Installation Guide
16 in. O.C. maximum
Leave a minimum 1/8 in. gap between 
the siding and trim, then caulk. 
finish nailing
pattern
plywood or
OSB sheathing
water-resistive
barrier
1 in. from
ends
Figure 11
FACE NAILING REQUIREMENTS
Use 2 in. minimum 16 ga. finish nails to attach HardieTrim boards to wood frame construction. ET&F or equivalent fasteners or screws may be used to attach HardieTrim 
boards to steel frame construction.
Fastening instructions are similar for all applications. When using finish nails, position nails no closer than 1/2 in. from the edges of the trim and for all other fasteners no 
closer than 3/4 in. Fasteners must be no closer than 1 in. from ends of trim and spaced a maximum of 16 in. O.C. Ensure trim is adequately fastened.
James Hardie recommends using stainless steel finish nails when installing HardieTrim products.
Use a 2 in. finish nail to fasten trim together. Longer finish nails may bend.
Minimum fastener guide for finish nailing:
4 in.
6 in.
8 in.
12 in.
Site Built Corners
2 nails every 16 in.
3 nails every 16 in.
4 nails every 16 in.
Other areas (e.g. window 
trim, and band boards)
2 nails every 16 in.
3 nails every 16 in.
3 nails every 16 in.
Pre-built corner
1 nail every 16 in. to attach boards 
together + 1 nail every 16 in. each board
1 nail every 16 in. to attach boards 
together + 2 nails every 16 in. each board
-
-
*Follow all applicable codes when installing HardieTrim boards
PNEUMATIC FASTENING
James Hardie products can be hand nailed or fastened with a pneumatic tool. 
Pneumatic fastening is highly recommended. Set air pressure so that the 
fastener is driven snug with the surface of the siding. A flush mount 
attachment on the pneumatic tool is recommended. This will help control the 
depth the nail is driven. If setting the nail depth proves difficult, choose a 
setting that under drives the nail. (Drive under driven nails snug with a 
smooth faced hammer - Does not apply for installation to steel framing). 
DO NOT
STAPLE
do not
under
drive nails
do not
over drive
siding nails
Figure B
Siding Nail
Figure A
Finish Nail
Flush Snug Flush
Visit jameshardiepros.com for the most recent version.
TR1502_P3/9 09/19
HardieTrim
®
 Boards
GENERAL FASTENING REQUIREMENTS
Fasteners must be corrosion resistant, galvanized, or stainless steel. 
Electro-galvanized are acceptable but may exhibit premature corrosion. 
James Hardie recommends the use of quality, hot-dipped galvanized nails. 
James Hardie is not responsible for the corrosion resistance of fasteners. 
Stainless steel fasteners are recommended when installing James Hardie 
products near the ocean, large bodies of water, or in very humid climates.
Manufacturers of ACQ and CA preservative-treated wood recommend 
spacer materials or other physical barriers to prevent direct contact of ACQ 
or CA preservative-treated wood and aluminum products. Fasteners used 
to attach HardieTrim Tabs to preservative-treated wood shall be of hot 
dipped zinc-coated galvanized steel or stainless steel and in accordance to 
2009 IRC R317.3 or 2009 IBC 2304.9.5.”
Vertical trim may be installed
with a 1/4 in. min. clearance*.









