USG Fiberock Underlayment and Tile Backerboard - Manual (Page 7)

Floor Application
Ceramic Tile
Underlayment or Tile Backerboard
Panel Application
Apply Type 1 organic adhesive
with 5/32" v-notched trowel,
latex-fortified mortar with
1/4" square-notched trowel.
Comb out adhesive or mortar in
straight, parallel rows (as shown
below) and immediately cover
with panel. Adhere panels to
subfloor, one panel at a time.
Fastening
Fasten to subfloor with 1-1/4"
D
urock
tile backer screws for
wood framing (or equivalent) or
1-1/2" hot-dipped galvanized
ring shank roofing nails spaced
8" o.c. in both directions with
perimeter fasteners at least 3/8"
and less than 5/8" from ends and
edges. Drive nails and screws so
that bottoms of heads are flush
with panel surface to ensure firm
panel contact with subfloor. Do
not overdrive fasteners.
Finishing Joints
F-119 Applying compound to Fiberock brand Panels
Fill joints with latex-fortified
mortar or Type 1 organic
adhesive and immediately
embed D
urock
tilebacker tape
or equivalent alkali-resistant,
fiberglass mesh joint tape.
Ceramic Tile Installation
Sweep all debris from
underlayment, and vacuum
carefully to eliminate dust
and dirt.
To set tile, apply latex-fortified
mortar or Type 1 organic
adhesive with a notched trowel.
Key in mortar or adhesive with flat
side of trowel to prime F
iberock
surface, then comb out adhesive
or mortar in straight parallel rows.
When combing out adhesive or
mortar, hold trowel at an angle to
maintain uniform thickness.
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