TEC Superflex ( Laticrete 333 ( or Mapei Ultraflex 2 ( Mix the thinset with a mixer rather than by hand, let it slake for five minutes, and then mix it again.
In the event that thinset is combined completely really and has now good tack to it, the marble tiles will stay in place, but never ever trust a ceiling-tile bond before following day. Don’t turn your back on pieces or work under the pieces that you’ve set up. For big ceilings, I usually do 50 % of the ceiling at the same time and work my solution the entranceway. 24 hours later, when the tiles tend to be set, i actually do the remainder ceiling.