water drainage

[dombanks]

so ive always been convinced a drain i have doesnt drain. what sort of slope should there be? ive read 1/8" per foot.

the next question is what do you do if you cant get enough slope on a  drain pipe?  is there a way you can zigzag them over a main drain?

i want to sort this drain out before i have a new patio laid over it

[Geoffrey Carter (Buttercup)]

What size drain is it.

Generally a 110mm drain is laid at 1:80. 12.5mm per meter.

What is the drain taking.

Top water or foul.

[dombanks]

grey water. washing machine and i think a the roof water

[Geoffrey Carter (Buttercup)]

I wouldn't want to take anything less than 1:80 for a 110mm diameter pipe but you can go to 1:150 for a 160 mm pipe.

It depends on what size pipes you have to what minimum fall you can go.

Can you lift a chamber lid to see.

in fairness though coming from your house it will generally be 100 / 110mm until it drops into a chamber further downstream.

With regard the "zig zag", you really want your drains to be straight.

Can your local building control advise as they will be on the job to see what you have.

[dombanks]

cool thanks, i just wanted to have an idea before i get someone in. i don't like going in blind (oooeeerr) with stuff like this and there are too many unscrupulous people about. like the plumber who wanted a "consulting fee" and half a days work to connect 2 radiator pipes.

[Kevin Wood]

On 16/03/2019 at 16:23, dombanks said:

grey water. washing machine and i think a the roof water

Might be worth checking that it is connected to the foul sewer rather than a soakaway. It could be that it was originally just a rainwater drain to a soakaway and the washing machine plumbing was added later. Maybe the addition of a regular dousing from the washing machine is overcoming the soakaway.

[dombanks]

Good call... Deffo connected to the main drains .... You can hear the loo flushing