Plumber over-notched the joist. Plywood repair?
I have an 100 year old house, we wanted to put in a 2 piece bath. However, the area where it was to be installed needed joist repair; it had to be sistered with 2 x 10’s at the full width. That went all fine; including headering off a boxed area for the plumbing and drain.
I knew the stack was likely going to get drilled out through one of the nearby joist to bring it up through the wall. I don’t know what but apparently the plumber went way high on the initial 2 3/4″ inch (approx) hole and put the top within 3/4″ of an inch of the top of the joist. Then later realized, he was too high and made the notch bigger notch below it.
Can this be resupported with an 3/4″ plywood gusset on either side of the space? The over-notching occurred on the sistered joists (one of which in an extra 1/2″ in width & height as its the original joist).
If so, would it be acceptable to fasten to bottom at 6 1/2″ (water lines are in the way) height of joist for a span of 8″ with a “U” shaped notch for stack pipe (7″ if it won’t fit it in the crawl space access). Currently, full height the inner side of the drain box frame would only have 14.5″ long gusset. I can see it being a little undersized, so I’m considering placing a concrete block with an adjustable jack on top to compensate as well.
Cheers,
Mike
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Replies
Here is a drawing if the current notching,
Reattaching
Mike,
Here is a summary of joist-notching and joist-drilling rules, courtesy of Paul Fissette (via JLC): "The rule that most codes use is that holes can’t be any closer than 2 inches from the top or bottom of the joist, and cannot be within 2 inches of any other hole. If the joist is notched, you can’t drill the hole within 2 inches of the notch. The hole’s diameter can’t exceed one-third of the joist depth. ... Notches in the top or bottom of a joist can’t exceed one-sixth the depth of the joist and can’t be longer than one-third the joist depth. Notches must not be made in the middle third of the span. If a notch is made at the very end of the joist, it can’t exceed one-quarter the joist depth."
Any repair you make has to satisfy your local building inspector. Many building inspectors require an engineer to design such a repair, so check with your local inspector before proceeding.
One possible product to consider (if approved by your local inspector) is the Metwood Joist Reinforcer.