Simon wrote:
On 28 June, 21:01, "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.

--
Yeah, I guess you could put a trap in !
Anyway I have trapped gully to drain into on the plans, this is just
interim ;-)
Simon.

Interim is fine, but as you said, the gullies have a trap in them and this
is the reason why

--
Phil L
RSRL Tipster Of The Year 2008