STEP
BASICS:
Stairs should be used to connect the deck with the ground, especially
if the deck is more than 12 inches above the ground level. Stairs
can be 4, 5, and 6 ft. wide. If you plan to install a stair in the
deck design, it is best to postpone the installation of the decking
in the area of the stair until the stair has been installed. This
will allow you to build from above rather than from underneath.
However, if the deck is finished and you are adding a stair, the
construction techniques are not all that much different or difficult
to do. This
article will present a method of construction for a laminated stair.
Components-
The sides of the stairs are called "stringers" or "carriages" and
must be strong enough to support the heavy loads imposed by people
walking on the treads. Each step consists of a tread, which is the
horizontal piece, and the riser, which is the height between treads.
For
decks use a rise of 6 to 7 inches and a tread of 10 to 12 inches
To determine the number of risers, measure the distance from the
finished deck surface to the ground. If the ground falls away, measure
to the lowest spot possible.
Divide
the distance in inches by 6 or 7 inches of rise. If you get a whole
number, then that is the number of risers you need. In the event
the number is not even, round it off to the nearest whole number.
Then divide the original distance by that number to find the height
of each riser. Try to keep this height about 6 to 7 inches For example,
if the deck-to-ground measurement were 48 inches, you would require
eight risers of 6 inches each or seven risers of 6 inches To determine
the total run of the treads, multiply the tread width times the
number required. In the example above, since eight risers were required,
you would need eight treads of 10 inches each, for a total of 80
inches (6 feet, 8 inches) measuring from the face of the skirt down
to the ground.
The
stringers for the stair should be very strong. Use 2x10s or 2x12s
for short runs--less than 6 feet. If longer than 6 ft., use 2x12s
and reinforce the notched stringer with an additional unnotched
2x12.
Once
the tread and rise has been determined, start marking the pattern
onto the stringer. You will need a pencil and carpenter's square.
Mark the tread horizontally on the stringer and then the riser,
vertically. Repeat the procedure so the end of the square for each
rise coincides with the adjacent end of the tread you have just
marked. For each tread and riser, reposition the carpenter's square
and continue marking until you have completed the number required.
Make
sure that you leave at least four additional inches remaining on
the end of the stringer for attaching it to the footing or ground.
Following the lines you have marked onto the stringer, cut the marked
pieces. Your cuts must be square and true, otherwise you could have
an irregular tread. If you need to double up because the run is
over 6 foot., attach another stringer that has not been cut to the
outside of the one already cut. This will give you an extension
to which you can nail the next notched stringer, and provide the
additional stiffness.
The
Connection-
Connect the stringers to the skirt. The best way is to use metal
hangers or framing straps. This will guarantee that the stringers
will be stable and tight to the skirt.
Before
attaching the stringer, you may want to position a concrete footing
under the stringers to prevent shifting. Angle irons and bolts can
be used at the ground connection.
To
find the location of the first tread, measure down the height of
the riser, after subtracting 11/2 inches for the 2x4 decking, e.g.,
if the riser is 6 inches, mark off 4 1/2 inches Then move down 2
9/16 inches, the dimension of a 2x3 on edge, which will be laid
across the stringers to form the tread. If the tread is over 3 feet
wide, 2x4s laid on edge must be used. This then would require that
the top of the stringer be 3 1/2 inches below the top of the decking.
If
you are not using a laminate stair, adjust this dimension so that
it equals the height of the tread. The top of the stringer can be
trimmed to allow for this adjustment. Making sure that the 2x3s
(2x4s) are cut to length accurately, insert them one against the
other, nailing as you go. Use hot dipped galvanized nails. When
you get to the end of each tread, finish it with a uniform pattern
of nails. The end piece, called "nosing," is highly visible. One
variation is to put a 1/8 to 1/4 inch spacer between the studs laid
on edge. This will create a pattern similar to that of the decking.
Once all the treads have been installed, nail the sides of the studs
through the stringer.
Ground
Exit-
If the last step down exits to the ground rather than to another
deck surface, nail on the lowest cleats 2 inches from the top edge
of the stringers, flush with the cut on the end of the stringers,
and square from this cut.
Beneath
each cleat tack a piece of 4x4 on end (like a short post), flush
with the cut on the stringers. Tack the spacer to the cleats. Square
the stringer at the deck skirt, level the spacer, and plumb the
stringer cut. Finally, set the 4x4s in concrete you mix, or use
pier blocks.
Other
Options-
Many home center stores and building material outlets stock precut
stair stringers. Usually, the stringers are "short run," but if
your deck measurements qualify, these stringers could be a perfect
ft saving you the time and trouble of laying out the notches and
cutting them perfectly square.
Another
option, if you don't trust your measuring and cutting ability, is
to have a millwork company make the stringers for you. Take the
measurements, as detailed above, to the millwork shop. Once cut,
you simply fasten the stringers in place and nail on the treads.
Still
another option is metal steps that you can buy commercially, or
have them fabricated by a metal-working shop. Or, you could form
the steps and place concrete in the forms. Neither the metal nor
the concrete may have the design factors that you are seeking, however.
Take the deck design into consideration before making this optional
decision.
