I need to build a rough half-staircase to exit from my basement to
grade. It will be in a corner of the basement, so one side will be up
against a concrete retaining wall. I understand how to build the
stringers and that anything with a face in contact with the concrete
should be rot resistant. But I'm wondering how to make the various
Side wall stringer: directly to the concrete retaining wall? 3 3/4"
tapcons OK? How many?
At the top of the stringers: a ledger board on the concrete wall?
Joist hangers to attach each stringer to the ledge board?
Bottom of the stringers: directly to the concrete slab, or to a
furring strip on the floor? If directly, does this mean each stringer
needs to be rot resistant? How does one fasten the stringer here, in
either case? Toenailing into the furring strip?
P.S. I imagine wanting to finish the stairway in the future if I every
finish the basement. Anything I need to plan now?
The stair does not need to bolted to the side wall. Stairs are
self-supporting, and are structurally equivalent to an inclined beam.
As long as you have adequate connections at top and bottom, it's not
A ledger board at top is pretty standard. Joist hangers to the ledger
board is another possibility but affect the finished look. Another way
is to bolt 3/4" plywood to the vetical faces of the stringers and use
that to hang the top of the stair.
The bottom of the stair stringers are usually notched to fit around a
perpendicular 2x4 cleat bolted to the concrete floor.
Here's a link that may be helpful:
It shows LVL stringers, but is applicable in your situation.
You are correct that you want to keep the end of the stringers from
sitting on the concrete floor. They will tend to wick up any moisture
in the slab. If your basement is dry, and you don't anticipate any
problems, you can epoxy coat the cut ends of the stringers where they
touch the concrete. That's simple and a 95% solution at least.
I'd build the thing pretty much as a stand-alone self-supporting unit (think
mobile home steps), and maybe anchor to the wall with a couple of lag bolts
set in anchors. Hell, even a stack of appropriately sized 2x8 and 1/2"
plywood boxes, construction adhesived and toenailed together, would work.
Yes, any wood touching slab needs to be rot-resistant, and if these steps
face an outside weather door, you probably want the whole thing to be
treated wood. Deck department at big box may have a precut stair kit, if
your door is at a common deck height above interior slab. At the price of
good wood these days, especially if this thing is 'temporary', I'd also
check with the local mobile home and fire escape dealers and precast
concrete stores, and see if they have a scratch'n'dent or used prebuilt item
that would fit your needs, assuming you have a way to get it into the
basement. Don't forget that if there is a door at the top, especially one
that opens in, you want a landing. Inspectors frown on doors that open into
space, these days- dunno why.
OK, I like the idea of a ledger board. What's the best way to attach
the stringers to it, joist hangers, angle brackets, or toe nail? And
to attach the ledger board to the wall? This link says wedge anchors:
This obviously puts the bottom of the stringer against the concrete.
What about using a sleeper with the bottom of the stringer resting on
top of it the full width? Then again joist hangers, angle brackets or
toe nails. Wedge anchors to hold down the sleeper?
You could do that, or you could set the stringers on a
waterproof membrane such as that used under sole plates.
The wedge anchors or expansion anchors are all good to hold
down your sleeper. If you screw the sleeper to the bottom of
the stringers, then set the stair stringers in place, there is
no need for angle or joist hangers. You want to set the stair
stringers first, then bolt down the sleeper.
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