Installation Instructions
Wall 
Sheathing
1905 W. Haskel Street, Appleton, WI 54914
www.appletonsupply.com• 800-558-3414
Fiber Cement/Smart Side Best Practices
3/16 INCH GAP ON
BUTT JOINTS
3⁄16
The “No Caulk” Solution
Appleton Back Flash is 
designed for use behind siding 
butt joints. Back Flash directs 
water away from the structure 
protecting against moisture 
intrusion. 
Back Flash is made from 
aluminum, so it will not rust. 
Seam Backer Plates are 
considered best practice by
all major fiber cement siding 
manufacturers.
ALUMINUM SEAM 
BACKER PLATE
Stud
1" from top
3/8" from 
edge
House
wrap
MINIMUM 2" CLEARANCE
Aluminum Angle Flashing 
protects siding against 
2nd story wall to 1 story 
roof and chimney to roof 
connections. Allows 
siding to be installed the 
recommended 2" above 
the roofing, deck, paved 
driveway or sidewalk.
House 
wrap
House 
wrap
2" Min.
Exterior Slab/Roof Deck
Wall 
Sheathing
4" HIGH KICKOUT
FLASHING
Appleton Kickout Flashing is a 
pre-formed flashing used to divert 
water away from a wall and into a 
gutter. Usually installed on the 
bottom of a roof edge that 
intersects a wall surface.
When properly installed, it will 
provide added protection against 
the penetration of water into the 
building envelope. 
4" Min.
1/4" Gap
DO NOT CAULK
Stud
Sheathing
Fiber Cement siding manufac-
turers are now recommending 
that butt joints not be filled with 
caulk. Aluminum seam covers 
are the most attractive alterna-
tive. H-Moulding joint covers 
protect butt joints and elegantly 
provide an expansion joint to 
help prevent buckling or 
distortion.
Z-FLASHING
Aluminum Z-Flashing 
protects top edge of panel 
siding from water infiltra-
tion. Protects top edge of 
lap siding below band 
board or when transitioning 
to another style siding on a 
gable end.
1/4"
3/8"
1 1/8"
DRIP CAP
Directs water away from 
the structure above doors 
and windows.
Installs at the top of trim 
boards to protect against 
moisture intrusion.
1/4" Gap
DO NOT CAULK
Insufficient Clearance: Fiber Cement siding requires 6" of clearance from 
the siding to the finished grade, and 1" clearance to shingles.
Fiber Cement siding requires an uncaulked 3/8" gap above windows and 
other similar penetrations, protected by Drip Cap flashing
Kickout flashing is a piece of metal at a roof end that prevents water from 
leaking into the wall. The flashing must have a 4" upper leg.
Joint Treatments
To keep water out of the butt joints H-Mold joint covers should be installed, 
backed by a 6" wide piece of Back Flash™. The butted ends of the siding 
should be factory finished or sealed with paint.

