Spiral Stairs * Installation Planning
I am in the planning stage for an 11′ height (10′ for the room height + 1′ joist thickness) wooden spiral stair. At the top, I need to build a landing. My question is: As I enter the stairs at 6 o’clock direction, I would like to exit the stairs at 9 o’clock at the top. Is this something that is flexible, or is there a strict rule on where you must exit based on stairs height? Advertisers don’t offer any of these guiding details. I can really use some practical advice from guys who have done this.
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There is the strict rule that you should have the specs of the stair on hand before you frame the opening for such a stair, if you want to buy an off the shelf sort of stair. If it's custom, talk to the person who's making it- there are a lot of variables in curved/spiral stairs.
Of course, the stair needs the clearance above each tread, so there is a minimum height of a full spiral- 7' or so. Best of luck,
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
Edited 3/28/2007 12:32 am by zak
>Advertisers don't offer any of these guiding details.
Some do.
http://www.stairwaysinc.com/resources_design_information.htm
http://www.stairways.org/pdf/2003%20Stair%20IRC%20SCREEN.pdf
Latest specs I've been using...30 degree treads with max 9.5" riser. For 11' floor-to-floor, that'll mean 13 treads, so 6:00 start means 7:00 end if clockwise down. To make the end 9:00 would be to increase the tread angle--I've not seen treads > 30 degrees, and make sure you wouldn't violate the 6'6" min headroom requirement.
I put my spiral in yesterday, 62" was the quoted rough opening.One baluster almost rubs the wall, and the hand rail just misses the floor joist in one spot.64" would have been min, and 68 would not have hurt.So even if you know the specs, it still doesn't always work out .A medium to large guy named Alan, not an ambiguous female....NOT that there is anything wrong with that.
Let's see if I have my math correct. I want to enter bottom at 3 oclock, and exit top at 12 o'clock, so that's 450 degrees. Each step being 30 degrees, means I have 15 steps. I have 132" of rise (11' height), divided by 15 steps give me 8.8" each riser. Is this adequate for me to start planning my landing above for any generic spiral stairs, or need I do more math or research? Thx.
15 treads would be 16 risers, so you'd have to divide by that, and not the 15. That's 8.25". Then what you'd have to calc is if that left you enough headroom where the treads overlapped and beneath the landing. There's a reason spirals usually have taller risers (over 9") and that's usually because of headroom. Remember that you're measuring vertically from a diagonal line connecting the nose of each tread and another connecting the underneath of the stairs. The chart I linked you to shows that you need 13 treads and a 390 degree sweep according to their standards, and they're a pretty sharp company. I doubt you're going to be able to sweep it another 60 degrees and two treads without running into a problem somewhere.As for planning for any generic spiral, I don't think so. The construction of the stairs matters. A metal one is build differently from an all wood one. The treads are attached differently and supported differently. They have different attachments to the house framing. I think that once you know the floor-to-floor, you have to have a specific spiral design and spec, and then build the landing to that. For example, will the landing be sloped underneath to provide clearance, or will it be provided by the stair mfg? It needs to be part of the calc.
Are you saying that you want a 270° rotation as you ascend?
I cannot imagine why you can't get info from manufacturers. Have actually tried calling them or linking to tech support? In the past few years for manufactured items, I have yet to find one that does not make specs available, generally in CAD format onluine or in PDF format.
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Here you go for starters
http://www.arcways.com/spiralstairs.asp
http://www.arcat.com/divs/sec/sec05715.shtml
arcway has a CD with planning software that spits out a list of their components as I understand it.
See the other list too.
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Check this guy out: http://www.jself.com/stair/Stair.htm
His $20 set of plans walk you easily through the design AND construction of a set of spiral stairs, and there are gobs of pictures of spiral stairs people have built from his plans and sent in. Worth the $20 just to read in detail how it's done. Mark
I have 11' of rise (10' ceiling plus 1' joist) and I want to make 450 degrees of turn to exit at above. If I give the overall parameters of the project, you think a company could design from there? I'll try the companies shared with me. Thx.
I'd think that the available width of the space or radius would be important too.
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