Risers and Treads
At this point, the newel posts are up and the skirt boards
are cut and installed. The bottom step has a radius-end tread,
which installs on a premanufactured wraparound riser box that
returns to the bottom newel post. On the second and top steps,
the risers and treads must be scribed to the newel posts. The
landing requires a special tread with a rabbeted underside so
that its top is at the same level as the 3/4-inch strip
flooring, but from the front it will appear to be as thick as a
manufactured tread (1-1/16-inch).
Installing risers. Eventually, the
risers will sit on and cover the treads. With the type of frame
that I build, the treads are well supported and won’t
move up and down — so this gap along the riser edge is
going to stay tight. But the treads are usually around a foot
wide and they’re going to move as the humidity varies. I
run the tread under the riser edge so that any movement does
not show up as a gap.
Risers can be ripped to a width equal to the net rise minus
the tread thickness. For measuring and marking risers and other
pieces that meet the wall skirt on one end and the newel post
on the other end, I use my handmade stair gauge (Figure 7).
| Figure
8: The author spaces the finish risers off the
sub-treads before gluing the miter joint and nailing
the riser off (top). He then notches the face skirt to
make way for the treads later on (bottom). The depth of
the notches equals the tread width minus the net run
minus the overhang. For example, if the treads are
11-1/2 inches, and the net run is 10 inches, and
there’s a 1-1/8 overhang, the face skirt needs to
be notched 3/8 inch. |
|
Treads.
Manufactured
treads are reversible because they are sanded on both sides.
After scribing each tread to fit (Figure 9), I put construction
adhesive on the underside of each of the treads and slide them
underneath the already installed risers.
Figure
9: To install treads, the author first cuts them
approximately to length — to within scribing range. He
then puts them each in place temporarily, making sure the
overhang along the front is even. After setting a scribe to the
distance between the nosing return and the face skirt, he marks
that dimension against the wall skirt. On steps with newel
posts, he also has to scribe around the newel post.
If the fit is tight, try using a 5-lb. non-marring rubber
hammer to persuade them into place. I use my white rubber
Porta-Nailer mallet. Be sure to double-check the overhang.
The risers will pin the treads to the frame on the backside,
but the treads still have to be nailed off along the front to
ensure a good glue bond. To finish out the treads, I glue, and
brad scotia molding under the tread nosing and nosing
return.
Handrail and Balusters
I
cut the handrail the same way I cut the face skirt. First I cut
the bottom to the theoretical angle, then I prop the rail into
place and mark the other end. I cut it a little long on the
first try so I can trim it until I have a good fit. While
checking the fit, I’m careful not to push the newels out
of plumb. I temporarily fasten the handrail with 3-1/2-inch
countersunk screws through the newel posts. Later, I fill the
holes on the newel posts with bungs taken from scraps of the
same wood. However, before permanently installing the handrail,
you need to lay out the balusters.
Baluster spacing.
Most
codes require a maximum 4-inch space between balusters ().
Remember that if you’re using balusters that have been
turned on a lathe, the maximum spacing rule applies to the
thinnest portion along the profile. If you have a turned
baluster with a 1-1/4-inch base on a 10-inch tread, you
actually end up needing three balusters per tread. With
1-3/4-inch balusters on 9-1/2-inch treads, you might only need
two per tread.
The corner of the first baluster goes right over the corner
of the riser and the face skirt. With 1-1/4-inch balusters and
a 1-1/8-inch overhang, the centerline is 1-3/4 inches in from
the edge. After measuring in from both the side and the front,
mark the centerpoint of the first baluster on each tread. To
measure the other two baluster centerpoints on a tread,
calculate the spacing based on the net run — so that the
spacing between the last baluster on one tread and the first of
the next is the same as the spacing between the balusters on
the same tread. With a 10-inch run and three balusters per
tread, you can divide 10 by 3 using the 12th scale on your
framing square.
Once you have centerpoints marked on the treads, you can
transfer them up to the handrail with a level or plumb bob. At
this point, the balusters need to be cut to length and holes
drilled in the underside of the handrail, taking care not to
blast through the top. I find drilling baluster holes while the
rail is temporarily fastened in place works well.
With balusters, I like to see the detail of the turnings
follow the pitch of the rail down the stairs. I do this by
varying the height of the bottom baluster blocks. In addition,
I think that manufactured stock balusters often have
ridiculously long bottom squares. I like the longest bottom
square on a baluster to be just one rise in height.
