Downspout to drain pipe, how?

[anta]

We are replacing an underground drain pipe which takes water from our downspouts (round plastic) to a ditch at the other side of the garden. The old one had a large 90 degree bend pointing upwards, and the smaller downspout dropping into it, but this fills with leaves and soil. Can anyone point me in the direction of what components I need please? Some kind of sealed joint with a soil trap would be good, or a grid slightly above ground level. The old underground pipe is cast iron but we're replacing that with a plastic one. Screwfix links or similar so I can see what we're talking about would be fab.

Thanks
Ant

 

[noseall]

i always discharge r.w.p's into trapped gulleys, the compact bottle gulleys are ideal.

this way, all the rubbish is collected in the gulley bottom. it does need cleaning out intermittantly though.

 

[marshman]

http://www.screwfix.com/prods/19993/Plumbing/Underground-Drainage/Universal-Gully-Trap

and its top
http://www.screwfix.com/prods/13687/Plumbing/Underground-Drainage/Square-Hopper-And-Gully-Grid

 

[^woody^]

Rainwater only drains don't need a trap, and if this drain just goes to a ditch, then just a bend will be OK.

To stop leaves etc getting in the drain, just use a vertical section of underground pipe, but fit a proper downpipe to drain connector like this one http://www.screwfix.com/prods/38593/Plumbing/Underground-Drainage/Universal-Rainwater-Adaptor# (lazy me)

Few leaves will then get in and any that do should not collect in the drain if the fall is correct.

I would not use an open top gully unless it was needed for surface drainage or pouring stuff down

 

[noseall]

Rainwater only drains don't need a trap,

my experience of digging out silted up rainwater drain runs, says they do.
there is not a person on this planet who could convince me otherwise.

a rainwater drain will be subject to silt. in the summer, that drain will be dry for periods of time. the laid down silt will crust. there will be a build up.

i have sen 10 year old drains completely blocked.

 

[marshman]

If there is no inspection Chamber in the pipe run and you don't intent to fit a Roding point then this
http://www.screwfix.com/prods/28956/Plumbing/Underground-Drainage/Bottle-Gully-Circular-Grid
is your best option, this will allow Roding of the pipe run and let you clean out all the muck, moss that gets washed down off the roof,
are you changing the old cast pipe because its block solid ?.
Like noseall, we've dug up and replaced many old storm drains that's silted up, its much easier and cheaper to put on rubber gloves and
clean out a gully.

 

[^woody^]

The main purpose of a trap is to stop smells. So if the drain is not on a foul system then there is no need for one in this context.

The amount of debris and grains off a roof, going directly into a a drain is very small but over long time periods. This debris would normally just wash down the drain run with the rain and be no problem, but if a trap is fitted, it will naturally collect there and will consequently require cleaning out - giving the impression that its a lot of debris, when in fact its just very small amounts collected over a very long period of time.

If the drain is in fact a gully, then it may be subject to more debris entering it. Normally there would still be no need for a trap, but if excessive soil, leaves or other crap is expected, then a trap may help cleaning out - but its still most likely that the debris will still just wash down the drain.

If there are silted up drain runs, then that is due to other problems - and the fact that they are silted up anyway defeats the fitting of a trap - it has not helped and prevented silted drains has it!

Thats why I would save the cost and time of fitting a trap which would be unnecessary.

In the OP context, relay the pipe to a proper fall to the trench, fit a bend or rest bend, downpipe into the drain with a sealed connector, and there will be no problem.

 

[noseall]

a gulley will also intercept rubbish, thats what road gulleys do.

i will never fit a r.w.s without some form of interceptor.

 

[^woody^]

Yes, but a highway gully will get lots of debris and chemicals/oil/fuel down them and the gully is designed to prevent as much of this as possible from getting into the rest of the system. You won't get this off your roof!

Come on, I'm trying to save you a few quid here

 

[noseall]

i'm of the mindset woody: 'tis better to have it and not need it, than to need it and not have it.

 

[noseall]

p.s, there is an awful lot of crud leaving the roof via the storm drain. especially over a number of years.

 

[anta]

Thanks for all the replies folks. It is only roof drain water which goes down it, but we live next to a wood so there's lots of leaves collect up there and get washed down, and lots of moss too. The old pipe seems to be about 6 inches short of where it needs to be, and the other end of it cannot be found but is somewhere beneath the root of a hugh lorral tree. We've chopped the tree down but the root remains and we don't fancy digging it out to unearth the outlet end of the pipe which is already too short at the house end, so we're just going to put in a new pipe and fit it properly.

Thanks for all the help.
Ant