Underside notches on every joist!

[piggoy]

In the past a "plumber" has run a pair of 15mm copper pipe from one side of the room to the other in the ceiling and notched every single joist on the underside to a depth of 1.5 inches. The notches are about 8 inches from the ends of the joist where they rest on an RSJ. The joists are 8x2'' with a span of 4m. The building regs state that notches on the underside of joists are a big no no. Realistically is this a major problem that should be remedied? I suspect this work was done about 5-6 years ago by the previous owner. The floor doesn't appear bouncy or springy from above.

Thanks

 

[dhutch]

Cant comment beyond saying it would have been a lot worse if they where in the middle of the bead (middle of length that is, obviously holes are what you want ideally...)


Daniel

 

[tony1851]

The building regs state that notches on the underside of joists are a big no no.

No; there are no Building Regs prohibiting notching the underside of floor joists.

If they are only 1.5" deep, the joist is effectively 6.5" deep at that point. Being so near the bearing, this will not be a problem.

 

[piggoy]

The building regs state that notches on the underside of joists are a big no no.

No; there are no Building Regs prohibiting notching the underside of floor joists.

If they are only 1.5" deep, the joist is effectively 6.5" deep at that point. Being so near the bearing, this will not be a problem.

Really? What about this document?
http://www.charnwood.gov.uk/files/d...joists/Notches and Holes in Timber Joists.pdf

 

[footprints]

As I recall from my days dealing with gas regs "Should" means just that good practice. Shall on the other hand means they will string you from a lamp post if you ignore it!

Link says Should, so that might explain the conflict of opinions.

 

[tony1851]

Really? What about this document?
http://www.charnwood.gov.uk/files/d...otches and Holes in Timber Joists.pdf[/QUOTE]


Those are 'rules of thumb' with a high margin of safety to allow for the few idiots who go hacking away at joists.

In purely structural terms, notching to the extent of the OPs case will not be a problem. A notch near the end of the joist has zero effect on the bending stress, which is greatest near the middle.

The only effect a notch has in that position is to increase the shear stress at the bearing. But shear stress in domestic joists is never a problem because they are relatively lightly-loaded.

The OP will not have a problem with the notch in that position. In contrast, if it was near the middle, then it would have reduced the effective depth to 6.5" - and on a 4m span that would give problems.