"Colbyt" wrote in message
...

"Andy S" wrote in message
...
You were right Colbyt...I'm back.

Thanks everyone with the suggestions for changing of valves. It was
actually fairly simple, the new valve fit perfectly with the existing
pipe
inlets with the inlets being threaded couplers. No leaks first time
around!

Anyhow, while finishing up the taping of the Wonderboard around the
bath/shower walls, I found rotten particle board around the base of the
tub.
The sub-floor is in good shape but, of course, I am having to replace
the
bad portions of particle board. Is there anything wrong with me
replacing
the bad particle board with 1/2' Wonderboard? I'm also going to tile
the
floor so I'm going to place on top of everything 1/4' Wonderboard (after
tearing off 3 layers of *poor* quality linoleum to help with floor
height
issues).

Thanks again!


I would bite the bullet now and get all the particle board out of the
bathroom. I can't think of any reason other than cost that you could not
use 2 layers of wonderboard. I have found the hardiebacker product to be
a
tad easier to work with than wonderboard.


Colbyt



Wonderboard has no structural value for floors. It is a decoupling system
for tile installations. It must have a subfloorunder it.... From the
manufacturer-

Subfloor Requirements: 5/8" (16 mm) exterior grade plywood
or OSB panels (PRP-108) should be securely glued and fastened
to floor joists. Floor joists framing should be spaced a maximum
of 16" (40.6 cm) o.c. 3/4" (19 mm) exterior grade plywood or OSB
subfloor framed with I-joists spaced a maximum of 19.2"
(48.7 cm) o.c. or I-joists or truss system spaced a maximum of
24" (61 cm) o.c. are also acceptable. When setting dimensional
stone larger than 12" x 12" (30 cm x 30 cm), a 3/4" (19 mm)
subfloor must be used for all installations. All plywood or OSB
subfloor sheets must be gapped 1/8" (3 mm).
Installation: Using a 1/4" (6 mm) square-notch trowel, apply a
setting bed of latex-modified mortar to the subfloor or base.
Immediately laminate 1/2" WonderBoard to subfloor base,
leaving a 1/8" - 3/16" (3 - 5 mm) space between boards at all
joints and corners. Stagger joints so they do not line up with
underlying substrate joints. Fasten backerboard every 6" - 8"
(15.2 - 20.3 cm) o.c. throughout board field and around all
edges while setting bed mortar is still workable. Around
perimeter of each board, locate fasteners within 1/2" - 2"
(1.3 - 5 cm) of edge. Fill all joints and corners solid with latexmodified
mortar. Taping of floor joints are not required.