I’m gutting an old bathroom, down to the joists/studs. Based on what they did in the 20’s/30’s, I’ll be sistering the joists. I’d like to get as even of a transaction between floor and tile and want to figure out the ideal sistering height.
Is there an average thickness that I should account for when accounting for a tile floor, including subfloor. My thought was to go with Ditra and my current estimates come out to @ 1 1/8″ with a 3/4 Plywood subfloor.
Does this sound correct?
Thanks,
JNF
p.s. follow on question. When I pulled up the old tile floor, there was this bizzare subflooring that was a mixture of sand/rubble and lava rock. Any reason they used lava rock, back in the day?
Replies
I'm not sure why you intend to sister in joists at different heights...but as far as tile is concerned...Ditra is waffel shaped dimpled plastic, and I believe the dimples rise no more than 1/4 inch above the floor...perhaps even slightly less.
Ceramic tile can be varied in thickness depending on what type you purchase... usually anywhere from 1/4 inch to 3/8ths and sometimes up to 1/2 inch in thickness. It would be best for you to get a sample piece of what you intend to install and then figure and frame accordingly.
Adding 3/4 for plywood subfloor, plus 1/4 for ditra and another 1/4 for tile thickness, I get a nominal total thickness of 1-1/4.....HOWEVER, don't forget to add in the thickness of the tile adhesive (thinset) which for large floor tile will probably add another 1/4 inch or so to the overall final floor thickness. Adding in the thinset puts this figure at 1-1/2 inches overall.
Best advice I can give you is,..... if floor heights are critical to your game plan, obtain samples of ditra and the tile that you plan to use and ask the tile salesman what type of adhesive to use with this tile and find out the amount needed to properly embedd the tile. With this knowledge, you will have a very good idea of your overall finished floor height.
BTW, Home Depot is now stocking Ditra ( at most store locations) and you can get samples of this product from them.
Davo
I agree with Davo ... get samples of the actual tile you plan to use. Otherwise you're taking a chance and could be wasting time, monbey and material.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I'd say buy all that you will need now. You have to buy it sometime, and if it is hand, it can't go out of stock.