# Hang bottom of stair stringers below floor with joist hangars?



## nuclearnerd (Dec 20, 2010)

I'm trying to maximize the headroom under a new flight of stairs (above an existing flight of stairs) in a remodel of an old house. Usually you would set the entire bottom of the first step on the subfloor like this:










But doing so makes the ceiling of the stairway below drop suddenly where the stringers meet the floor joists. I'm wondering if, instead, I could support the stringers from the side of the floor joist using a joist hanger. That would give me more headroom, and would look something like this:










(Only with joist hangers off to the right of the floor joists, instead of the notches shown). Has anyone framed stairs this way?


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## nuclearnerd (Dec 20, 2010)

Here's another view of what I'm thinking of. I haven't found many other examples online:
http://www.pic.stairs4u.com/splitlevel/cut_lower_stair_stringer.htm
http://www.pic.stairs4u.com/splitlevel/stingers_connected_to_landing.htm


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## Willie T (Jan 29, 2009)

Frankly? Totally stupid. This "method" (if you want to call it that) offers almost NO support in the direction the forces will be exerting themselves.


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## nuclearnerd (Dec 20, 2010)

Really? The forces are primarily down. Joist hangers can take care of that I would think. I'm more worried about the joist with hangers twisting due to the off-center load, but with a solid joist hanger, the stringers themselves will help that.

Unfortunately I have to come up with a way to increase headroom. The old stairs were grandfathered, but now that I've started renos (started with some minor work on the stair landing), my inspector is demanding that the headroom be increased to meet code (6'6").


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## Willie T (Jan 29, 2009)

No, the forces are not just down. They are pivoted at the upper stringer attachment, and swing forward, toward that 8' hole... pulling away from those hangers, and progressively drawing the hanger nails slowly out of the lower platform side.


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## Willie T (Jan 29, 2009)

nuclearnerd said:


> Unfortunately I have to come up with a way to increase headroom. The old stairs were grandfathered, but now that I've started renos (started with some minor work on the stair landing), my inspector is demanding that the headroom be increased to meet code (6'6").


About the only way is to cut more out of the top floor, and shift the entire stairs forward.


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## nuclearnerd (Dec 20, 2010)

I see where you're coming from Willie. But if there were no gap between the hanger and the bottom of the stringer, then there would be no room to rotate before the hanger pulls upward and stops the rotation. Think of it this way. For the bottom of the stringer to rotate outwards (once it is seated on the hanger), The stair opening would have to increase by 1.5" (seems unlikely), or the top of the stringer would have to push upwards. That's not going to happen when the load is pushing down.

In fact, if the upper hanger were slightly loose, there would be a force *into* the lower joist, as the stringer tried to rotate about the bottom hanger. This is why you have to install a "kicker" when setting the stringer on top of the sub floor.


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## nuclearnerd (Dec 20, 2010)

Willie T said:


> About the only way is to cut more out of the top floor, and shift the entire stairs forward.


There's another floor joist above the upper stairs. If I shift the stairs forward to get headroom below, I loose too much above


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## nuclearnerd (Dec 20, 2010)

Another option could be to hang the stringer off the stud walls beside (with lag bolts maybe), but I'm even less comfortable about that idea.


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## Willie T (Jan 29, 2009)

Like the man says, "You'll be walking on it, not me." :thumbsup:


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## Keith Mathewson (Sep 1, 2010)

I can't really see because there is a "bleep bleep bleeping" ad for Home Depot right in the middle of the pic but it sounds like you need a hanger board.


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## Keith Mathewson (Sep 1, 2010)

nuclearnerd said:


> Unfortunately I have to come up with a way to increase headroom. The old stairs were grandfathered, but now that I've started renos (started with some minor work on the stair landing), my inspector is demanding that the headroom be increased to meet code (6'6").


Your inspector is wrong, as long as you are not reconfiguring the dimensions of the stair-hole the older standards are applied.


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## MTN REMODEL LLC (Sep 11, 2010)

Keith Mathewson said:


> I can't really see because there is a "bleep bleep bleeping" ad for Home Depot right in the middle of the pic but it sounds like *you need a hanger board*.


Keith... Could you explain that assembly?? How it's differnet than OP is proposing.

TIA


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## Willie T (Jan 29, 2009)

A hanger board? I thought he was wanting to somehow anchor the BOTTOM, not the TOP.

Hanger boards are at the top, are they not?


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## Willie T (Jan 29, 2009)

As far as whether the inspector is right or wrong....... well that depends upon the years of repeated hassle you want to set yourself up for.

You can win today's battle, (maybe), but the wounds you will suffer, (repeatedly), for years, is hardly worth it.


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## MTN REMODEL LLC (Sep 11, 2010)

Willie T said:


> A hanger board? I thought he was wanting to somehow anchor the BOTTOM, not the TOP.
> 
> Hanger boards are at the top, are they not?


I thought so also.... but it is the same idea the OP wnats to do on the bottom... I think.


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## Willie T (Jan 29, 2009)

MTN REMODEL LLC said:


> I thought so also.... but it is the same idea the OP wnats to do on the bottom... I think.


Except that instead of pushing against a braced board, you would be pulling away from an un-braced board.


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## MTN REMODEL LLC (Sep 11, 2010)

MTN REMODEL LLC said:


> Keith... Could you explain that assembly?? How it's differnet than OP is proposing.
> 
> TIA


Yes Willie.... Maybe Keith will come back and explain the assembly.


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## Keith Mathewson (Sep 1, 2010)

I was able to resize the pic enough that I now think I know what is being asked.
As Willie said, NO you cannot use joist hangers for the first riser connection. The forces are NOT straight down, they are pulling the stringer away from the landing. 

The hanger board is indeed for the top riser connection. However if goal is to increase headroom on the underside of the stair for the flight below you should consider a housed stringer stair. You could move the underside of the stair up at least 4".


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## kwikfishron (Mar 11, 2010)

I'd be looking for a way to extend that floor so the stringer has something to sit on.


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