Re: Tiling an uneven floor
all good points from houston.
i wont let my tile guy put down tiles on a floor thats has any less than 1 1/8" of substrate, meaning 3/4" floor sheathing then 3/8" underlay.
now if the house has old tongue and groove boards this is a different story, i will put down 1/2 if not 5/8" plywood for underlay and glue it down as well. reason being the old boards can make for an uneven floor which can telegraph though 3/8 plywood. just be sure to renail or screw down all the boards before putting the underlay down
fire up the saw and make some dust