Toilet soil pipe fall

[walkern]

Hello,
I've done my drains and the building controller is round on Monday, just wanted to check something.

On my run from toilet to waste (downstairs toilet) I have a fall of 150mm over 9m. I've calculated this as being 1:60 gradient, or 17mm fall every metre.

Is this ok? I think I've read that anywhere from 1:40 to 1:110 is ok and 18mm every metre is the starting point (from what I can find online anyway).

Thanks.

 

[noseall]

That's seems like a reasonable amount of fall. We have successfully laid drains with less. He may not like that bend in the run though.

 

[^woody^]

What bend?

 

[walkern]

There's a small bend from the toilet end, in the first picture. I figured this would be ok...

 

[tomfe]

Yeah it will be.
You should not have 90 degree bends but 30/15deg is fine.

It would have been better however to use pea gravel (river bed rounded etc) not angular gavel.
You'll also need to protect those pipes with a hard surface over the top (due to the depth) but I guess you are going to do a path so you'll be alright.

 

[walkern]

Well, I was told this is washed and 'made' especially for this job and better than pea gravel.

It should do at £35 a ton. Five more than my sharp and tenner more than mot 1.

Thanks for the advice, it's appreciated.

 

[tomfe]

It's going going to make any difference now but pea gravel is self compacting/flowing and easier to move where as 1 inch clean can clump. BR says 5-10mm stone. You could have bedded it in sand also.