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I have gas!
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Discussion Starter #1 (Edited)
I'm building a short section of staircase (5 treads x 6 risers @ 8.25"R x9"T x 36" wide). It's borderline for me if I should use 3 or 4 stringers. 3 stringers would give me 16 1/4" OC. I'm building these out of 2x12 std lumber.
Are 3 strings enough for such a short staircase? The real reason I'm asking is because I screwed up one of the stringers.
TIA
 

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I have gas!
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Discussion Starter #2
If you're talking about the screwed up stringer... I cut on the wrong side of the :censored: line.
 

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Drywall contractor
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I'd say 3 stringers are fine. I always reinforce with a 2"x4"running the length of the stringer where the cuts for the tread and rise meet. One on the inside of the outer stringers and one on each side of the center stringer....
 

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Licensed P.E./Home Insp
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How did you get a permit, with 3 stringers or 4? If you specified 4, and built 3, the inspector might bring that up.
 

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Our city just went with IRC, we used to be UBC.

You may want to check with your local B.D. for code as the IRC (2003) says 7-3/4" max. riser height and UBC 8" max. riser.

Minimum tread depth - IRC.... 10" UBC .... 9"

The weak points in your stringers are at the V point of the landing notch. The downward pressure (load) is concentrated on the middle area of the level cut on the landing. Picture the tread/riser broken off with the wood grain, and the notched area splitting at the v notch. You'll be left with a 4" piece (rip) of material carrying the center treads. Your set is small, I wouldn't worry. If you had a longer set, I always level cut the waste piece overhanging the landing (air wood) the thickness of a 2x6, or two. Add them to give total support.

Actually, I plan for full bearing of all stringers on the landing return. Your landing would extend another 6" into the closet space. And I always add 2x4's as stated, for a finish stair skirt board, next to drywall. If wallboard only, I add 3/4" material instead. (for wallboard, don't have to stair-step the cuts) Some would make you fix or replace this if not to code, when you go to sell the place. Be safe, G
 

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Licensed P.E./Home Insp
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Now I see the picture. Didn't see it before for whatever reason.

It's good practice to use nailers at the bottom of the stringers, and to have full support under the stringer. Yours are notched, with a little bit dangling down there. I allow that with engineered material sometimes depending on the amount of meat, but not with regular dimensional lumber. It's weak at that connection. So normal practice is to design the landing so the bottom of the stringer sits on it (with a nailer). In this case I would put knock the danglers off and install some supporting headers to the face of the rim joist to carry the stringer loads.
 

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Old School
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The majority of stairs are made with just two stringers. Three is reasonably common enough, but I have never built regular stairs with four or more stringers unless the stairs were to go all the way across a wide expance of porch front, or something like that.

If you did screw up the cuts on one stringer, make sure the lowest stringer is the one in the middle, or you will have a "rocking" situation. Snug up glued shims to take up the slack on that center one.

And I wouldn't give a second thought about going with four stringers. Although done in metal, I have installed several sets of mono-stringer (one stringer) stairs over the years. Never a problem.

By the way, did you get official building dept. "sign-off" on your riser and tread measurements? They wouldn't fly here.
 

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Drywall contractor
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Oops. Didn't catch the riser/tread measurements. Not code here either...
 

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I have gas!
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Discussion Starter #11 (Edited)
Words from my father came back to haunt me. If I just put the time into correcting it and not so much time trying to figure a way to get around it, I'd be done by now. I think 3 stringers would have been fine but I sucked it up and bought another piece lumber and just finished cutting it... Done...

Code in Massachusetts is 8 1/4 x 9, this is mostly what the inspector was concerned with but after looking at the drawing again, it did show 4 stringers. The stairs I tore out ranged from 8 3/8 - 8 9/16 Rise by slightly short of 9 Tread with turners in the middle. I must have fallen down those stairs a dozen times.
 

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I have gas!
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Discussion Starter #12 (Edited)
The weak points in your stringers are at the V point of the landing notch. The downward pressure (load) is concentrated on the middle area of the level cut on the landing. Picture the tread/riser broken off with the wood grain, and the notched area splitting at the v notch. You'll be left with a 4" piece (rip) of material carrying the center treads. Your set is small, I wouldn't worry. If you had a longer set, I always level cut the waste piece overhanging the landing (air wood) the thickness of a 2x6, or two. Add them to give total support.

Actually, I plan for full bearing of all stringers on the landing return. Your landing would extend another 6" into the closet space. And I always add 2x4's as stated, for a finish stair skirt board, next to drywall. If wallboard only, I add 3/4" material instead. (for wallboard, don't have to stair-step the cuts) Some would make you fix or replace this if not to code, when you go to sell the place. Be safe, G
That was thought of and I was nervous about the notch as well, but there will be another staircase directly below this leading to the basement and headspace was an issue.

Thanks Aggie, that's a good idea. I can ledger bolt a couple of 2x6s to the landing.
 

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Old School
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to get more space why don't you use this stair? it's more beautiful and useful
Pretty, but I've lived with spiral staircases before. Unless very large and of the sweeping variety, they are a major PITA! I wouldn't wish them on my worst enemy. :)
 

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Old School
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sorry to give you an useless information.
Not useless at all. Obviously, lots of people like them. My only suggestion is to use a set for awhile before investing in them. Heck, ya might love them. Just because I don't like them, means nothing. I don't like caviar either... just low-class here. :wink:

Sorry if I came on too strong... didn't mean to.
 

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I have gas!
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Discussion Starter #17
I like spiral staircases but one of the reasons we decided to relocate the staircase is because we couldn't get the box spring up the stairs. I couldn't imagine the difficulty in trying to negotiate furniture up a spiral.
 
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