Handbasin waste pipe route/slope

[jase the space]

I am adding a new upstairs cloakroom to my house. I need to add a handbasin and will be concealing the copper water pipes and plastic waste pipe (32mm) in a partition wall (don't have the luxury of an outside wall!).

This means that the waste will have to drop vertically inside the partition wall until it gets below floor level (<1m drop) before it will then have a gental slope to the outside wall (~2m away) in the void between ground floor ceiling and upstairs floor.

Is this short vertical drop OK or does it contravene regs? I can possibly put a bit of gradient on this drop but not a lot. Is a 90deg elbow between vertical and horizontal runs OK or will I need a radius bend?

Any help muchly appreciated!

 

[bathjobby]

Thats ok, the 2m horizontal pipe after the vertical should stop the vertical syphoning the basin trap. Remember that all pipe connections should be accessible, just as accessible as under flooring

 

[Nige F]

90 degree elbow Radius bends Use a HepVO waste valve inch and a quater in place of trap, and you`ll never get any smells back ,or gurgling

 

[jase the space]

I have ordered a HepVO waste - can this be installed in addition to a bottle trap? The reason I want to do this is a chrome plated trap will finish off the basin nicely. If there may be issues with this type of trap then I can also put the HepVO in-line - will this work?

As I mentioned in my original post I will have a vertical drop of ~1m followed by a gentle horizontal slope of ~2m to the outside. I was then going to have a further gentle slope to a new soil stack but there may be problems with this - a new toilet soil pipe will enter the main stack at around the same height or even slightly higher than where the basin waste would enter. Not sure I can plump in the basin waste here.

The alternative is to have a vertical drop from where the basin waste exits the building (after a short gentle horizontal slope) to an existing gully trap. Will there be issues with this?

 

[ChrisR]

No point using two traps. Either route you suggest would be ok, as you say you have to be careful about joining two pipes to a stack in the same area, but the fittings would have blanks for connecting bosses.
I don't suppose you'll have trouble but for that length of pipe you should be using 1 1/2" (40mm) pipe.

 

[jase the space]

Thanks for the reply.

Would there be any benefit in connecting 40mm pipe to a 32mm trap via a suitable coupler? Both traps I have ordered are 32mm.

Cheers

 

[ChrisR]

You'l need a 32mm trap cos a 40mm won't fit a basin! MAx length for 32mm is 1.2 metres if I remember right. You have a good fall overall so shouldn't have a problem, but if you haven't bought the pipe yes use 40mm.