Scenario: Double garage built 20yrs ago at the bottom of a garden, with
proper planning permission. But instead of digging a soakaway as on the
plans, just sent the rainwater from the roof into a butt. Which when it
overflows trickles away on the surface to roughly where the soakaway
should have been.

Time has come to put this right, and dig the "missing" soakaway. But
without access to the full original plans, how big (circumference,
depth, capacity) should it be?
--
Roland Perry

Roland Perry wrote:

> Time has come to put this right, and dig the "missing" soakaway. But
> without access to the full original plans, how big (circumference,
> depth, capacity) should it be?

Part H tells you how to do a percolation test, from that you can
calculate the volume, I don't know what duration of storm you should
assume. Are you thinking of using crates?

<https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdf>

On 16/08/2023 09:15, Andy Burns wrote:
> Roland Perry wrote:
>
>> Time has come to put this right, and dig the "missing" soakaway. But
>> without access to the full original plans, how big (circumference,
>> depth, capacity) should it be?
>
> Part H tells you how to do a percolation test, from that you can
> calculate the volume, I don't know what duration of storm you should
> assume.  Are you thinking of using crates?
>
> <https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdf>

Example install of crates
https://youtu.be/He4uUIKAhcE?t=18

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 16/08/2023 08:48, Roland Perry wrote:
> Scenario: Double garage built 20yrs ago at the bottom of a garden, with
> proper planning permission. But instead of digging a soakaway as on the
> plans, just sent the rainwater from the roof into a butt. Which when it
> overflows trickles away on the surface to roughly where the soakaway
> should have been.
>
> Time has come to put this right, and dig the "missing" soakaway. But
> without access to the full original plans, how big (circumference,
> depth, capacity) should it be?

Have you checked with your council's Planning Department to see if they
have a copy of the plans? I was able to view some old plans (on
microfiche IIRC) at the council. For some reason they wouldn't let me
print them, but did allow me to photograph them on the fiche reader screen.

--

Jeff

Many moons ago, before soakaways were a thing, I got my gutters etc,
replaced by plastic ones. I also had another downpipe fitted near my front
door as being in a terrace I found I was getting too much water from the
neighbours which tumbled onto my head when going out of the front door. The
downpip was left to soak away into the lawn. Now at some time a bush was
planted at the place just to the right of the end of the drainpipe. It has
now almost grown up to the upstairs window and needs to be pruned, its I
think been flowering non stop for years. When should one prune it and would
it be of any use making a makeshift soak away by extending the downpipe to
another location and hoping the bush will still be OK as the whole of the
front of the house gets a little pool when it rains hard now of course. I
think its camellia or clematis, there is also a rose there as well.
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Andy Burns" <usenet@andyburns.uk> wrote in message
news:kk3etrFrsp7U1@mid.individual.net...
> Roland Perry wrote:
>
>> Time has come to put this right, and dig the "missing" soakaway. But
>> without access to the full original plans, how big (circumference, depth,
>> capacity) should it be?
>
> Part H tells you how to do a percolation test, from that you can calculate
> the volume, I don't know what duration of storm you should assume. Are
> you thinking of using crates?
>
> <https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdf>

On 16/08/2023 09:52, Jeff Layman wrote:
> On 16/08/2023 08:48, Roland Perry wrote:
>> Scenario: Double garage built 20yrs ago at the bottom of a garden, with
>> proper planning permission. But instead of digging a soakaway as on the
>> plans, just sent the rainwater from the roof into a butt. Which when it
>> overflows trickles away on the surface to roughly where the soakaway
>> should have been.
>>
>> Time has come to put this right, and dig the "missing" soakaway. But
>> without access to the full original plans, how big (circumference,
>> depth, capacity) should it be?
>
> Have you checked with your council's Planning Department to see if they
> have a copy of the plans? I was able to view some old plans (on
> microfiche IIRC) at the council. For some reason they wouldn't let me
> print them, but did allow me to photograph them on the fiche reader screen.

It is even just possible that the plans have been placed on the
council's planning website and might be viewable from there. Our council
certainly does that, but I don't know how far back they stretch (for
example, there are only scans of the approvals for 1978, 79 and 80
changes, but the full plans for 2010 changes at my house).

