My client’s 1920’s house has the main floor 2″X12″ floor joists notched out 8″ to house the main beams (to maximize head room I presume). Each floor joist is now cracked as a result of being reduced in size due to the large notches. I was thinking of adding plywood gussets to each side of the joists at the notches to prevent further weakening of the joists. Are there better alternatives or am I on the right track? Any input would be valued.
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How about adding hangers instead?
Seems like that would be a lot easier...
I don't mind anyone owning firearms. Just give me all the ammunition.
Absolutely go with the hangers. They're designed to do this job. If this ever gets inspected, hangers pass but plywood patches are an unknown. They may even be stronger, but there's no way to prove it. Inspectors go with certainty, they reject the unknown. Being a 1920's structure, the two by will be a full 2" thick, so order the Simpson hangers with the -R suffix on the part numbers for the full Rough dimension version. I think it's http://www.strongtie.com for their web site. And jack things up so the cracks are closed and the hangers are really carrying the load before you nail them home.
-- J.S.
If the bottom of the beams and joist are all flush with each other, you may be able he shear the underside of the joist with plywood. To make more stronger, prestress/jackup the plywood before nailing or screwing. Gluing and thicker plywood makes it stronger.
I repaired one just like this last winter. used joist hangers for most of it. I assume you have full rough cut two bys. They make sizes to fit them and you can get doubles too, if you have sistered pieces.
I also found two or three places where wires or plumbing preceded me and it was better in those lacations to sister with adhesive glue and plywood gussets.
Regardless of which method (the hardware option is far less expensive and easier and better) I'd recommend using a jack to get the load up where you have a split
Excellence is its own reward!
Wires and plumbing are definitely an issue in many spots in this basement. I think that I will use a variety of techniques that have been suggested in this forum. I don't need to jack the beam(s) a great deal but I do want to address the cracks at the notches.
Thanks for the advice
I'm not a big fan of joist hangers--they didn't have 'em back in the mezostoic era when I learned to swing a stone lashed to a sabre-toothed tiger's legbone--but they'll probably do the job okay.
A better way, IMHO, is to put a 2x4 ledger on both faces of the beam under the joists; glue it on with structural adhesive and sock it down with ¨ü" lag screws and big washers directly under each joist. This will take the load completely off the notched section and you should be able to jack up the beam afterwards and lift all the joists with it to get the floors level. Place some adjustable screw-jacks or new 6x6 posts to support the beam at the new height above floor, and you're outta there. Once you re-adjust all the doors in the interior walls, I mean, and patch the cracked plaster, and....
Two important caveats when jacking:
1. Check the floor against which your jack will be pushing down. In old buildings like that, it's hard to know if the basement slab is thick enough to resist busting before you manage to lift the first floor (and the second floor and the roof) when you start cranking on a powerful jack. Best bet will be to spread the load under the foot of each jack; either sit it on the side of a piece of 8x8 at least a couple or three feet long, or build a butt plate from two 12x12 pieces of 3/4" plywood sandwiched around a piece of 1/4" steel plate.
2. Lift slowly. If you're gonna take a 90-year-old lady out dancing for the first time in years, you don't want to start her off doing the Beer Barrel Polka....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Edited 6/13/2003 11:58:35 PM ET by Dinosaur
Thank you for your timely advice on my floor joist problem. I like the ledger idea. I don't have to jack the beam(s) a great deal at this point. My main concern was to halt or limit the cracking in the joists.
You have given me food for thought.
Thanks Dwhite
No problem.
Remember that even if the floor is close to flat & level already, you will still have to jack the beam up a bit to transfer the load onto the ledgers once they are installed. You can probably lift enough to do that with 4'-8' adjustable screw-post jacks and a big crescent wrench. I think it will be easier to do it that way than to put in temporary beams and jack up the joists, then install the ledger, and then lower the joists onto them. If you've got just a few joists that have sunk more than you can tolerate, those ones you should jack up before installing the ledger.Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
>...., and patch the cracked plaster, and....
What I've found helps a lot is to pull the baseboards right above the area to be jacked, and rake out the bottom of the plaster to maybe 1/2" or so above the top of the sole plate. This reduces transfer of stress to the old plaster and you get less cracking. But of course you have the work of pulling and replacing the baseboards as a tradeoff.
-- J.S.