Joists with 65% notches!

[iwilson16]

I have two floors of an old Victorian/Edwardian townhouse, where I have a bathroom on each floor. The waste pipes run up the corner of the building, and to allow for this one of the joists terminates in a small joist at 45 degrees to the other joists. Seen here:



There are several issues here.

1. The left hand end of the angles mini joist is *not* supported by the wall (as I suspect it should be).
2. The angled joist *and* the joist second from left have extreme notches cut in them to allow for the upper shower waste. There is only 80mm remaining of the 225x75 joist!

This shows the left end of the mini joist:


This shows the notches:



How bad is this? Should I be overly concerned?

I plan to replace the lower bathroom first (soon), and will install a dropped ceiling so that the waste pipes can be routed under the joists. That will let me repair the main notched joist.

What size and length of joist should I use to sister the main joist when repairing it?

I'll probably need to remove the angled joist in order to get holes drilled and botls into the main joist, so I may as well replace it with a slightly longer joist so that the left end rests in the wall.

Would I need a prop to support the cantilevered joist? The toilet and WHB of the upper bathroom are directly above this joists, so its not possible to walk directly above it. Its possible the floorboards are supporting it to some extent.

Any other advice appreciated.

Thanks
Ian

 

[23vc]

Its possible the floorboards are supporting it to some extent.

Yeah, that last joist looks like it's entirely supported by the floorboards at that end. You're on the right lines to fix it, new joist of same size or most similar modern equivalent size, all bolted together, bearing into the brickwork etc. Current setup does look pretty dodgy!

 

[John D v2.0]

well, at least they got the correct fall on the waste....
Anyway that's pretty bad, The good news is it's unlikely to snap but it would cause a lot more deflection than there should be.
We had a lot of incorrect notching, a 40mm waste going through 7 inch joists with around 50% notching almost mid span. The floor was very bouncy and a lot of the herringbone strutting between joists was missing, I think previous plumbers had assumed the joists and strutting were purely decorative.
My method of improvement was to remove all the pipes and route them sensibly, the ensuite shower is on a plinth now which is not ideal but this to avoids boxing the pipes in to the ceiling in the lounge. And the damaged joists, I cut strips of structural ply slightly shallower than the joists, attached herringbone struts to the cut pieces, screwed and glued to the sides of the existing joists, and screwed the struts in place. from the top. But it was a lot of work for a novice like me.