Floor Opening for Basement Stairs Done Wrong

[Syd Flash]

The opening for my basement stairs was framed incorrectly.

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For one, there is a cut in the double joist. Even worse, the 2nd floor stairs, which are right above, are not supported by the header.

I cannot sister new joists to the outside that span from the beam to the sill as there are utilities on one side and only about 4 inches to the next joist on the other.

My idea was this: 28121

I would like to know what others think.

Am I better off going with posts? Does doing so change the code req for a double joist?

How much of the end of the stringer should be resting on the header?

Any other ideas?

Thanks for any help!

[Syd Flash]

I should explain my proposed fix a bit: I was thinking of removing the three 2x8's and replacing them with two 2x12's - this would give me a quad 2x12 header - which I could then support with a quad 2x10 joist hanger - can't find a quad 2x12 hanger - which would transfer the load to the joists which are now bolted and nailed together.

[John Kogel]

That looks like it will do fine. Why were the 2X8's added? It looks like someone was shifting the stairs over a few inches for clearance?

The stringer should go full height, that is, the top step rests on the stringers and is level with the floor. Remember to take flooring into account so everything is flush or close to it.

[Syd Flash]

Thanks John!

My guess is that the 2x8's were added when the stringer didn't reach the header of the floor opening during the original construction.

As for the stringers, what I was trying to ask was: how much of the end of the stringer needs to be supported? Would this be okay:

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Thanks again!

[Jim Luttrall]

Maybe I am missing your point but the drawing does not seem to do anything to provide support at the cut joist.

The connection is not the problem, it is the cut joist where it should be full length. I can't see a way to fix that without taking it out and putting in full length, un-cut joists.
A single joist cannot support the load unless proven by an engineer with a designed repair. with the weight of the second story stairs, you may even need a triple joist.

Yes, posts could be used to provide direct support but that would likely encroach on the stair width, a big no-no unless the stairs are much wider than I envision.

[John Kogel]

What Jim said. I thought you were going down from there. I see now the base of the stringers rests on that header. The heels of the stringers need support, or they can just split off and send somebody to their death.

You might want to look into a steel girder to carry the weight over to the walls of the basement. Otherwise, double up those joists by moving plumbing and ducts. Through bolts with nuts and washers.

[Syd Flash]

Thanks for the replies!

Can the load path of the cut joist be fixed by adding an outside sister X number of feet beyond the cut?

I have seen this suggested elsewhere (seen both 2' and 4' beyond the cut suggested) but can't seem to confirm it.

If doing so will fix the load path: Does it matter if the sister is on the outside of the non-cut joist?

Anyone have a rough idea what an engineer would charge?

Also, what is the desired with of the staircase?

Thanks again!

[Lon Henderson]

Good advice from John and Jim.......You can probably get an engineer or architect opinion for around $250. A good handyman may can help you actually do a proper repair for around the same price.

But on an unrelated subject, nice graphics. What software did you use to make those?

[BridgeMan]

I'm a licensed engineer, and only charge $50 an hour. Care to fly me out to NH for a quick look?

Oh wait. I'm not licensed in NH. Forget my offer.

[Syd Flash]

For the graphics, I kinda hackd at them with Pixelmator for Mac. I search in Google for an image similar to what I am thinking and then edit them for my own devices.

Any input on sistering? Does it have to be sill to beam, or can it be smaller? I've seen this called scabbing...

[Jim Luttrall]

Proper repair is from bearing to bearing. Lots of weight and movement there, don't cheap out or try to short cut.
Your diagram indicates only one joist on each side of the stair is actually carrying the load of the entire floor and stairway above. See red circle
The rest of the doubled, tripled, joist hangers, etc. is just blocking.
It may take some of the bounce out of the floor but it does nothing to add bearing capacity to the joist that is there.
At a minimum, remove the cut joist and replace with full length and full depth joist then use metal hanger brackets to support the headers.

But getting a design from an engineer will be money well spent.

Of course this is not rocket science and there are standard methods to do this correctly. Find and old school carpenter that knows how to frame a stairway using a carpenters square rather than a "house assembler" found on most tract home sights.

[Syd Flash]

Decided to replace the cut joists and re-do the headers with hangers to keep everything in place.

New problem tho - The joists in my basement measure between 10 7/8" and 11" wide - far from today's standard 11 1/4" - do I need to rip the new joists down or do I notch them at the sill and beam?