Building Stairs
To frame a deck stairway, you need to figure out the number of treads (steps)
required and the rise and run (depth) of each tread.
First,
measure the height of the deck.
Then
divide the height by 7 (a typical stairway rise). If the answer's a whole number,
then that's the number of treads you'll need.
If
the answer ends in a fraction, then round it off to the nearest whole number. That'll
be the number of treads. Divide that into the height. That gives you the rise
you'll need for that number of treads.
To
determine the most comfortable run of your treads (the length), divide the rise
into 75. So with a typical rise of 7 inches, a typical run might be 101/2 inches.
A rise of 71/2 inches would work best with a run of 10 inches. But this socalled
"comfort formula" does allow some leeway, so layouts of 612 (72) and 711 (77)
work out fine.
TIP: On deck stairs, a run of 10 inches always works great because you can use 3
2x4's (for a total width of 101/2 inches wide) or 2 2x6's (11 inches wide) for
the treads, leaving a nice 1/2inch or 1inch overhang at the front of the tread.
Laying
out Stringers
You can lay out a stair stringer very quickly with a framing square by finding
the rise on one leg and the run on the other leg and then lining those up with
the edge of the board.
Mark
along the edges of the square to create the first step. Then move down the board,
line up the square and draw the next step. Continue that until you've drawn all
the treads.
Cutting
Stringers
Use a circular saw to start all the cuts.
But
use a handsaw to finish them, since the circular saw blade leaves a little bit
uncut at each corner.
Tracing
Stringers
TIP: All stairways require at least 2 stringers, and taller or wider ones require 3. (Always check with your local building department.) But
rather than lay each one out individually with the framing square, cut the first
stringer out and use that one as a pattern for the others.
Bracing
Stringers
You can install each stringer separately, but it's usually quicker to connect
them together with braces before setting them in place.
Notch
out each stringer for 2x4 braces at the top, middle and bottom.Screw
the braces in to each stringer.
Attaching
Stringers
Set the stringers in place against the rim joist and nail through the top brace
into the rim to hold it.
Lag
screw through the brace into the rim joists to secure them permanently, predrilling
for each screw.
Installing
Treads
Cut the treads to fit over the stringers, leaving a 3quarter inch overhang on
each side to serve as a drip edge and keep rain from dripping down onto the stringers.
Screw or nail the treads down into the stringers to finish the stairs.
