Here's a method I use to keep nails — and squeaks —
out of staircases I build on site (1). On a new-construction
job, like the one shown here, it's a good idea to give the
drywallers a heads up; they can cut the pieces that go on the
bottom of the stringers and set them aside for installation
after the stairs are finished.
I start by preparing the skirtboards, first fitting them in
place (2). When transferring the locations of the treads and
risers, I don't automatically copy the stringer's actual shape.
Because the tips of a dimension-lumber rough stringer will
naturally shrink, I make the marks on the skirt reflect the
stringer's original shape, being careful to make the
intersections of the treads and risers exactly 90 degrees. I
also take care not to mark too low, so the parts don't bind and
bow when I assemble them.
Next I use a Forstner bit and drill guide (www.rocklerpro.com)
to drill a flat-bottomed hole where the tread noses will land
(3), then rout the dadoes for treads and risers (4). I make the
holes and dadoes 1/4 to 5/16 inch deep, and about 1/16 inch
wider than the tread and riser stock so that everything fits
Using my basic router, I have to take two passes with a
1/2-inch straight bit to get the desired depth, and two more
passes to get the right width. On an enclosed stair, one of the
skirtboards has to be "gutted" — that is, the material
behind the dadoes has to be removed all the way to the bottom
edge. This allows that skirtboard to slide along the wall and
into the finish treads and risers that have already been
loosely installed into the dadoes on the other
With one of the skirtboards nailed to the wall (preferably the
longer one) and the other clamped into position, I take
measurements for the treads and risers. I cut them 1/8 inch
short, then dry-assemble the whole stair (5).
Next I use a Kreg jig to drill pocket holes in the rough
stringers — usually two holes at every tread and riser
location (6, 7). Having already done a dry fit, I'm ready to
use glue; PL urethane has a long working time and fills gaps of
up to 3/8 inch wide.
Armed with a bunch of shims and 1 1/4-inch screws, I work from
the top down, gluing and screwing the staircase together.
Anywhere I have a gap greater than 1/4 inch, I'll run in a 1
1/2-inch screw. The shims wedge the parts tight against the
front edge of the dadoes, and the urethane glue expands to fill
the voids (8). I also use 1 5/8-inch trim-head screws to secure
the backs of the treads to the bottoms of the risers. Once
everything is put together, I pack PL into any remaining
By the way, it's a good idea to drill pocket-screw holes in the
back of the bottom riser. This allows you to pocket-screw it to
the wood floor before it gets covered with the tread.Mark O'Neil runs Xylem Construction in