Guy's
Had a look at a job today, it's a ground floor bathroom, floor has been laid
with 18mm ply on 6"x2" joists @ 200mm centres. they want to lay marble tiles, approx 300mm square. Because of any potential movement in the floor, would you recommend using a de-coupling mat, say Ditra for instance.

Your thoughts,

John

use ditra or same as. flexi adhesive to stick down ditra and tiles . oh and donot forget sbr prime wood floor befor you start.

As long as the deflection is minimal then a un-coupler will cope with the lateral stress from expansion issues.

Originally Posted by paul flight

use ditra or same as. flexi adhesive to stick down ditra and tiles . oh and donot forget sbr prime wood floor befor you start.

Only if adhesive manufacturer recommends it

As Dave, Ditra, Dural etc only help with lateral movement. Not deflection Marble is a soft material, zero deflection is a must imo

Thanks guy's for the above advice, one more thing, what's the minimum gap between tiles for grouting?

Regards,

John

2mm on concrete and 3mm on other substrates for me