On 26/06/2019 19:47, DerbyBorn wrote:
John Rumm wrote in
o.uk:

On 26/06/2019 18:17, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the
regs tells me that in a 20cm Joist the max hole can be 32mm

I need to pass a pipe of 42mm diameter!

The joist is right next to a wall at the outer edge of the house -
load on it will never be high.

Pragmatically - would you go ahead and bore the hole?

Yes.

(noting a hole in the centre is better mid span, and a notch better
near the ends)



I now reckon I am okay up to 50mm on a 200mm deep joist:

https://www.labc.co.uk/news/how-get-...-solid-timber-
joists

I was going to say what John said. But that link looks pretty good to me!