Oversized notching

[^woody^]

Don’t inspect notches? So why do we pay for there service!? The floor falls through who’s liable….

Liability is with the contractor you contracted with to do the work to the standard you agreed.

You are not paying inspectors to go around with a microscope inspecting everything, nor are they expected to.

 

[big-all]

Some of the things you see in real world. Downlight notched into a 100mm joist only 25mm left of the joist!
Soilpipe bend notched into 9 " joist not much left of joist. Many of these new linear shower wastes require carving the joists up. Never seen a structural failure though.

the way it works

you reduce far far to much it will sag
the load then transfers via flooring or other timbers mid-span till they sag a bit and take some off the load thus reducing the load on the weakened timber
now the weakened joist can fully fail and transfer load to parallel timbers and its not until they cannot support the extra load or displace some load to elsewhere and fail that you will probably notice
wood tends to groan/cracked /bang as it suffers the louder and more often the greater the danger

 

[tony1851]

shear stress would be 0.5N/mm2 whilst allowable is 7N/mm2 so theoretically structurally OK for shear

Decimal point missing!?

 

[Dereekoo]

Decimal point missing!?

Yes, thanks Tony

 

[noseall]

Many of these new linear shower wastes require carving the joists up

There is no shower on the planet that justifies weakening multiples (or even single) joists. Install another shower tray with a different waste position.

 

[Deleted member 174758]

Many of these new linear shower wastes require carving the joists up. Never seen a structural failure though.

So far... But I have rejoisted a number of rooms where after decades of hole boring, notching out and genersl abuse (by trades who should know better) collapse was imminent. As a consequence my pet hate combinations are plumbers and old buildings, electricians and old buildings and electricians and any form of suspended/false ceiling which is metal framed.