I'm trying to design a code-compliant (UBC 1997) U-shaped staircase
for a fairly tight space, so I thought I would look at winder
staircases. What I've found is that the 6-inch minimum tread width at
the short end basically means that for a 90 degree turn,
code-compliant winders don't really save any space over just using a
landing. Is this what other people have found, or am I missing
something? A table of my calculations is below.
BTW, how does one make stringers for a winder staircase?
Footprint for effecting a 90-degree turn
10" tread depth (measured 12" in on the winders)
6" minimum winder short edge
Offsets measured from inside corners of steps above and below turn
Steps With Landing Winders
1 (0,0) N/A
2 (10,0) (6,6)
3 (10,10) (10.25,10.25)
4 (20,10) (14.2,14.2)
5 (20,20) (18.1,18.1)
For 4 steps and below, the 6" short edge determines winder size
For 5 steps and above, the 10" tread depth determines winder size
You would be hard pressed to find a building codes official that likes
They were, in the past, a carpenter's solution to a tight space
The winders from my second to third floor are about two inches at the
short end and they are something to cause worry in a parent of young
and hurried children.
These were put in long before any such thing as building codes
You won't find off the shelf framing for winders, they are a
vernacular expression and must be done onsite by the carpenter.
Unfortunately, you will find little relief by going to circular
stairs, as they have restrictions on minimum depth and width which
make their code compliant use restricted to situations where the
available overall height makes sense in relation to the footprint -
not the usual case when one is considering winder stairs.
If you are in an older building, you may be able to sell the idea that
you are conforming to existing or previous usage - but the response to
this will vary with the jurisdiction and the individual official.
If the floor that you are trying to access can be considered (perhaps
only for the purpose of getting permitted) as storage space, rather
than living space, you might find that the regulations are relaxed, at
the local level.
"People funny. Life a funny thing." Sonny Liston
Thomas J.Watson - Cabinetmaker (ret.)
tjwatson1ATcomcastDOTnet (real email)
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