Originally Posted by CDNSr.
If i just have stringers--how do i make the top and bottom cuts of my skirtboards
It really depends on the type of stairs you have, does your stairs have an open side or walls on both sides. What will the top of the skirt tie into or die into. Are you trying to cut the bottom or top of the skirt so the top of the skirt is even with your base.
If the walls need to be painted, you can lay the skirt off on the wall to make it easier to cut and figure. Take your framing square and set down on the spacer between the wall and stringer. Make a mark at 12" even if the 1X12 isn't but 11 1/4", at the top of the stairs and again at the bottom of the stairs. Pop a line all the way from the floor through the two marks on the wall up past the last step.
Now you can see where the top of the skirt needs to be cut. If you want the bottom cut to be even with your base mold, just lay a piece of base mold at the bottom on the floor and make a mark where the top of the base intersects with the line you popped for the top for the skirt. Make a mark there. That is where you will want to make a plumb cut so the base will butt into the skirt.
Just a note here, if you plan to install a trim on top of the skirt which looks like the trim on top of you base mold be sure to drop the skirt down to allow for the mold to butt your base and run on up the skirt smoothly, it will look like the molding on to of your base just continues on up the skirt. Or you can just plumb up on your skirt a hair past the last nosing of the bottom tread and butt the base into the skirt there.
If just a straight run with no tie ins or you aren't trying to make the top flush with your base, set the 1X12 (usually) on edge on the treads from top to bottom of the stairs. Have some one hold the 1X so it don't move at all. Plumb the skirt at the top and at the bottom. Make a mark. If there is a 2X4 spacer, like there should be against the wall, be sure to clean any trash out so the 1X will lay all the way to the bottom of the spacer. Once in place check to see how much you will need to cut off the bottom of the bottom of the skirt and make a level mark and cut as described above.
Lay skirt board back onto the spacer if you didn't measure, and see how much you need to cut off the top cut and make a mark and make a level mark there, cut and there ya are. Now if there is a landing or you have an open side all bets are off. I hope this is clear but more than likely it isn't.