In message <ubi2ok$383av$1@dont-email.me>, at 09:52:36 on Wed, 16 Aug
2023, Jeff Layman <Jeff@invalid.invalid> remarked:
>On 16/08/2023 08:48, Roland Perry wrote:
>> Scenario: Double garage built 20yrs ago at the bottom of a garden, with
>> proper planning permission. But instead of digging a soakaway as on the
>> plans, just sent the rainwater from the roof into a butt. Which when it
>> overflows trickles away on the surface to roughly where the soakaway
>> should have been.
>> Time has come to put this right, and dig the "missing" soakaway. But
>> without access to the full original plans, how big (circumference,
>> depth, capacity) should it be?
>
>Have you checked with your council's Planning Department to see if they
>have a copy of the plans?

Yes, that's how I have plans in my possession. But it's just an outline
of the garage, and a dotted line saying "soakway is over there".

>I was able to view some old plans (on microfiche IIRC) at the council.
>For some reason they wouldn't let me print them, but did allow me to
>photograph them on the fiche reader screen.

They sent me a pdf.
--
Roland Perry

On 16/08/2023 12:03, Roland Perry wrote:
> Yes, that's how I have plans in my possession. But it's just an outline
> of the garage, and a dotted line saying "soakway is over there".

In general a building inspector would probably tell you what would be
acceptable if it was a new build. There is a formula that looks at roof
area and soil type. And the BI will know what the soil type is.

--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

In message <kk3etrFrsp7U1@mid.individual.net>, at 09:15:56 on Wed, 16
Aug 2023, Andy Burns <usenet@andyburns.uk> remarked:

>> Time has come to put this right, and dig the "missing" soakaway. But
>>without access to the full original plans, how big (circumference,
>>depth, capacity) should it be?
>
>Part H tells you how to do a percolation test, from that you can
>calculate the volume, I don't know what duration of storm you should
>assume. Are you thinking of using crates?

Percolation test seems a bit of a faff. Especially as the overflow from
the butt soaks in almost immediately.

Was expecting to have someone dig a hole [the one in that video is about
what I expected] and fill it with rubble. If it fills up too much in a
storm, the worst that can happen is it overflows onto the surface of the
next few square metres of the garden slightly downhill from my proposed
soakaway site.
--
Roland Perry

In message <5mGwsc3hAL3kFAXZ@perry.uk>, Roland Perry
<roland@perry.co.uk> writes
>In message <kk3etrFrsp7U1@mid.individual.net>, at 09:15:56 on Wed, 16
>Aug 2023, Andy Burns <usenet@andyburns.uk> remarked:
>
>>> Time has come to put this right, and dig the "missing" soakaway. But
>>>without access to the full original plans, how big (circumference,
>>>depth, capacity) should it be?
>>
>>Part H tells you how to do a percolation test, from that you can
>>calculate the volume, I don't know what duration of storm you should
>>assume. Are you thinking of using crates?
>
>Percolation test seems a bit of a faff. Especially as the overflow from
>the butt soaks in almost immediately.
>
>Was expecting to have someone dig a hole [the one in that video is
>about what I expected] and fill it with rubble. If it fills up too much
>in a storm, the worst that can happen is it overflows onto the surface
>of the next few square metres of the garden slightly downhill from my
>proposed soakaway site.

The video showed a very *expensive* soak. Perhaps the owners were seen
to be wealthy.
No mention of any original soak so perhaps the builder relied on the
sand subsoil.
My Aunts house, in Cambridgeshire, had a section of wall subsiding. The
cause turned out to be a damaged drain pipe serving a second floor
bathroom. The builder had miss read the plans and put a 90deg. bend in
salt glaze pipe which my grandfather had damaged by vigorous rodding!

--
Tim Lamb

On 16/08/2023 08:48, Roland Perry wrote:
> Scenario: Double garage built 20yrs ago at the bottom of a garden, with
> proper planning permission. But instead of digging a soakaway as on the
> plans, just sent the rainwater from the roof into a butt. Which when it
> overflows trickles away on the surface to roughly where the soakaway
> should have been.
>
> Time has come to put this right, and dig the "missing" soakaway. But
> without access to the full original plans, how big (circumference,
> depth, capacity) should it be?

It isn't particularly critical, especially since it will gradually fill
up with soil, sand, silt and stuff. The one that wasn't dug 20 yrs ago
would be much smaller now.

You could do a simple calculation of how much water you might expect in
24hrs in exceptional circumstance, you know, mm of rain x length x
breadth of roof.

TW

TimW <timw@nomailta.co.uk> wrote:
> You could do a simple calculation of how much water you might expect in
> 24hrs in exceptional circumstance, you know, mm of rain x length x
> breadth of roof.

Building regs appendix H3 has some maps showing rainfall intensities to design
for, in litres per second per m2:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/442889/BR_PDF_AD_H_2015.pdf

In particular it's peak intensity we're concerned about - it needs to be
sized to accept the peak flow, not the average flow.

