Winder stairs design

Hello,

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?

Thanks, Wayne

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 winder stairs.

They were, in the past, a carpenter's solution to a tight space problem.

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 existed.

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.

Regards, Tom.

"People funny. Life a funny thing." Sonny Liston

Thomas J.Watson - Cabinetmaker (ret.) tjwatson1ATcomcastDOTnet (real email)

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