Installing Manufactured Stairs, continued
The stairs come from the shop with the finish floor height
and centerline marked on the lowest riser (Figure 9). If you
have to trim or shim that, do it so that the change is minor in
the center walking path. By code, you have 1/4 inch to play
with -- more than you'll probably ever need. Coming out of the
shop, I've never seen any of the rise or run dimensions on the
stairs themselves deviate from dead-on perfect.
9. The installer uses a piece of landing tread,
supplied with the stairs, to check the fit at the top
(left). A label on the lowest riser (right) shows the
finish floor height and indicates the centerline of the
At the top, lay a scrap of landing tread on the riser to
check the height. The landing tread comes with the stairs and
makes the transition from the 1 1/16-inch tread thickness to
the 3/4-inch wood flooring thickness; we install it when we
install the floor. The stairs are right when the scrap lies
flat on the subfloor and fits just right on the riser.
Fastening. The stairs are fastened to the wall
studs at the side, under the steps if possible (Figure 10). We
also pin them to the landing, and to a cleat screwed into the
subfloor behind the bottom riser. Drywall screws seem to work
fine for all these locations; when we have to place screws in
the stringer above the steps, we countersink them, then plug
and sand. Never use nails instead of screws -- that's the one
thing that is likely to cause squeaking over time.
Figure 10. A cleat
glued and screwed to the deck serves to hold the bottom
stringer tight to the floor (upper left). Screws into
the cleat through the face of the stringer will be
buried behind flooring and molding. Screws into the
studs from underneath are also invisible (upper right).
Visible fasteners (left) are counter sunk and
All around the staircase, we use 5/8-inch shims at the
fastening points to hold the assembly away from the framing
(Figure 11). That lets us slide drywall behind the stairs
later. The joint between wall and stairs will eventually end up
being covered with a cove or quarter-round molding.
Figure 11. A 5/8-inch
gap is left for installing drywall around the stairs
(left). Precut shims (right) speed this process.
Support. On the job we're showing, the shop's
installer put temporary bracing under each run of stairs at
mid-span (Figure 12). If it were one long run, he'd have put in
two braces. It's a good idea to shim the supports to create a
slight crown, say, 1/4 inch or so; as lumber shrinks,
everything tends to settle and sag a little.
Figure 12. Before
leaving, the stair installer places temporary braces at
mid-span in each run of stairs. It's best to build in a
crown of perhaps 1/4 inch to allow for slight settling
and framing lumber shrinkage over time.
If my crew were installing, we'd probably frame up the wall
right away, just like any other stud wall, with the top plate
right up under the stair treads and with a 5/8-inch gap between
the framing and the stringer to accommodate drywall. Again,
we'd shim slightly to create that crown.
Making the Choice
Depending on your situation, you may have good reasons for
wanting to build stairs yourself. If you're a builder who loves
being a craftsman, and if stairs are a big source of
satisfaction, you might not want to give that up.
But the reality of my business is that I have to provide the
best quality I can within a limited budget. As a small-volume
custom builder in a tight labor market, I have to use my
skilled workers as efficiently as possible. I can't afford to
keep a finish carpenter on staff just to build stairs.
Manufactured stairs give me and my customers the best value
available, and I see no reason to go back.
Andrew P. DiGiammois a design-builder living in Assonet,