Repair Detail for Notched Floor Joists (photo)
Repair Detail for Notched Floor Joists (photo)
(OP)
I attached a photo, for a situation I'm facing in trying to help a friend with some home renovations. For the record, I'm a structural engineer with a P.E. but I don't have a ton of wood experience beyond what was needed for the P.E. exam.
Basically, I was just curious if others on here would tackle this by designing a repair detail w/ plywood side plates (can only access the joists from one side... ) or is the notching so extensive you'd just recommend sistering with a brand new joist?
The reason there is only access from one side is due to the fact that there is another joist (8" deep) from when this was originally an attic rafter. Someone made the 2nd floor living space so they added new 10" deep joists (the badly notched ones in the photo). In some cases there is a gap between the two, otherwise my approach might have been just nailing the two joists together.

Basically, I was just curious if others on here would tackle this by designing a repair detail w/ plywood side plates (can only access the joists from one side... ) or is the notching so extensive you'd just recommend sistering with a brand new joist?
The reason there is only access from one side is due to the fact that there is another joist (8" deep) from when this was originally an attic rafter. Someone made the 2nd floor living space so they added new 10" deep joists (the badly notched ones in the photo). In some cases there is a gap between the two, otherwise my approach might have been just nailing the two joists together.







RE: Repair Detail for Notched Floor Joists (photo)
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Repair Detail for Notched Floor Joists (photo)
At the supports where shear resistance also is missing, and perhaps at other areas, attach an angle under and alongside the joist. To get the angle under and alongside where joist is let in to wood, use a flush cut power tool to make slots for the angle to get in there. At any area where that won't work, shelf angles can be attached to the support (steel of concrete). At joist hangers a little thin metal welding may be in order.
RE: Repair Detail for Notched Floor Joists (photo)
RE: Repair Detail for Notched Floor Joists (photo)
It's probably too much to ask but if possible it would be good to jack up each beam prior to sistering on a new joist. If that's unfeasible then reduce the load on the above floor to a minimum when sistering on the joists.
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Repair Detail for Notched Floor Joists (photo)
The steel strap will work if you can somehow preload it. It is also very sensitive to hole sizes and slip. For me, getting the steel to stretch makes this option a bit too complicated. If you just need to feel good then maybe the steel strap will suffice. Just expect a decent amount of deflection before it engages.
RE: Repair Detail for Notched Floor Joists (photo)
Was this hidden by a ceiling until just recently?
It looks kind of old shallow joists are alternated with new, often repeatedly deeply notched joists.
Then again sometimes the old ones look to have been marked for the deep notches, but spared the indignity.
And the new ones are not centered in each joist bay, but offset and kind of close to an existing old joist.
I'd sure like to know the back story.
What size "perfect" joists would be required for the span, , etc?
RE: Repair Detail for Notched Floor Joists (photo)
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RE: Repair Detail for Notched Floor Joists (photo)
Mike McCann, PE, SE (WA)
RE: Repair Detail for Notched Floor Joists (photo)
Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries
www.americanconcrete.com
RE: Repair Detail for Notched Floor Joists (photo)
Please remember: we're not all guys!
RE: Repair Detail for Notched Floor Joists (photo)
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Repair Detail for Notched Floor Joists (photo)
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Repair Detail for Notched Floor Joists (photo)
RE: Repair Detail for Notched Floor Joists (photo)
The other reason is that it would be hard (and risky) to create a one-size fits all detail, meanwhile, you billing at $100 an hour to investigate can pay for a lot of new wood beams.
Good luck!
RE: Repair Detail for Notched Floor Joists (photo)
cool
I might add this photo to my se's house of horrors. A bit off point, but I'm wondering what trade this workmanship hails from? I had 22" beefy Ijoists supporting office floor loads in a 3 story and the electrician needed to run conduit from here to there. Rather than run perp to joists poking a 3" hole in the IJoist web and then 90 degree curve turning to the box, he went direct and chain-sawed 3" x 40" slots through bays of floor joists. Had to admire his.., um.., well, something I'm sure.
Although I truly love the alternative exotic and outta da box, I'd keep this one in the family, and sister it up.
RE: Repair Detail for Notched Floor Joists (photo)