Flight structure settings (in context of US residential wood frame stair)

[proto]

In the stair settings dialog, under "flight structure settings", I have been choosing monolithic stair as a generic stair starter because it gives me a shape closest to what I expect in section. But I am just confounded by the "remaining stringer size" setting immediately underneath this flight structure type.

How is this setting actually useful?

I sort of get that it identifies the meat of the stringer remaining once the stair is cut, but how is that useful as a stair design driver?!? Would it not be more useful to select a stringer size & have the settings create the appropriate remaining shape?

Assuming a 2x12 stringer with 3/4 finish material at the tread & riser, for instance...this "remaining stringer" number changes with every change in the Rise/Run settings and yet it's not a part of the parametricity of the tool.

What are people doing for a generic residential straight run stair based on 2x12 framing?

Should I just ignore this until I have actual calcs sizing framing later in the project?

(it just grates on me every time I see it, but maybe i'm just not understanding how this should be used or what alternative strategy of creating simple stairs I should be using)

thanks for your perspectives up front

[Barry Kelly]

You want the 'Beam' flight and landing structure, not monolithic.

You can have multiple beams.

Barry.

[Barry Kelly]

OK, I am not sure what the reason for that would be.

All I can think of would be to try a different browser.

Unless something has happened to the community that is not affecting me.

@Lingwisyer , can you edit your posts?

Barry.

[proto]

I see the same silly number that has nothing to do with how the stair will be framed

surely this has been addressed before?

what am I missing?

[proto]

[proto]

it's safari that's the problem child...i just tried chrome & i can edit posts in chrome

[Barry Kelly]

I am not sure I see your issue.

It is the height of the beam under the stair.

The treads and risers will be where you want them to be and you are placing a beam under the stair.

How deep you want that beam to be under the treads and risers, that is what you are setting.

I guess you could look at it as the 'structural' depth of the beam.

Or are you expecting the height of that stringer to include the wedge under the treads?

Barry.

[proto]

Yes, per the image in my OP post. That “beam” dimension has nothing to do with how residential wood framed stairs are constructed. Additionally, that number changes every time the rise/run changes.

A framer cuts down a 2x12 or 2x14 & creates the stair with multiple stringers, similar to the second image in my most recent post above. It is a subtractive process and isn’t dependent on a minimum beam [structurally/numerically it is, but that is resolved during calcs by how many stringers & whether they end up getting doubled or tripled even]

But the geometry is based on a fixed depth for the diagonal stringer member, not a beam + wedge geometry.

[Barry Kelly]

---

@Barry Kelly wrote:

Or are you expecting the height of that stringer to include the wedge under the treads?

---

I should have looked back at your first image.

That does seem to be how you want to measure it.

As you can see in your first image it is affected by the tread/riser sizes and the inclination of the flight.

As I mentioned it is really the structural depth of the beam.

Ignore the wedges under the treads as they would add little no no strength to the stringer.

If it was a steel beam, it is this depth you would want and the wedges would be welded on.

Timber is a little different if you are cutting the notches out., rather than adding the wedges.

So the wish should be that the 'open stringer' beam structure should have an option to set the structural beam depth and/or the overall beam depth.

I guess all you can do for now is place the beam, 5 or 6 inches deep and then do a quick measurement in section to check that you can cut it from a 12 inch piece of timber.

Barry.

[proto]

What I’m asking about is an exceptionally common stair building mindset for wood framed construction (commercial or residential). I’m surprised there isn’t a parametric typology for it in archicad. By version 26 no less…

[Lingwisyer]

Do note that this is all part of objects that are loaded by the Stair Tool and maybe localisation specific. So if GS are the ones to "eventually" update it, hopefully it's global.

Gosh, the macro for it is long...