I'd appreciate any opinions on what I should use to fill nail holes and dings on exterior Hardie Board siding. Thanks.

Bondo for the dings, and Alex 230 caulking then wiped down with damp sponge for the nail holes.

With any siding, you can get proactive to prevent damage.

The main culprit for damage to any siding is maintenance items: riding/push lawn mowers, weed-eaters, etc. If you place landscaping or equivalent to prevent cutting devices from slamming into sides/corners/etc. done. Another thing you can do is put a 30-45 degree slope on all of the non-butted corner trim boards to where "anything" will have a tendency slipe off and not catch like a 90-flush cut.

Finally, make sure your nail-gun pressure is set to where you are not sinking the nails too deep...deeper holes require more filler and when the caulk dries and the O2 leaves, it sinks leaving a depression...fill deeper nail holes 2-3 diff times allowing drying in-between applications.

Good luck,
tstex

This message has been edited. Last edited by: tstex,

Great suggestions, thank you for all the help.

We used some sort of porous material when we had to fill the wholes in the walls to install our bathroom vanity modern furniture. It wasn't that difficult neither, I should check to see how was that material called.