Theo

On 16 Aug 2023 at 14:52:45 BST, TimW wrote:

> On 16/08/2023 08:48, Roland Perry wrote:
>> Scenario: Double garage built 20yrs ago at the bottom of a garden, with
>> proper planning permission. But instead of digging a soakaway as on the
>> plans, just sent the rainwater from the roof into a butt. Which when it
>> overflows trickles away on the surface to roughly where the soakaway
>> should have been.
>>
>> Time has come to put this right, and dig the "missing" soakaway. But
>> without access to the full original plans, how big (circumference,
>> depth, capacity) should it be?
>
>
> It isn't particularly critical, especially since it will gradually fill
> up with soil, sand, silt and stuff. The one that wasn't dug 20 yrs ago
> would be much smaller now.
>
> You could do a simple calculation of how much water you might expect in
> 24hrs in exceptional circumstance, you know, mm of rain x length x
> breadth of roof.
>

Indeed - I was getting 50l/hr measured off a small lean-to in some of the
heavier recent rain.

And uphill next door's gutter was blocked, directing all the rain from the
side of a large detached house and 20m extension into my 1.5m high 10m long
stone wall, causing it to shift and lean a few more inches and wedge the side
gate closed. Well, that's my uneducated guess, but there must have been tons
of water over the recent rainy spell backing up.

--
Cheers, Rob, Sheffield UK

In message <QyBL$hG7rL3kFwDI@marfordfarm.demon.co.uk>, at 13:03:07 on
Wed, 16 Aug 2023, Tim Lamb <tim@marfordfarm.demon.co.uk> remarked:
>In message <5mGwsc3hAL3kFAXZ@perry.uk>, Roland Perry
><roland@perry.co.uk> writes
>>In message <kk3etrFrsp7U1@mid.individual.net>, at 09:15:56 on Wed, 16
>>Aug 2023, Andy Burns <usenet@andyburns.uk> remarked:
>>
>>>> Time has come to put this right, and dig the "missing" soakaway.
>>>>But without access to the full original plans, how big
>>>>(circumference, depth, capacity) should it be?
>>>
>>>Part H tells you how to do a percolation test, from that you can
>>>calculate the volume, I don't know what duration of storm you should
>>>assume. Are you thinking of using crates?
>>
>>Percolation test seems a bit of a faff. Especially as the overflow
>>from the butt soaks in almost immediately.
>>
>>Was expecting to have someone dig a hole [the one in that video is
>>about what I expected] and fill it with rubble. If it fills up too
>>much in a storm, the worst that can happen is it overflows onto the
>>surface of the next few square metres of the garden slightly downhill
>>from my proposed soakaway site.
>
>The video showed a very *expensive* soak. Perhaps the owners were seen
>to be wealthy.
>No mention of any original soak so perhaps the builder relied on the
>sand subsoil.

Somewhere I have a soil survey which was part of the searches when the
property was bought. I'd expect it to be pretty porous.

Unlike one house I had in the Chilterns which had about six inches of
soil on top of very solid chalk.

--
Roland Perry

On Wed, 16 Aug 2023 12:16:49 +0100, Roland Perry <roland@perry.co.uk> wrote:

>Was expecting to have someone dig a hole [the one in that video is about
>what I expected] and fill it with rubble. If it fills up too much in a
>storm, the worst that can happen is it overflows onto the surface of the
>next few square metres of the garden slightly downhill from my proposed
>soakaway site.

That -- but don't fill it with rubble.

Instead, stick crates in it, or mortar tubs, or a plastic/metal bin, oil drum,
.... with large holes in it, or the bottom cut out, or ...

This makes removing the silt that eventually collects and clogs much easier. And
the open volume means that the soakaway can hold a lot more water, from say a
short hard rain, and then drain it away slowly.

And do make it so wide and deep that cleaning it is possible.

I have a 60 cm x 60 cm by 100 cm deep soakaway, and that is a size ratio that
is "difficult": too small to get a handled tool in and work it well, and too
deep to reach into easily. Ended up having to buy an auger!

Thomas Prufer

On 17/08/2023 06:35, Roland Perry wrote:
> Somewhere I have a soil survey which was part of the searches when the
> property was bought. I'd expect it to be pretty porous.
>
> Unlike one house I had in the Chilterns which had about six inches of
> soil on top of very solid chalk.

And you think that chalk isn't the most porous rock there is?
Sheesh

Quelle môrone

--
All political activity makes complete sense once the proposition that
all government is basically a self-legalising protection racket, is
fully understood.

