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Garage roof rainwater problem.
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Dan S. MacAbre
Jul 11, 2016, 9:28:35 AM7/11/16
to
My mum and dad's garage flat roof has a gutter at one end that runs via
a drainpipe into a grid that just leads into a soakaway. Needless to
say, said soakaway silted up years ago; and now, whenever it rains
(which it has done rather a lot of recently), their patio floods nicely.
The nearest downpipe from the roof goes between their house and their
neighbour's between two conservatories, and wouldn't be easy to connect
to (especially since the water would be required to flow uphill); but
there is a soil stack about eight feet away. Can it be connected to
that? Or is a water butt the best (and only legal) option?
a drainpipe into a grid that just leads into a soakaway. Needless to
say, said soakaway silted up years ago; and now, whenever it rains
(which it has done rather a lot of recently), their patio floods nicely.
The nearest downpipe from the roof goes between their house and their
neighbour's between two conservatories, and wouldn't be easy to connect
to (especially since the water would be required to flow uphill); but
there is a soil stack about eight feet away. Can it be connected to
that? Or is a water butt the best (and only legal) option?
Phil L
Jul 11, 2016, 4:19:41 PM7/11/16
to
gutter of the garage.
A water butt would probably be the easiest solution. there are others but
they would cost a few quid more than a butt and require a bit of work
Dan S. MacAbre
Jul 12, 2016, 4:16:24 AM7/12/16
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Phil L wrote:
> Dan S. MacAbre wrote:
>> My mum and dad's garage flat roof has a gutter at one end that runs
>> via a drainpipe into a grid that just leads into a soakaway. Needless to
>> say, said soakaway silted up years ago; and now, whenever
>> it rains (which it has done rather a lot of recently), their patio
>> floods nicely. The nearest downpipe from the roof goes between their
>> house and their neighbour's between two conservatories, and wouldn't
>> be easy to connect to (especially since the water would be required
>> to flow uphill); but there is a soil stack about eight feet away. Can it
>> be connected to that? Or is a water butt the best (and only
>> legal) option?
>
> It can't really go into the stack as the sewer smells will end up in the
> gutter of the garage.
>
Good point :-) There are lots of other things going into it, since it
> Dan S. MacAbre wrote:
>> My mum and dad's garage flat roof has a gutter at one end that runs
>> via a drainpipe into a grid that just leads into a soakaway. Needless to
>> say, said soakaway silted up years ago; and now, whenever
>> it rains (which it has done rather a lot of recently), their patio
>> floods nicely. The nearest downpipe from the roof goes between their
>> house and their neighbour's between two conservatories, and wouldn't
>> be easy to connect to (especially since the water would be required
>> to flow uphill); but there is a soil stack about eight feet away. Can it
>> be connected to that? Or is a water butt the best (and only
>> legal) option?
>
> It can't really go into the stack as the sewer smells will end up in the
> gutter of the garage.
>
lines up nicely with the kitchen, but they all have traps.
> A water butt would probably be the easiest solution. there are others but
> they would cost a few quid more than a butt and require a bit of work
>
emptying it daily.
Dan S. MacAbre
Jul 12, 2016, 4:49:53 AM7/12/16
to
Chris Hogg wrote:
> You could bodge it like this: http://tinyurl.com/zqhj4xv but two
I'd sort of imagined something like that, and it's interesting to see it
done. The roof doesn't get much stuff on it - there are no trees
nearby, and no gravel; but I remember that our own gutters were once
blocked by soil (lovely quality, too), and I've no idea where that came
from. Probably rotten moss.
> issues. 1) the trap would soon get blocked by debris off the roof, and
> 2) your local water authority might not take kindly to having
> rainwater discharged into the sewer system. AIUI some WA's are OK with
> that, but others not, as it may overload the sewerage system's
> capacity and raw sewage may get forced up through manholes etc.
>
> The best option is to dig out and redo the soakaway.
It sounds like one hell of a job, but I'll see what I can find out.
I've no idea what I'd find down there. It's at the bottom of a natural
depression anyway, so I've no idea how it was ever expected to work.
I'd sort of imagined something like that, and it's interesting to see it
done. The roof doesn't get much stuff on it - there are no trees
nearby, and no gravel; but I remember that our own gutters were once
blocked by soil (lovely quality, too), and I've no idea where that came
from. Probably rotten moss.
> issues. 1) the trap would soon get blocked by debris off the roof, and
> 2) your local water authority might not take kindly to having
> rainwater discharged into the sewer system. AIUI some WA's are OK with
> that, but others not, as it may overload the sewerage system's
> capacity and raw sewage may get forced up through manholes etc.
>
> The best option is to dig out and redo the soakaway.
It sounds like one hell of a job, but I'll see what I can find out.
I've no idea what I'd find down there. It's at the bottom of a natural
depression anyway, so I've no idea how it was ever expected to work.
tabb...@gmail.com
Jul 12, 2016, 4:51:21 AM7/12/16
to
FWIW water can drain uphill if it has a head of water pushing it. But you don't want that outdoors, it'll freeze and split the pipe.
NT
Dan S. MacAbre
Jul 12, 2016, 5:49:18 AM7/12/16
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Davidm
Jul 12, 2016, 5:53:02 AM7/12/16
to
On Mon, 11 Jul 2016 14:28:32 +0100, "Dan S. MacAbre" <n...@way.com>
wrote:
The whole rear roof on my Victorian house discharges into the main
sewer, via a gully/trap where the kitchen waste water goes. Been like
this since the house was built.
wrote:
sewer, via a gully/trap where the kitchen waste water goes. Been like
this since the house was built.
