Stair stringer layout


Old 08-02-15, 06:59 PM
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Stair stringer layout

Hi all,
Question on depth of treads and I want to make sure I wasn't missing something.

I am trying to keep things simple and do a 7-1/2" rise and 10" run, based on numerous stair calculators and our actual height. 2, 5/4x6 boards is supposed to yield 11", which leaves a 1" overhang. Sounds simple, right?

We are doing a cumaru deck (hardwood, almost like ipe). They recommend 1/4" spacing due to being kiln dried and it will definitely expand as opposed to contract. Seeing as I'l have 2 gaps there, it seems like that is more like 11-1/2", so my runs would have to be 10 1/2" each to accommodate. If I come in just under that (10-3/8"), that puts it close to the 5" minimum throat, but should be doable.

Am I missing something here? None of the calculators or articles mention the board gap. Most simply imply that a 10" run is great for 2, 2x6's or what not for the treads.

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Old 08-02-15, 08:02 PM
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You have the right idea. Keep in mind that your sill nosing can be as small as 3/4" or as large as 1 1/4", but must not vary by more than 3/8" on the entire flight. (Section R311.7.4.3 IRC 2009)

So increasing your nosing to the maximum allowed (1 1/4") would accomodate one of your two 1/4" gaps without increasing the actual "run" cut into your stringer. So your run could be as small as 10 1/4". Making the run 1/4" longer will decrease the nosing by 1/4". (10 1/2" run = 1" nosing)

Hope you took into account that the last (bottom) riser on the stringer is shorter than the rest. Otherwise once you put the tread on it will be 1" taller than the rest.

I would recommend you paint all cut ends with Anchorseal 2. It will help prevent the ends from cracking/checking.
Old 08-03-15, 04:39 PM
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Thanks. I did take that into account. I started digging for the footings with the spacing farther out. I think it will be okay.

Anchorseal on my lumber order today. Grace Vycor for the joists also on order.

I fully plan for this deck to be the only thing that survives a meteor strike to the house
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