I have read comments that scoring hardie board siding does not make for
a good cut, but I have found that for cross-cutting, scoring by far
makes the straightest, cleanest edge. The secret is to score it several
times on each side using a utility knife. To break the board after
scoring, just bend the shorter side up, unless it is very short, in
which case a sharp rap with a hammer usually does it. Then, take a few
strokes with a rasp to clean up any debris left hanging on the edge.
No muss, no fuss, and - no dust! Otherwise, a circular saw with a
hardi-blade will work, but it generates sufficient dust to obscure any
marking you are trying to follow. The utility knife blades do wear so
have plenty of spares.
For long diagonal cuts this method doesn't work as the board wants to
break cross-wise, so a mechanized shear is the best. The
"Whipper-Snapper" shear is great because it will also let you make
medium radius curved cuts suitable for electrical lighting fixtures,
etc. For small details a small portable sabre saw with a tungsten
carbide blade worked the best. Finally, for ripping, a diamond
hardi-blade in my table saw worked very nicely - just make sure you are
up-wind, or wear a dust mask.
For setting the siding in place, I used two or three loops of ~1"
wide straps marked 1 1/4" up from the bottom. Screw the straps to the
wall with the marks at the top of the previous course, and slip your
siding in. For attaching the siding, cement board screws (Grabber and
Marker are two brands) worked very well for me - no need to lug a
nailer up ladders, just a small battery powered drill/driver. Plus you
can back out the screws to release the mounting straps.
I used pre-painted hardi-board and had the local hardware store mix
paint to match. I got the Create-a-Color caulk kit from Red Devil and
used the paint to make matching caulk.
The neighbors say the job looks good and I am happy with it as well.