On Oct 25, 6:30 pm, Manster wrote:
Mikepier wrote:
Then glue and screw the plywood to the joists, followed by 1/4"
Hardibacker over that plywood.

I figured it would better to put 3/4" plywood rather than 1/2" plywood
plus 1/4" hardibacker, right or wrong?

I suggest the 3/4" ply + the Hardibacker. With the plywood there's
chance of flexing, the backerboard adds density which helps to eliminate
flex problems. You'll sleep better. :-)

I posted this link the other day. It's a short but IMHO extremely
important read. Check it out.http://www.ttmac.com/deflection_limitations.htm


I can only go 3/4" high due to height problem matching existing floor.
So whats better?
A) 3/4" plywood,
B) 1/2" ply plus 1/4" backer
C) 1/4" ply plus 1/2" backer