Instructions / Assembly

9
Description
PermaBase BRAND Flex
®
Cement
Board is a polymer-modified
cement board reinforced with an
alkali-resistant fiber mesh ideal for
use around ceilings, beams,
columns, arches and archways,
walls and anywhere an evenly
curved surface is required.
Applications
䡵 Radius wall and ceiling
construction
䡵 Exterior and interior columns
䡵 Radius shower walls
䡵 Radius tub step-ups
䡵 Saunas and steamrooms
Features/Benefits
䡵 6" (150 mm) minimum radius
for 90˚ corners.
䡵 Bends immediately, easily and
evenly without kerf cuts.
䡵 Easy installation, reduces skilled
labor costs.
䡵 Can be used for interior or
exterior applications.
䡵 Creates uniform curved surfaces.
Limitations
䡵 For convex surfaces, PermaBase
Flex must be applied with the
rough surface and tapered
edges exposed.
䡵 For concave surfaces, PermaBase
Flex must be applied with the
smooth surface exposed.
䡵 PermaBase Flex Cement Board
should not be used for fire-rated
assemblies.
䡵 Maximum framing spacing
should not exceed 8" o.c. and
must be designed to limit
deflection to less than L/360
under all live and dead loads.
䡵 Steel framing must be 20 gauge
or heavier.
䡵 PermaBase Flex Cement Board
is vapor permeable and unaf-
fected by water but is not a
water barrier. Consult local
building code for moisture
barrier requirements.
䡵 Do not use drywall nails, screws
or fiberglass mesh tape.
Installation
Wall Framing: Studs should be
spaced a maximum of 8" o.c.
Edges/ends of PermaBase Flex
parallel to framing should be
continuously supported. Provide
additional blocking when neces-
sary to permit proper PermaBase
Flex attachment. Do not install
PermaBase Flex directly over
protrusions from stud plane such
as heavy brackets or fastener heads.
Studs above a shower floor should
be either notched or furred to
accommodate the thickness of
the waterproof membrane or pan.
The surround opening for a tub or
precast shower receptor should
not be more than 1/4" longer than
unit to be installed.
Ceiling Framing: The deflection
of the complete ceiling assembly
due to dead load (including insula-
tion, PermaBase Flex, bonding
material and facing material)
should not exceed L/360. The dead
load applied to the ceiling frame
should not exceed 10 psf. Ceiling
joist or furring channel should not
exceed 8" o.c. Edges of PermaBase
Flex parallel to framing should be
continuously supported. Provide
additional blocking when neces-
sary to permit proper PermaBase
attachment.
PermaBase Flex Cement
Board:
Apply PermaBase Flex with
ends and edges closely butted but
not forced together. Stagger end
joints in successive courses. Drive
fasteners into field of cement
board first, working toward ends
and edges. Space fasteners
maximum 8" o.c. for walls, 6" o.c.
for ceilings with perimeter fasten-
ers at least 3/8" and less than
5/8" from ends and edges. Ensure
PermaBase Flex is tight to framing.
Joint reinforcement: Trowel
bonding material to completely fill
the tapered recessed board joints
and gaps between each panel. On
non-tapered joints apply a 6"
wide, approx. 1/16" thick coat of
bonding material over entire joint.
For all joints, immediately embed
2" alkali-resistant fiberglass mesh
tape fully into applied bonding
material and allow to cure. Same
bonding material should be
applied to corners, control joints,
trims or other accessories. Feather
bonding material over fasteners to
fully conceal.
Control Joints: For interior instal-
lations, allow a maximum of 30
lineal feet between control joints.
For exterior installations, allow a
maximum of 16 lineal feet between
control joints. (For exterior tile
applications, control joints should be
used a maximum of every 12'.)
A control joint must be installed
but not limited to the following
locations: where expansion joints
occur in the framing or building
(discontinue all cross furring
members located behind joint);
when boards abut dissimilar
materials; where framing material
PermaBase BRAND Flex
®
Cement Board
changes; at changes at building
shape or structural system; at each
story separation. Place control
joints at corners of window and
door openings, or follow specifica-
tions of architect.
General: All framing should
comply with local building code
requirements and be designed to
provide support with a maximum
allowable deflection of L/360
under all intended live (including
wind) and dead loads.
Sizes/Packaging
Thickness: 1/2" (12.7 mm)
Width: 4' (1219 mm)
Length: 8' (2438 mm)
Mass: 3.0 lb./ft. (14.6 kg/m)
Packaging: 30 boards per package.