Traditionally, a straight run of stairs gets a skirt board
on both sides. The wall skirt runs on the same plane as the
flooring baseboard and gets finished out with the same base
cap. On the open side, the face skirt acts as an apron running
below the treads, and also gets finished out with base —
except here the cap is run upside down.
Wall skirt. I’ve seen old-timers scribe and notch the
wall skirt around each tread. I’ve tried it once or
twice, and it’s come out okay. But it’s tricky, and
if it doesn’t come out right the first time, you can end
up chasing an elusive good fit forever when you try to tune it
up. I don’t think it’s worth it. Instead, I always
leave a gap between my rough stair and the wall by installing a
2x4 between the bottom edge of my first rough stringer and the
wall studs. This leaves room for the drywall to be slipped down
first, followed by a 1x10 wall skirt.
To mark the cuts for the wall skirt, I temporarily tack the
uncut board along the corners of the rough treads (Figure
4: To notch the wall skirt around the landing
framing, the author tacks the wall skirt along the
nosings of the rough treads and marks a level line one
standard rise above the landing floor.
I then set a compass to the distance of one rise and scribe
level cuts at the main floor and the landing floor. This scribe
technique allows the cut wall skirt to slide down flush to the
floor so that its bottom edge will be hidden behind the finish
treads and risers. I use a level to mark a plumb cut line at
the top where the skirt hits the landing. This plumb cut line
intersects the landing level cut line and together they mark a
notch that fits around the landing where it’s attached to
the wall (the landing is not spaced away from the wall the way
the stringers are).
If you’re tying into baseboard that is thinner than
3/4 inch, I recommend you plumb-cut the wall skirt at the top
and bottom to simply catch the baseboard. But, if you’re
using two-piece or 3/4-inch baseboard, you’ll want your
baseboard to continue down the stairs as your wall skirt.
Decide on the height of the baseboard first, then set the skirt
board so the top edges will meet in a smooth transition.
Instead of making a plumb joint, which exposes end grain on the
skirt board, I prefer to make a miter cut. If you know the
theoretical angle, you can simply halve it. If not, you can use
a simple compass technique to manually bisect the angle ().
Face skirt. The face
skirt has level cuts at all tread overhangs and vertical miter
cuts that will tie into the risers (Figure 6).
6: To scribe the face skirt, the author uses a
level to mark true plumb and level cuts for each
sub-riser and sub-tread.
When installing the face skirt, I nail only along the bottom
edge, so the top is "flapping in the wind." That way, later on,
I can move the top of the board to align it with the miters on
the risers. Don’t forget to glue the ends of the face
skirt to the newel posts.
To cut the face skirt to length, first make a plumb cut
where the skirt meets the bottom newel. I usually cut this to
the theoretical plumb cut for the stair — 36.9 degrees in
this case. Then, I hold it in place and mark the top plumb cut
where it meets the landing newel. At this point, I can’t
assume that my newel posts are perfectly parallel, so I cut the
skirt slightly long, then scribe it to fit with a sharp block
After fitting the face skirt to length, I tack it over the
ends of the rough stair, holding it a little high to allow for
the top corners of the finish risers, which are going to be 3/4
inch proud of the rough riser. I then use a level to mark the
cuts for each rise and run. Because the framing may be slightly
out of square, I center the bubble for each line I mark. Then I
pull the board off, and using the same level, I transfer the
lines back where the cut needs to be made.
These lines are on the inside of the skirt board. The plumb
cuts, which will miter into the risers, will be cut on a
45-degree bevel, and the horizontal cuts will be square. I
start by cutting the miters. This is a right-hand stair (when
you look up the stair, the handrail is on the right-hand side),
so I can cut the miters with a circular saw, which usually has
the blade set to the right. On a left-hand stair, I would need
to use a saw with the blade set on the left side, like most
worm drives. Cutting from the backside of the face skirt, where
the marks are, you can overcut the miters a little in the
corners, because the kerf won’t show through on the face.
This makes it possible to remove the triangles entirely when
making the level cuts.