Hi to All

duffsparky · Oct 4, 2010

Hi from a newbie to this forum🙂

I'm a sparks and been so for coming up 30 years; (sh*t) that's a long time, makes me feel old.

With work being in short supply I've turned to some DIY in my own house; I hope, like many, things will pick up soon.

Not sure if I should post here for the advice I'm after, but not doubt someone will put me right if it's in the wrong place.

Anyway, I'm revamping our downstairs toilet and installing a shower at the same time. I need some advice on getting the plumbing waste correct and would appreciate any help offered. Below is a drawing of the new system not yet installed in the shower room/toilet along with the existing in the kitchen.

Obviously I need to make sure all the pipe sizes and falls are correct, coz I don't want to do it again. Due to subsidence the floor in the shower room/toilet has to be replaced. I've dug all the old concrete and backfill out and I'm back up to the sand blinding layer so far.

I want to conceal as many pipes as possible and need to make allowances for the pipework to be concealed in the floor. I know a lot of plumbers don't like waste pipes concealed beneath floor levels but, like cables, I don't like to see them at all.

Anyway back to my drawing and just in case it's confusing, the top half is a plan view and the bottom half is a side elevation. Anyone got any suggestions/advice. (clean ones only please😛)?

One thing I've spotted is that there is no trap for the dishwasher. As the D/W connects to the waste system through a non vented connection, i.e. no stand pipe, does the system need a trap?

Kind regards.

helpsy · Oct 4, 2010

Hi duffsparky
Welcome.
Wouldn't you be best off running the waste in 50mm(if room) and branching off with the 32mm/40mm runs( i know you using AAV's).
The max length on their own for runs as standard:- reccomended clip spacings:- horizontal:- vertical:-
32mm 1.7 metres 18/20mm fall per metre 0.8 metres 1.5-1.7
40mm 3.0 metres 19/90mm " " 0.9 1.8
50mm 4.0 metres 18/90mm " " 1.0 2.1

duffsparky · Oct 4, 2010

Hi helpsy,

Thanks for the reply.

I've amended the design to show 50mm pipe for the section below the floor level and up to the 40mm branch to the kitchen and added a 50mm access port just before the 32mm branch to the toilet hand basin.

I've also added a hepVO trap for the dishwasher. Modding the pipes for the kitchen sink will not be easy so I'd sooner leave them alone if possible. I can increase the fall to at least 1.5 degs maybe even 2 degs but 2.5 in unlikely, I'll try though.

I've not got much in the way of 50mm waste pipe and what I do have was bought for bathroom mods. I do, however, have plenty/sufficient 110mm pipe plus fittings, would this be better for the pipe laid below the floor?

What are your thoughts?

Cheers.