On a staircase with a net rise of 7-1/2 inches, the three
balusters on each tread will become successively shorter by 1/3
of the rise, or 2-1/2 inches. That makes the bottom squares
7-1/2, 5, and 2-1/2 inches, back to front. After the bottom
squares are cut, pin-top balusters should be cut so that they
extend at least 3/4 inch into the rail. Square-top balusters
should be individually fit and cut so that they butt into the
underside of the rail.
For attaching balusters to the treads, all of the stair
manufacturers provide a type of dowel screw (a screw that has a
lag-type thread on both ends). When screwed into the bottom of
a tread, 1/4 x 2-1/4-inch dowel screws really hold a baluster
down. To use dowel screws, you have to predrill holes in both
the treads and balusters. Some manufacturers predrill the
balusters.
To install the balusters, remove the handrail and use the
dowel screws to attach the bottoms, making sure the squares
line up. Using dowel screws with square-top balusters is harder
because they need to tighten to one exact orientation. But with
some fiddling, it’s still the best possible option.
Setting the handrail.
For pin-top balusters, place glue on the baluster tops and
handrail ends. Set the handrail onto the balusters and
permanently fasten it into position. Use 1-1/4-inch brads to
hold the balusters in position. For square-top balusters,
fasten the handrail into position and then plumb, glue, and
nail each baluster to the underside of the rail, taking care to
center the baluster on the rail.
When post-to-post newels are turned on the lathe, blocks are
left at the bottom for attaching the newel to the carriage and
at the top where the handrails attach. Rails are typically
attached to newel posts one inch below the edge of the top
blocks.
Newel lengths.
To
determine the length of a , you have to carry the line of the
top of the handrail across to the front side of the newel to a
point exactly over the nose of the second tread (slightly in
from the newel edge, to allow the nosing to die into the newel
with a slight reveal). This requires knowing the angle or pitch
of the staircase. Although you can estimate the angle with a
sliding T-bevel, I like to use a calculator for added
precision. The angle equals the inverse tangent of the
rise/run. On a scientific calculator enter Rise ÷ Run =
Inv Tan. Or with a Construction Master calculator, enter the
rise per tread and the run per tread and push Pitch. With a
rise of 7.5 and a run of 10, it’s 36.9 degrees.
From this point, measure down 32 inches to where the level
of the finish tread nose will be. Because the finish tread
slides under the bottom newel, this line becomes the top of the
pocket notch. To create as strong a connection as possible, I
extend the bottom newel all the way down to the subfloor so
that the flooring sub can lock the post in place with his
flooring. If I don’t beat the flooring sub to the job,
I’ve got to give up on this detail and scribe it to the
finish floor.
The is a little bit different — it has a longer top
block that allows it to pick up both the landing rail at a
height of 36 inches and the rake rail at 32. Leaving a 1-inch
reveal above the landing rail, the top edge of the newel block
has to be 37 inches over the finish floor. The bottom end of
the landing newel should extend below the face skirt board.
Typically, you also have an apron on the landing. If the stair
turns and rises up the next run, the next face skirt will also
butt into the landing newel. In either case, it’s common
to run base cap upside-down on the apron, or under the face
skirts, and your newel has to be long enough to catch
everything. I always draw it out full-size (either on the wall
or on paper) to determine what that length is. Typically
it’s around 17 inches if you use a 1x10 for your skirt
board.
Pocket notches.
Newel
pocket notches need to position a newel front to back so that
the tread or landing overhang dies into the newel, and side to
side so that the newel is centered on the handrail/balustrade
centerline. Front to back, we know that there’s a
1-1/8-inch overhang plus a 3/4-inch riser plus a 1/8-inch
reveal. That’s 2 inches, which brings us to where the
bottom portion of the cut is made. Side-to-side in our example
(with 1-1/4-inch balusters, 5/8-inch drywall, 1 x 10-inch skirt
board, 1/8-inch reveal), the side of the notch cut ends up
being 1/8-inch beyond the center of the newel.
Beyond this, layout differs for bottom and top newels. For
the bottom newel, the lower section must be cut to fit around
the curved riser box used for the first step. In addition, the
pocket needs to make way for the tread to slide underneath. And
over the tread, the notch positions the newel front to back so
that it catches the overhang of the next tread up. For a
landing newel, the pocket positions the newel from front to
back in the same manner. On the lower portion of the cut,
however, the newel runs full width.
Jed Dixon operates North Road Stairbuilders in Foster,
R.I., and has made several presentations at JLC’s
Construction Business and Technology Conferences.