Rules of thumb for guttering and number of downpipes?

Hi,
Warmer weather cometh and it's time to put the guttering back...
I have 4 downpipes.
One is blocked, but only served a 3m bit of flat roof and there's a gulley drain nearby (yes I already pay for rainwater down the drains).
Of the other 3, 2 are at the front of the house and one at one end of the rear - 3 corners basically.
I *thought* these were connected to the sewer, but a test with a hose shows they are not - and more annoyingly, that one is blocked and holed and spewing water below ground (below concrete).
I'm considering switching to just the two diagonally opposed downpipes. Gawd knows where they go, but they seem to run free.
For a hipped roof 11.6 x 8m (bungalow) are two downpipes diagonally opposite likely to cut the mustard? The guttering is 4.5" half round - though a lot had rusted away, and whilst I could use a deep section to replace it, I'd waste a fair amount of good guttering.
It would be unwelcome work at this stage to investigate the blocked drain - though I am tempted to buy a 40 quid 5m-leaded usb camera from ebay to make sure the other 2 drains go a reasonable distance from the foundations.
BTW - what is a resonable distance? I seem to recall 5m being mentioned somewhere as current standards, but should I worry if it was 2m, or 3m?
Cheers!
Tim
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Snippage.
ISTR rainwater provision is based on 3/4" in one hour. Somebody else may know more.
Blocked soaks here are invariably caused by roof and gutter debris collecting at the outlet to the soakaway pit and eventually blocking the pipe. As you say, 5m is the current minimum distance from foundations but BCO may have agreed something different. If you have two drains fed to the same soak and can determine the direction of the pipes then a bit of drawing may fix the place to dig. Rainwater gulleys rarely have rodding access which would otherwise give you a direction and distance .

Tree roots, particularly Leylandi can be a problem but more common on damaged sewers.

Over to Hugo. I would be very worried if the soil was sandy at 2-3m distance.
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Tim Lamb

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On Monday 08 April 2013 09:40 Tim Lamb wrote in uk.d-i-y:

Hi,
Probably not in 1950 :) Or 1970... These soakways are either original or modified when some mods were done to the house.

The one that is blocked seems to be full of debris - I managed to shove a hose down and clear the first blockage, which is when it spewed forth from just below ground - probably a holed pipe (thin steel) combined with blockage.

We're solid clay here - the foundation strip sits on the clay.
It might be prudent to lay some new soakaways in.
One of the apaprantly working soaks goes under the drive, so I'm hoping to not have to touch that. Good candidiate for a camera.
The other two are not too bad - 3ft concrete path in the way, but I want to get rid of that, so chopping a bit out will do no harm.
As we have very heavy clay not far down, I'm wondering if a land drain pipe on the end of a plain pipe (to distance itself from the building) and bury the landdrain in gravel might be the way to go, Dump the water over a 3m length of garden perhaps.
I would put traps in at the downpipe base this time, with clearing access - to catch grit if nothing else.
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Tim, our bungalow is about the same roof size, and like yours originally had a downpipe at each corner. We built an extension on the end, and as part of the roof extension rejigged the gutters. At the front I was persuaded by our (otherwise very good) builder to go for one central(ish) down pipe. It was fine in gentle rain, but in a decent downpour didn't cope, and we had water pouring over the gutter rims - even with the outlet fully clear. I've now gone back to a downpipe at each end, and the problem has gone away, even with some leaves and moss in the outlets..
Charles F
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On Monday 08 April 2013 12:30 Charles Fearnley wrote in uk.d-i-y:

Thanks Charles,
That's useful to know.
I'm now going to try to toss up whether to fix the blocked drain or to use a deep profile gutter.
I really wanted to keep the cast ali gutters. That is available in deep profile, but it's *very* expensive (whereas the half round cast ali gutters are just *expensive*).
I have the BCO coming round anyway to sign off the roof retile, so I will seek guidance re proper soakways.
I guess I could put the gutter back with the current downpipe patten and divert the blocked downpipe to run over the concrete path in the meantime - that has a string slope downhill away from the house and will disperse the flow over a wide strip of earth 1.5m away from the house.
Will be better than injecting it right by the foundations, at least for a couple of months...
*sigh* the work never ends...
Cheers, Tim
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On Sun, 07 Apr 2013 22:03:17 +0100, Tim Watts wrote:

Recognising your wish to retain the look of metal guttering, I still think in the long term you may be better off changing to deep profile plastic guttering.
The number of issues you describe with the blocking of the soakaways, the leaking pipes, the clay subsoil, tracing underground pipes etc. suggest that you may be storing up similar problems in the future.
We have nearly all our roof (3 bed semi and car port and veranda) going into a single downpipe into the sewers and so far it seems to cope.
In the long run it is probably best to just bite the bullet and replace all the guttering. Places like fascias.com can supply at a reasonable cost.
Cheers
Dave R
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On Monday 08 April 2013 13:16 David.WE.Roberts wrote in uk.d-i-y:

Quite possible... Seems I can't finish one job without getting diverted onto another...

