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WILL1E
Moderator
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# Posted: 21 Dec 2021 09:18am
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Getting to the point i need to build the stairs to the loft and i have a couple unanswered questions since i've never built stairs aside from a couple steps going to a deck using precut stringers.
Stairs will be 36" wide and will get me from the main floor to the loft floor which is 106" up. Each treads will have a run of 9" and a rise of 8".
1. Are 3 stringers sufficient for 36" wide set of stairs?
2. Is 3/4" plywood sufficient for the tread surface (not sure what final floor covering will be yet, i suspect carpet) or do i need thicker?
3. Since i'll be cutting my own stringers, is there a magic number to keep in mind to ensure there is enough board left from the inside corner of tread/riser and the bottom edge of the stringer so it doesn't snap in the middle as i'm walking up?
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Nate R
Member
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# Posted: 21 Dec 2021 09:21am
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I've also only done deck stairs, so this is all with a big grain of salt. 
I believe 3 are fine, but 4 if go wider than 36.
I believe 3/4" ply is often used..... So I *think* so.
Looks like the magic number is 3 1/2"? https://weekendbuilds.com/stair-stringers-2x10-or-2x12/
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travellerw
Member
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# Posted: 21 Dec 2021 10:34am
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Stairs are tough.. Actually, building mine was some of the most challenging work I have done on the cabin. Its all in the planning and math (after that its just easy cutting). Ensuring the math is right so you get the correct angle at the top and bottom of the stairs is the hard part.Take your time and check everything like 5 times! Careful relying on online calculators, I found errors in at least 2 of them!
First, code differs quite a bit on stairs. Use google to see if you can find your local code. It will have all the rules about rise, run, deviance, overhang (required), stringers and thickness.
For mine, I did what some contractors refer to as a laminated stair. Basically the rise piece supports the run. You then use minimum 1" OSB (or ply) as the run (preferable 1.25"). This allows you to only use 2 stringers on a 36" wide stair. Everything is glued nailed. In modern construction the stringers are actually routed and the run and rise pieces are slotted in and held with wedges, glue and nails. This is the strongest as you aren't cutting out giant chunks of the 2by. However, that is near impossible for us mortals so a traditional stringer is best. You MUST ensure that the stringer is never less that 5" at any of your cuts. A 2X12 should be adequate!
Not sure what you decided on for a design. In our install, there is a 2x4 wall on either side so the stringers are nailed to that for additional support (they are super sturdy now).
The code up here is minimum 1" material for the run no matter what type of stairs you build or the number of stringers.
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Brettny
Member
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# Posted: 21 Dec 2021 11:01am
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This calculator helped me quite a bit build my last set of stairs.
https://www.calculator.net/stair-calculator.html?run=10&rununit=inch&totalrun=15&tota lrununit=foot&ctype=one&totalheight=106&totalheightunit=inch&x=55&y=32
If I remember right your did a gambrel roof. I'm doing the same and I found that putting the stairs up the exterior wall with a landing then up to the center of the building kept the most heat room in the loft. Like so..
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WILL1E
Moderator
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# Posted: 21 Dec 2021 01:45pm
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I've read through the local code several times and it doesn't say anything about number of stringers, materials or anything like that related to the stairs...hence why i was asking.
@Brettny, only way i could run along a way at this point would be to remove a window which ain't happening!
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Atlincabin
Member
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# Posted: 21 Dec 2021 02:13pm
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I built some 36" wide deck stairs using 2x12 stringers on the ends of the steps and 2x12 steps. I used the table saw to cut grooves about halfway through the thickness of the stringers and then set the steps into the grooves, put three deck screws into each end of every step (through the stringers). No risers, as it's a deck stair, but you could easily put risers in. No noticeable deflection of the steps as is.
Just another way to do it FYI.
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travellerw
Member
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# Posted: 21 Dec 2021 03:02pm
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Quoting: WILL1E I've read through the local code several times and it doesn't say anything about number of stringers, materials or anything like that related to the stairs...hence why i was asking.
Wow.. Very strange they don't call it out. If that is the case, then the first thing I would do is try to have a quick phone call with an inspector. The buck stops with them, so this is really the only way to get a %100 answer. I wouldn't trust going off an answer you get here. It would be disastrous to have to rip out the stairs because the inspector didn't accept it!
Inspectors are human and the good ones look at things as a whole. (e.g. If you have a stairway with 2X4 walls either side that the stringers are tied into, then really your stringer span is only as long as a single 9" run and the stringers are carrying little load.)
However.. Usually if its not specifically called out in code, then it defaults to IBC. I don't have an IBC book and can't seem to find anything online.
