Use Hardie Plank for Soffit on New Cornice

Learn how to use Hardie Plank for soffit on new cornice with this free and easy guide. Follows manufacturer’s recommended installation procedures for both vented and solid panels. The advantages for using fiber cement panels on the exterior of a house include

  • rot resistant
  • insect resistant
  • already primed
  • great aesthetics
  • durable

Check the Framing

The whole process begins with a quality sub-structure. This includes a 2 x 4 against the wall, blocks every 16″, and a sub-fascia. It is important for it to be very straight and level. If there are imperfections in the framing, then it should be straightened up. Accomplish this by stretching a line from end to end on the outside edge of the sub-fascia. Make sure it is parallel with the wall. If it is 12″ wide one end, then it should be 12″ wide one the other. Whatever it takes to make the sub-fascia close to the line, do it.

How to Saw Hardie Plank Soffit

It is recommended by the manufacturer to use a special blade on a circular saw to cut the panels. I find that is it is just as good to use an old framing blade. It will last quite a while. Always use sawhorses set up with a cutting board; a 2 x 12 x 12′ works best but just about anything will work. The saw should be set to penetrate the soffit and into the cutting board about 1/4″. This helps to stabilize the saw and makes for straighter cuts. Always watch the blade and keep two hands on the saw.

The sawhorses should be at a location where the saw man can see the nailers. They should never be overstocked with material. It is important to keep them mobile. Remember to always handle Hardie Plank products on edge and to use the buddy system whenever possible. Do not drive any nails into the cutting board; it would quickly render a blade useless.


It is important to note that the dust created when sawing fiber cement panels is harmful and should not be inhaled. Set up the sawhorses outside. Use the wind to your advantage if possible. I find it pretty easy to simply hold my breath while making cross cuts. It is a different story when doing rips. It is advisable to use an approved breathing filter to avoid complications with breathing that could result from inhaling the dust created by sawing fiber cement panels with a circular saw. Never saw this type of material inside.

How to Nail

The best way to nail fiber cement soffit is to use a coil nailer such as the Bostich N66C. If  you prefer to hand drive the nails, then be prepared for a different nailing technique. It is much more difficult driving nails straight up. It would be advised not to attempt it unless you have plenty of nailing experience.

Other Notes

  • Use solid in the gables and vented everywhere else; its that simple.
  • Be sure to turn the perforations in vented pieces to the outside.
  • Use a drill with a hole saw for any flood lights or other electrical openings.
  • It works better to use a small piece of solid soffit where any light fixtures are going.
  • Use MiraTec or other treated exterior trim to compliment the fiber cement soffit.

Hardie Plank works well for siding as well as soffit.