Ah so! Thanks. What is underlayment?

"Robert Allison" wrote in message news:R7rSi.602$od4.301@trnddc04...
Sammy bin Snoozin wrote:

What's the best way to do this? Below is from Eric Gurney 7/21/2000 which is the best I could find with google...

From http://www.custombuildingproducts.co...derBoard12.htm
(link no longer good)

Fasteners: Galvanized roofing nails, 1 1/2" (38 mm) long with hot-dipped
galvanized coating for use with wood framing. Nails should meet Federal
Specification #FF-N105B/type 2 style 20. Custom Concrete Backerboard Screws
or equivalent, 1 1/4" (32 mm) long, for use with wood or 20 gauge steel
framing.

Underlayment: Using a 1/4" (6 mm) square-notched trowel, apply a setting bed
of latex-modified mortar to the subfloor or base. Immediately laminate 1/2"
WonderBoard Concrete Backerboard 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" (1.2 - 5.1 cm) of edge. Fill all
joints and corners solid with latex-modified mortar. Taping of floor and
counter joints is not required.

Sam

If you are trying to fasten wonderboard directly to floor
joists, then there is your problem. The reason that you can
find no instructions on how to do it, is because you cannot do
it. Wonderboard cannot bridge floor joists, so you must have
and underlayment to support it. Then you fasten the
wonderboard to the underlayment.


--
Robert Allison
Rimshot, Inc.
Georgetown, TX