Robin
Jul 12, 2016, 9:21:05 AM7/12/16
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On 12/07/2016 10:52, Davidm wrote:
> The whole rear roof on my Victorian house discharges into the main
> sewer, via a gully/trap where the kitchen waste water goes. Been like
> this since the house was built.
>
Yes but (a) there is a trap - and one which is relatively easy to clear
> The whole rear roof on my Victorian house discharges into the main
> sewer, via a gully/trap where the kitchen waste water goes. Been like
> this since the house was built.
>
of leaves, moss, dead rats and other dross; and (b) in later times many
houses were built with separate rain water and sewage systems.
--
Robin
reply-to address is (intended to be) valid
Phil L
Jul 12, 2016, 3:02:53 PM7/12/16
to
Dan S. MacAbre wrote:
And don't fall for the 'hole full of rocks' method as these work for about a
month, after which they are simply 'rocks with soil inbetween them' IE,
ground that the rainwater passes over on it's way to somewhere else,
probably your patio.
You can wrap two plastic beer crates in weed membrane (several layers and
well taped), bury these and run the outlet into these underground. If the
gutters get mossy, this method will fill the soakaway with moss in short
time, so maybe better to run the outlet onto the top of them, the top can be
disguised with half bricks or broken paving.
I built a small one a few days ago on a site I'm working on, I used two
plastic manhole rings 450mm by250mm sitting on 75mm stone 100mm deep over
the subsoil, which is actually sand.
The thing ended up 450(W) X 500(H). I ran an underground drain into the top
then cut a paving slab to fit the top, then put 100mm concrete over the lot
> Chris Hogg wrote:
>>
>> The best option is to dig out and redo the soakaway.
>
> It sounds like one hell of a job, but I'll see what I can find out.
> I've no idea what I'd find down there. It's at the bottom of a
> natural depression anyway, so I've no idea how it was ever expected
> to work.
It doesn't need to be huge.
>>
>> The best option is to dig out and redo the soakaway.
>
> It sounds like one hell of a job, but I'll see what I can find out.
> I've no idea what I'd find down there. It's at the bottom of a
> natural depression anyway, so I've no idea how it was ever expected
> to work.
And don't fall for the 'hole full of rocks' method as these work for about a
month, after which they are simply 'rocks with soil inbetween them' IE,
ground that the rainwater passes over on it's way to somewhere else,
probably your patio.
You can wrap two plastic beer crates in weed membrane (several layers and
well taped), bury these and run the outlet into these underground. If the
gutters get mossy, this method will fill the soakaway with moss in short
time, so maybe better to run the outlet onto the top of them, the top can be
disguised with half bricks or broken paving.
I built a small one a few days ago on a site I'm working on, I used two
plastic manhole rings 450mm by250mm sitting on 75mm stone 100mm deep over
the subsoil, which is actually sand.
The thing ended up 450(W) X 500(H). I ran an underground drain into the top
then cut a paving slab to fit the top, then put 100mm concrete over the lot
Dan S. MacAbre
Jul 13, 2016, 4:42:09 AM7/13/16
to
Presumably, it relies on having good (i.e. not clay) soil?
David
Jul 13, 2016, 12:15:08 PM7/13/16
to
gasses leaking out, the answer is "it depends".
If the rain water from your main house already empties into the main sewer
then it is probably O.K. to use the main sewer - but this is at the
discretion of your local water authority.
If your main house drains into a separate storm water drain one or more
soakaways then they are unlikely to permit you to use the main sewer.
However you could always ask.
A water butt seems to me to be only delaying the problem.
Once it has filled up then you will get exactly the same volume of water
off the roof wanting to go to exactly the same place.
Fixing or replacing the soakaway is probably your best bet (but see above).
Oh, and on the subject of traps - normally a waste water trap outside is
sunk into the ground and connected to the drain underground. Sinks and the
like have a U bend trap fitted underneath then a direct connection to the
soil pipe pipe (inside or out).
I am trying to find a reason not to fit a trap half way up the garage wall
so that your gutter drains into it but you can still connect to the soil
stack above the ground. As long as it is in a place where you can service
it easily.
Cheers
Dave R
--
Windows 8.1 on PCSpecialist box
Phil L
Jul 13, 2016, 3:37:16 PM7/13/16
to
Dan S. MacAbre wrote:
>
> Thanks, that sounds interesting, and easy to examine in the future.
> Presumably, it relies on having good (i.e. not clay) soil?
It works best without clay soil yes, sand, chalk, stone etc will drain
>
> Thanks, that sounds interesting, and easy to examine in the future.
> Presumably, it relies on having good (i.e. not clay) soil?
farily quickly, clay tends to hold it.
All you are doing is creating a holding tank which fills during a heavy
downpour and then seeps away later
Peter Andrews
Jul 13, 2016, 6:25:11 PM7/13/16
to
laid down the garden in a suitable location (a soak away without any
digging) you can leave the tap turned on during the wetter months so
that the butt drains out and can normally cope with the next rainfall
without overflowing and then when it's drier you can turn the tap off to
conserve the water for use when you need it.
Peter
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