On 17/08/2023 07:45, Thomas Prufer wrote:
> On Wed, 16 Aug 2023 12:16:49 +0100, Roland Perry <roland@perry.co.uk> wrote:
>
>> Was expecting to have someone dig a hole [the one in that video is about
>> what I expected] and fill it with rubble. If it fills up too much in a
>> storm, the worst that can happen is it overflows onto the surface of the
>> next few square metres of the garden slightly downhill from my proposed
>> soakaway site.
>
> That -- but don't fill it with rubble.
>
> Instead, stick crates in it, or mortar tubs, or a plastic/metal bin, oil drum,
> ... with large holes in it, or the bottom cut out, or ...
>
> This makes removing the silt that eventually collects and clogs much easier. And
> the open volume means that the soakaway can hold a lot more water, from say a
> short hard rain, and then drain it away slowly.
>
> And do make it so wide and deep that cleaning it is possible.
>
> I have a 60 cm x 60 cm by 100 cm deep soakaway, and that is a size ratio that
> is "difficult": too small to get a handled tool in and work it well, and too
> deep to reach into easily. Ended up having to buy an auger!
>
>
> Thomas Prufer

In fact soakaways work well filled with rubble or gravel or crushed
limestone or anything porous provided they have a roof on.

After twenty years, hire a digger.

--
All political activity makes complete sense once the proposition that
all government is basically a self-legalising protection racket, is
fully understood.

On 17/08/2023 08:09, The Natural Philosopher wrote:
> On 17/08/2023 06:35, Roland Perry wrote:
>> Somewhere I have a soil survey which was part of the searches when the
>> property was bought. I'd expect it to be pretty porous.
>>
>> Unlike one house I had in the Chilterns which had about six inches of
>> soil on top of very solid chalk.
>
> And you think that chalk isn't the most porous rock there is?
> Sheesh

But just how porous? And, more to the point, how /permeable/ is it? I've
just been introduced to the wonderful world of the millidarcy. :-)

It seems that chalk has two permeabilities, the secondary of which, due
to its fracture system, is 100 - 1000 times that of its primary
permeability:
<https://www.lyellcollection.org/doi/abs/10.1144/gsl.sp.1987.034.01.10>

There's an amazing amount of stuff on the internet to waste time on!

--

Jeff

In message <ubkh46$3mg8s$3@dont-email.me>, at 08:09:58 on Thu, 17 Aug
2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>On 17/08/2023 06:35, Roland Perry wrote:
>> Somewhere I have a soil survey which was part of the searches when
>>the property was bought. I'd expect it to be pretty porous.
>> Unlike one house I had in the Chilterns which had about six inches
>>of soil on top of very solid chalk.
>
>And you think that chalk isn't the most porous rock there is?
>Sheesh

Because that chalk was tougher than concrete. Builders used to moan
about being forced to excavate it to make statutory foundations, out
of a softer material.
--
Roland Perry

On 18/08/2023 08:09, Roland Perry wrote:
> In message <ubkh46$3mg8s$3@dont-email.me>, at 08:09:58 on Thu, 17 Aug
> 2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>> On 17/08/2023 06:35, Roland Perry wrote:
>>> Somewhere I have a soil survey which was part of the searches when
>>> the  property was bought. I'd expect it to be pretty porous.
>>>  Unlike one house I had in the Chilterns which had about six inches
>>> of  soil on top of very solid chalk.
>>
>> And you think that chalk isn't the most porous rock there is?
>> Sheesh
>
> Because that chalk was tougher than concrete. Builders used to moan
> about being forced to excavate it to make statutory foundations, out
> of a softer material.

Chalk is not tougher than concrete. End of.

--
"Women actually are capable of being far more than the feminists will
let them."

In message <ubkh83$3mg8s$4@dont-email.me>, at 08:12:03 on Thu, 17 Aug
2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>On 17/08/2023 07:45, Thomas Prufer wrote:
>> On Wed, 16 Aug 2023 12:16:49 +0100, Roland Perry <roland@perry.co.uk> wrote:
>>
>>> Was expecting to have someone dig a hole [the one in that video is
>>>about
>>> what I expected] and fill it with rubble. If it fills up too much in a
>>> storm, the worst that can happen is it overflows onto the surface of the
>>> next few square metres of the garden slightly downhill from my proposed
>>> soakaway site.

