Replies

1. 
   Guest_ | Jan 29, 2000 07:16am | #1

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   Assuming your backerboard is secured firmly in place, I'd say you probably had used too much thinset and/or the thinset was too "loose". For marble tile, movement of even 1/16" out of plane is too much, so put away the trowel and backbutter the tiles with a stiffer mix.

   Backbuttering is actually a two stage process. One, skim coat the tile to "ground" the thinset to the tile; two, build up the thinset so it will a)be enough to allow exact placement of the tile, b)be adequate for 100% coverage (for marble).

   Just be glad it was you who had the close call and not your customer.

1. 
   Guest_ | Jan 30, 2000 06:32pm | #3

   *Like Rich said I'd backbutter those large tiles. The only thing I do in addition to backbuttering when setting a ceiling with larger size tile is to put a very thin coat of thinset on the backerboard with the flat side of the trowel first. Really push it hard into the surface. I think this helps the tile "grab on". Good Luck.Dave

2. 
   james_murphy | Jan 30, 2000 06:32pm | #2

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   i had a close call with a 12x12 marble tile falling about 10 minutes after installation. i completed the job 3 tiles at a time using "deadmen" of 2x4
   to hold overnight.i was using thinset and additive over cement backerboard.
   any tips? trowel sizes ? buttered or trowelled?