On Jun 28, 9:01*pm, "Phil L" wrote:
Simon wrote:
On 28 June, 20:40, "Phil L" wrote:
sm_jamieson wrote:
Just had a moment of drama. The main roof gutters of me and
neighbour had a shared downpipe that I guess was supposed to split
equally between the 2 properties. I had temporarily routed both
roofs onto neighbours side whilst extension work is in progress (a
bit naughty I guess). Anyway, just had downpour, and she phones
saying it overflowed and flooded her back door.
Now, we have combined sewer and drains here (1930s house).
I have temporarily re-jigged it so that all water goes to our side,
and down our soil pipe, which currently only extends 2 feet above
first floor, awaiting the extension roof. This will certainly keep
her happy.
But it got me wondering. For a combined sewer, why not just put the
roof drainage into the top of the soil pipe, which passes right by
the gutter ? I mean, a 4 inch pipe from the roof must be the best
solution. Even in heavy rain, there would never be enough water from
the roof to prevent venting when the toilet is flushed.
??
Simon.

Because the top (IE the open end of the soil pipe) has to be a
minimum of one metre higher than the highest opening window, and in
your scenario, it would be gutter height.
This is why soil pipes have the swan neck to take them past the
eaves and gutter and upwards for a stretch before venting.

Well why not have a side inlet boss into the soil pipe ?
Its not so different from an entire large bathtub emptying into the
soil pipe through an
identical inlet at full force a few metres below.
Simon.

Except that a bath or basin has a trap to prevent sewer smells getting into
the room - doing it the way you describe would still vent sewer gas at the
gutter height, IE about a foot, or even less, above an opening light.

--
Phil L
RSRL Tipster Of The Year 2008- Hide quoted text -

- Show quoted text -

Rainwater into the sewage system isn't great from the point of view of
the water company. Older properties would discharge rainwater to the
sewers, but post 1950's built houses should drain gutters to a
soakaway. If you had any sort of extension build, then BC would insist
on soakaways.

Why don't you divert the rain into a large tank and use it for
flushing loo/watering.
As a plus point if you are on water meter then you won't pay to flush/
dispose of your Richard III's.

Dave.