I am getting ready to side my home with Hardie Planks. When I Trim the doors on my back porch (covered aluminum porch with concrete slab) do I need to hold the trim board up 2"? If so, what suggestions do you have to fill that gap?
A threshold sitting level with a doors threshold is a sure way to get water under it and into the room inside.
Concider at least adding a Jamb sill under the door set in silicone.
Use vinyl brick moulding not wood. http://jamsill.com/