Judman;
Good afternoon, I hope it's cooled off a bit in your part of the world and you and your fine family are well.
The hardy plank we used up here was always primed when it came from the factory.
Usually you should not have to prime a quality paint again, but a light sanding after a good wash can't hurt anything as it'll loosen off any residual scale and give a wee bit more surface.
As far as paint types available south of the medicine line, sorry, I'm not sure what is available.
Ours up here has pretty much all gone to latex based, but the better stuff - which means $50-$60/4 liters - applies nicely, sticks well and seems to last quite well in the Okanagan sun.
I've used Behr, Sico and Olympic in the last few years up here and been happy with the result, but again am not sure what you folks have down there.
Hope that was useful to you or someone out there.
Good luck with the project and all the best.
Dwayne
