I had already posed the same question to Alan from Quillan, who is working on Nigel's place in Leran. So far, everyone was in agreement. It wasn't an ideal situation, but they all used "greenboard", or water-resistant drywall. And, thus far, knock on tile, they had never had a problem with tiles falling off. But, they said I should talk to the real expert---John the Aussie. Over lunch at Le Rendezvous after the walk, I captured John's attention and asked my question. Sally overheard me, apparently couldn't believe I was still dwelling on this trivial matter, and suggested that I 'get a life.' At the risk of sounding obsessed, I pressed on. John reduced things to their most simplistic form: "It's not rocket science".
So, what was my problem? Am I a tiling prima donna, a skeptic or someone harboring a bizarre neurosis of 'fear of falling tiles'? I searched for answers in my tiling books and, of course, the Internet. Some of the tiling guru websites weren't reassuring, confirming my gut-level fear that "all greenboard should be torn down "! When I dreamed that night about tiles falling off the walls like giant raindrops, I knew I needed a different direction. I scoured the catalogs from Tout Faire, Chausson, Mr. Bricolage, La Peyere and BricoMarche, looking for something......
Then we happened to be in a carrelage magasin (tile store) and they had a display of Wedi board---a waterproof tile underlayment. Parfait! Different thicknesses, depending upon what it's going over, a foam-core sandwich board encased with thin layers of fiber cement. It's much lighter than the US cement board, which makes transporting it up three floors much easier. The board itself was somewhat expensive, but the mastic, waterproof seam tape and screw kits were killers. Screws are screws, aren't they?
Now I'm having another nightmare. If the tiles fall off now, what can I possibly blame it on?