Kitchen sink waste 40mm to 32mm

[CJRatch]

Hi guys thanks for your time.

Ive just core drilled a hole for my kitchen sink waste stupidly my holes dont line up perfect enough to fit a 40mm waste however a 32mm will fit through.

Are there any regs against or repocutions to running my kitchen waste in 40mm solvent to the cored hole then 40mm to 32mm on the 350mm section which goes through the wall? Will there be much slow up on the drainage?

If so I'll have to try get in with hammer and chisel open the hole a bit more sigh.

Thanks.
Chris

 

[CJRatch]

Having red that may not pass building regs Ive just chiseled it out. The holes not quite as pretty as I wanted but nothing a bit of mortar wont sort out.

Cheers!

 

[John D v2.0]

Yeah just to answer your original point don't do it! It's the perfect place for everything to get stuck so you'd be forever unblocking it. Even keeping it 32mm from the sink outlet would be better than narrowing it later.