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Nate R
Member
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# Posted: 21 Dec 2021 03:32pm
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I looked, and only found this:
https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environ ment/320_325/325_b.pdf
This is for DECKS. But seems the state freaked out about deck code in 2003 and added a bunch of stuff to that....Interesting, I can't find ANY other mention of stringers for residential stuff. For commercial buildings, they DO call out specifics for fire code stairs, etc. Odd.
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snobdds
Member
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# Posted: 21 Dec 2021 06:35pm
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I love making stairs...it's therapeutic.
For my cabin, I wanted to use the gable end walls to my advantage and to minimize the amount of loft space lost. I started the stairs on the eve wall, then transitioned up the gable wall the last 4 steps. I built a landing in the corner and put steps down and up from there.
I used Doug fir 2x12 and only used two. Then I used 2x cedar for the treads. I made it ergonomical for my dad to get up and down. It really takes up minimal space.
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WILL1E
Moderator
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# Posted: 22 Dec 2021 08:04am
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Yeah, this whole stairs thing has been a weird one. When i designed my place (photo below), i missed the part of the code where i had to maintain a 6'4" clearance for 36" at the top of the stairs. I thought it was only vertical from the nose of the last step. So plan B was to put the stairs perpendicular to the wall next to the bathroom door. But following code, this causes the stairs to jet out quite a ways into the living area.
So i've been emailing back and forth with the BI to see what options i had as a spiral stairs wasn't really going to save me any square footage. I asked if i could use the max riser height of a spiral stair case which was 9.5" vs. 8" for straight stairs. I also asked if i could use the minimum width of a spiral staircase but for a straight one which would allow me to have a 5" narrower set of stairs. She emailed the state and they said no and not to waste there time with asking/applying for a variance. She said the state is very stringent on staircases because of all the lawsuits around them.
But here is the best part, they said that if I can't comply to the staircase guidelines that i should build a ladder and follow those guidelines as that's my only other option......WHAT?!?!?! Your worried about lawsuits and you'd rather me build a steep ladder vs. a straight set of stairs that follow spiral staircase specs vs. the straight ones?!
So her answer to my problem is to follow the code for stairs, or build a ladder, and as she said, she can't control what i do with that ladder after final inspection 
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Brettny
Member
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# Posted: 22 Dec 2021 08:43am
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Ladder inspection then stairs sounds like what I would do.
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jsahara24
Member
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# Posted: 22 Dec 2021 09:11am
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Yup, ladder inspection then do what you need to....Gotta love regulations...
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mj1angier
Member
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# Posted: 23 Dec 2021 07:41am
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At least she gave you a way around the "code" lol
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Saabu
Member
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# Posted: 4 Jan 2022 01:27pm
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hey Will i know you were having trouble getting a 'code' staircase to fit in your cabin. So check out this youtube link and the staircase they built. i know the guy who designed the cabin so could prolly get you the specs.
https://m.youtube.com/watch?v=P-z3lj-xB8c
or search Margaree Valley NS (nova scotia) and you'll find it. it was a video that a young couple shot while they were staying at the cabin.
Wayne in Calgary
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BRADISH
Member
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# Posted: 5 Jan 2022 02:03am
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This entire thread makes me so glad there is no BI inspection in our neck of the woods! What a headache to work with!
Best of luck. Looking forward to seeing your finished "ladder."
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WILL1E
Moderator
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# Posted: 5 Jan 2022 07:48am
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Yeah, your lucky! However, although she hasn't been onsite yet, i'm happy to have the BI I have for my area. I've heard nothing but good things about how she operates, hence the reason i bought in this county and why i'm trying to get this place built before she retires
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Saabu
Member
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# Posted: 10 Jan 2022 11:32pm
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Will did you see my post above?
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WILL1E
Moderator
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# Posted: 11 Jan 2022 08:09am
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Yeah, i've seen those elsewhere before. They're called ship stairs. Unfortunately, those are not code compliant for ladders.
My plan is to just build the area out where i intend to have stairs such that there will be stairs there eventually. But for now i'll build a code compliant ladder and then after final inspection i'll yank the ladder and build the stairs i want.
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Brettny
Member
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# Posted: 11 Jan 2022 10:17am
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I built a set of "ship" stairs for my shed. The rise is about 9ft and run roughly 30in. It's just steep enough to almost not needs to hold on. It's just slightly better than a ladder.
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gcrank1
Member
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# Posted: 11 Jan 2022 11:46am
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For over 30yrs we used a ladder to the loft. At first it was one with round rungs, worked but Not good! Then one with flat steps (think the front part of a step-ladder), waayyy better. I can recommend that as a minimum.
I never got around to building the ships-ladder I wanted. Fwiw, I would have made it with the bottom standing about 30% farther out (ie, less vertical) than a step-ladder for the ease of up/down and step treads about 2x as deep.
I should have done it while still 'enthusiastic'.
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