There is nothing between the plywood and the joist. In my case the DIY
book I have (Ceramic Tile by Creative Homeowner sold at my local Big
Box store) it's clear the reference is for the total thickness of
subfloor and underlayment. Whether or not the book is right is open
for debate, but your jump test seems like a good idea either way.
Again and for the record, I won't be using 3/8, I'll be using 5/16 but
I think your point is the same. Thanks for your thoughts.
Try this site for your question: www.johnbridge.com
- posted on November 1, 2005, 1:19 pm
You'd better double check what your book says. I'm pretty sure the
NAtional Standards for ceramic tile require 1 1/8" thickness of
subfloor (i.e. plywood) to prevent any movement. Even 1/2" Hardibacker
doesn't provide any significant structural support, so including it in
the 1 1/8" could lead to cracked tiles down the road. Since you have
space restrictions you could make the floor stronger by adding 2x6
supports perpendicular between the joists. And do apply thinset under
the backer board for added stability.
- posted on November 4, 2005, 10:54 am
I have checked my book. It not only states 1 1/8" total thickness but
even shows it in an illustration. Perhpas I'm confusing terms and
that's getting me into trouble. My understanding is that the SUBFLOOR
and the UNDERLAYMENT together must be at least 1 1/8". I thought the
backerboard counted as underlayment. If it does not then that's where
I'm wrong. Can anybody clear this up for me?
Here's Home time's definition of the 1 1/8" which again seems to
suggest 1 1/8" total including the backerboard which they (further
down) describe as underlayment.