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Are these joists at risk now?

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What do the pro's here think about this?
To me it looks like way too much has been removed from the joists & they are weakened.

(Fyi not my work, not current work but from someone I was looking to hire).

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Thats as close as I have, its taken from another site.
 
That looks like a 40mm waste pipe, at least 10mm below the top, which is way over what you’re theoretically meant to take out, and probably would be even if it was a 32mm pipe. Looks like at least an 8” joist.
See it done all the time tho. Guess it depends on whether it was his call or he was told to do it, etc… wouldn’t necessarily write him off based on that pic
 
Whether or not its a serious issue depends on a) the depth of the cut; b) the depth of the joist and c) the span of the joists.
Can't really tell much of that from the pic. Usually a notch near the end of the span is not as critical as one nearer the centre of the span.
 
OK cheers folks, so not a clear "do not do it".
 
Hammer a tight cut of batten into the top of every notch, and glue and screw the board down that goes over the top of it

And tell him next time, make the holes on the joist centre line, even if it means having to thread the pipe through from outside/adjacent room where joists go the other way, or in sections that are coupled up
 
OK cheers folks, so not a clear "do not do it".
I wouldn’t write off the plumber based on that, he may as others have said done it under sufferance

It looks like the pic shown could’ve been sorted out with a trimmer

There are building regs rules

IMG_0171.jpeg
 
The work looks neat and it looks like chipboard so once that is back down a lot of compression resistance will be restored anyway. I suppose he could have taken the waste towards the wall to lessen the effect of the notches but it would be a small "improvement". He has kept a decent gap between waste and water.

What is sure is that there are very much uglier examples of plumber butchery of joists around.

Finally the point of the given diagram is not "this is all you can do and anything outside these limits is wrong". It is merely that there is no need to prove anything within these limits: everything is deemed structurally ok. So a 75 notch in a 200 joist looks much worse at first sight than a 25 notch in a 150 but if the 200 only needed to be 150 due too its span then thay are the same thing. Bathroom joists frequently wind up deeper that they strictly need be due to wall layouts.
 
For me, it's not so much that he's done it, but rather how excessively deep. He's probably skimping on fall as well and it still looks close to being halfway down the joist at the end.

He could have notched them far more precisely using his fancy multi tool, or even notched out some of the underside of the flooring at the top end (a few passes with his little wizzy saw would have done it).

As said, we don't know the span etc but given the socket in the corner it looks to be a new ensuite in an existing bedroom so presumably stud walls, tiles and sanitary ware to be piled on as well.
 

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