Suggestions on floor joist sag?

It's a little difficult to describe this without pictures, but, I'll try.
25 year old home. Very "open concept".
Stair wells run perpendicular to floor joists. One side of well is a bearing wall. Other side of well has no wall. Joists are cut at the well ("cripple joists?"), with a header. The header simply butt nails into double joists at both ends of the well.
The double joists have rolled slightly (outward at the bottom, despite having full width blocking to the next joists). Leaves about a 3/8" gap between the bottom corner of the header and the double joists.
The nails have bent, and the ends of the header have sagged about 3/8", separating from the subfloor.
Most of the load on the header is the floor loading itself.
Preparatory for doing the ceiling in the basement, I'd like to get the header ends back into line and the joint reinforced.
The first step would be to rent a jackpost and push the header ends back into line.
Then what?
How to pull the double joists out of their roll to tighten the gap?
I could bore big lagscrews in thru the double joists into the ends of the header, but that's end grain and may not unroll the joists. I'm not fond of drilling end-grain on 2x like that.
Lots of massive screws "toed-in" wouldn't hold.
Heavy duty angle mending plate?
thanks.
--
Chris Lewis, Una confibula non set est
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"Chris Lewis" wrote in message

Hard for me to get a vision of the exact problem. I'll give some advice which may or may not apply, once you get everything where it belongs.
On the header, instead of a mending plate I would use double joist hangers. Simpson makes them.
Speaking of hangers, if your joists are just nailed (toe or other) at the header, I would throw a hanger on each one of the joists.
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Your discription is hard to follow , but you have serious design weeknesess. A few new concrete piers and jacks ,and a good architect wood cure it. Or New adjustable jacks on separate new piers. Load it slowly , Level it over weeks. or months. then fix all the cracks in the walls
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snipped-for-privacy@nortelnetworks.com (Chris Lewis) wrote in message

I'd definitely use the joist hangers Gunner mentions. Every joist end that is supported by the double joist header need adequate support and connection to the header. The header needs similar support. The headers and joists should be forced back to vertical firs. I would check the far end of the supported joists to make sure they haven't been pulled loose. Look for cracks at the wall / ceiling intersection.
Tom Baker
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Joist hangers will not do any good to take the roll out of the header joists.
I would get some 3x3x 1/4 angle iron clips made. Have them punched both directions. Install to the header joist with through bolts or all thread, I/m thinking 1/2" or 5/8" all thread. Don't try to install them flush on the ends of the header joists, hold them off the ends a bit so that they really pull. Drill through the double joists and draw things back into position.
Hope this helps.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG

I'll try.

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joists.
after them.
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