# How much thickness will thinset add?



## Ron6519 (Mar 28, 2007)

Kiwi. said:


> I'm doing tile in our laundry and its going to meet the existing wood floor in our kitchen. If add a layer of thinset (to the ply sub-floor), then backer board, then another layer of thinset, then tile, how much thickness will those two layers of thinset add?
> 
> I'm trying to get the transition from the tile to the wood floor to be level as possible and am debating between using 1/2 inch and 1/4 inch backer.
> 
> ...


What thickness of plywood is on the floor now? You need to increase the floors rigidity to keep the tile from cracking. That usually requires another layer of ply to get it up to at least 1". 
Ron


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## JazMan (Feb 17, 2007)

> How much thickness will thinset add?


The thin set under the backer board may account for about 1/16". The bond coat for the tiles about 3/32 - 1/8". Your best bet is to use 1/4" which should end up being 5/16", standard thickness tiles can average about 3/8" installed, plus or minus. You'll be very close, but may need to tweak the last tiles a bit.

Although the more plywood the better, the industry minimum standard calls for 5/8" subfloor or thicker. 5/8" scares me, but 3/4" plywood subfloor has been proven for many years to work well as the subfloor for ceramic tile installations. 

Have you consulted a span chart to see if your framing system is stiff enough for tile installation?

Jaz


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