Impressive...

You can get deep profile "cast effect" -
http://www.drainageonline.co.uk/
The only thing that annoys me about plastic is leaning ladders against it...
Sadly, re sewers, I have one pit that would be easy to make a connection and is 2m from a downpipe - but it's the "wrong" corner - at the back. Are you allowed to make new sewer connections for rainwater?
So I'm going to have to go with soakaways... As I say, redigging 2 is not too bad given it'll be an 18" deep trench (no point in going lower as it's all clay).
The only one I will have to hope is OK is the one under the drive - that would be a right PITA to dig up, though I could still camera it.
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On Mon, 08 Apr 2013 13:30:18 +0100, Tim Watts wrote:
<snip>

In theory if you make any changes to the soil pipes you need Building Control approval.
However it is quite unlikely that anyone would notice, so you have to decide if you want to be pragmatic.
Our builders were amazed that I took photos of the new drain run to the shed at the bottom of the garden to show to BC - they told me I was telling BC far too much :)
We did it quickly because we had a digger on hire and there was an opportunity to dig, lay, and backfill all in one day.
With regard to the 'wrong corner', I assume that if you renew all the guttering then you can organise the flow whichever way you want.
Our guttering has always flowed from the front of the house to the far corner of the back (don't know why but they all do it), so the longest possible run instead of meeting at a half way point.
I don't know your layout, but I can't help thinking that replacing all the guttering with new, all sloped to one downpipe which goes into a convenient manhole, might be easier that re-engineering several downpipes and variable slopes.
Still, you are the one doing it :)
Best of luck.
Dave R
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On Tuesday 09 April 2013 15:47 David.WE.Roberts wrote in uk.d-i-y:

Thanks for that - useful thoughts...

Yes, indeed :)
It might be sane to send the west side round there where there'll be a centre downpipe which I can drop into a handy gully drain (to the sewer) for now (if not forever).
The south side with the bays will easily run down the east side (straight) run) to the unblocked corner drain - and if I find out that is too near the house, it is also the easiliest to redig.
This shows what I mean (needs fixed font)
ROAD ROAD ROAD ROAD ROAD ROAD ROAD ROAD ROAD ROAD
LOW GROUND
South East West Main Sewer DRIVE DRIVE DRIVE ^ | | <<<< <<<< >>>> | ========= ========= ========= V | V | | | | | | | == ========== ==== === V | V | | | | | | | | | | | V HIGH GROUND | V | | | | | | | | | D1| | | =============================== | V S1---- >>>> G D2<<<| | | \ ---- | ============ | \ / <<<< | ------------S2--------------S3
North
It's a bit weird but it could work and give me 2 sewer connections.
Key: >>> <<<< V show rain flow direction in gutter S1,S2,S3 are sewer manholes and the lines between show the sewer runs. G is an existing gulley drain ton the sewer D1, D2 proposed downpipes.
D1 esists now into a soakway in unknown location. There is a blocked soakway downpipe on the SE corner. There is another working, but unknown location soakaway connection on the SW corner - probably under the drive.
D2 is no problem - into gulley. D1 could be hooked into inspection chamber S1 easily (it's new and has a spare inlet blanked off in the right side).
My gut instinct is that a deep gutter would probably manage to route that flow.
What's the panel think?
HIGH GROUND

Well, if the above works, one will be going into a gully to sewer and the other could be connected to a manhole 1.5m away.

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David.WE.Roberts wrote:

What about the 'mock cast iron' uPVC gutter/downpipe?
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On Monday 08 April 2013 20:21 Andy Burns wrote in uk.d-i-y:

Yes - I'm tempted.
Who's better: Brett Martin[1] or Floplast?
http://www.drainageonline.co.uk/Guttering/Brett-Martin-Guttering.htm
http://www.fascias.co.uk/contents/en-uk/d537_Guttering_Systems.html
There's both a round deep style and a stepped-square style - either would probably look good and the latter has massive flow rates.
[1] I've had a bit of Brett Martin's half round cast effect - not bad from a distance, but a bit of a bitch to clip.
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On 09/04/2013 15:21, Tim Watts wrote:

I'd imagine Brett Martin is better than Flop Last. That doesn't seem a great branding for a gutter :)
Andy
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