I have had oak awaiting installation on my existing stairway for well over a year and will soon get to putting it in. The "experts" gave me (supposedly) all the necessary materials BUT I only have 1 10 inch x 8 foot board for a skirt. This will only be enough to skirt one side. Should I skirt the inside (already has a wall above the stairs) or the outside (railing on this side with wall below the stairway). Is there a preferred way for a single skirt?
You really need another skirt board for the wall. When I have my druthers, I make the skirt board the same thickness as the base that will meet it at the top and bottom so it ties in continuously. If need be, I rip a base so the top element, if it has a profile, will make it look like the base goes right up the wall along with the treads.
As a mention, the material you have for the skirtboard would be used on the outside where the wall is under the staircase, using riser brackets to help hide some of the joinery.