>> That -- but don't fill it with rubble.
>> Instead, stick crates in it, or mortar tubs, or a plastic/metal bin,
>>oil drum,

>> ... with large holes in it, or the bottom cut out, or ... This
>>makes removing the silt that eventually collects and clogs much
>>easier. And the open volume means that the soakaway can hold a lot
>>more water, from say a short hard rain, and then drain it away
>>slowly. And do make it so wide and deep that cleaning it is
>>possible. I have a 60 cm x 60 cm by 100 cm deep soakaway, and that
>>is a size ratio that is "difficult": too small to get a handled tool
>>in and work it well, and too deep to reach into easily. Ended up
>>having to buy an auger!
>
>In fact soakaways work well filled with rubble or gravel or crushed
>limestone or anything porous provided they have a roof on.
>
>After twenty years, hire a digger.

I'm expecting to hire two diggers: a bloke plus a small backhoe.

Rainfall estimates: this morning's weather forecast says expect up to
6cm on Friday night, garage is 5.8m square, and some of the references
given earlier say x 1.5, which gives 3 cubic metres.

I suppose the water butt is 210 litre = 0.2 cubic metre. Which seems a
bit undersized. And it's always full (apart from anything else the tap
at the bottom is seized up). So it's all just running off at the moment.
--
Roland Perry

On 18/08/2023 08:32, The Natural Philosopher wrote:
> On 18/08/2023 08:09, Roland Perry wrote:
>> In message <ubkh46$3mg8s$3@dont-email.me>, at 08:09:58 on Thu, 17 Aug
>> 2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>>> On 17/08/2023 06:35, Roland Perry wrote:
>>>> Somewhere I have a soil survey which was part of the searches when
>>>> the  property was bought. I'd expect it to be pretty porous.
>>>>  Unlike one house I had in the Chilterns which had about six inches
>>>> of  soil on top of very solid chalk.
>>>
>>> And you think that chalk isn't the most porous rock there is?
>>> Sheesh
>>
>> Because that chalk was tougher than concrete. Builders used to moan
>> about being forced to excavate it to make statutory foundations, out
>> of a softer material.
>
> Chalk is not tougher than concrete. End of.
>

Nor is subsoil. End of.

If the chalk layer is metres thick then there is no advantage
in digging a 750 cm trench compared to a 450cm deep trench.
It supports the same weight.

On 17/08/2023 08:12, The Natural Philosopher wrote:
> On 17/08/2023 07:45, Thomas Prufer wrote:
>> On Wed, 16 Aug 2023 12:16:49 +0100, Roland Perry <roland@perry.co.uk>
>> wrote:
>>
>>> Was expecting to have someone dig a hole [the one in that video is about
>>> what I expected] and fill it with rubble. If it fills up too much in a
>>> storm, the worst that can happen is it overflows onto the surface of the
>>> next few square metres of the garden slightly downhill from my proposed
>>> soakaway site.
>>
>> That -- but don't fill it with rubble.
>>
>> Instead, stick crates in it, or mortar tubs, or a plastic/metal bin,
>> oil drum,
>> ... with large holes in it, or the bottom cut out, or ...
>>
>> This makes removing the silt that eventually collects and clogs much
>> easier. And
>> the open volume means that the soakaway can hold a lot more water,
>> from say a
>> short hard rain, and then drain it away slowly.
>>
>> And do make it so wide and deep that cleaning it is possible.
>>
>> I have a 60 cm x 60 cm by 100 cm  deep soakaway, and that is a size
>> ratio that
>> is "difficult": too small to get a handled tool in and work it well,
>> and too
>> deep to reach into easily. Ended up having to buy an auger!
>>
>>
>> Thomas Prufer
>
> In fact soakaways work well filled with rubble or gravel or crushed
> limestone or anything porous provided they have a roof on.
>
> After twenty years, hire a digger.
>
>
Until you use it to dispose of condensing boiler condensate

In message <ubn6pr$5vqa$2@dont-email.me>, at 08:32:11 on Fri, 18 Aug
2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>On 18/08/2023 08:09, Roland Perry wrote:
>> In message <ubkh46$3mg8s$3@dont-email.me>, at 08:09:58 on Thu, 17 Aug
>>2023, The Natural Philosopher <tnp@invalid.invalid> remarked:
>>> On 17/08/2023 06:35, Roland Perry wrote:
>>>> Somewhere I have a soil survey which was part of the searches when
>>>>the  property was bought. I'd expect it to be pretty porous.
>>>>  Unlike one house I had in the Chilterns which had about six inches
>>>>of  soil on top of very solid chalk.
>>>
>>> And you think that chalk isn't the most porous rock there is?
>>> Sheesh

>> Because that chalk was tougher than concrete. Builders used to moan
>>about being forced to excavate it to make statutory foundations, out
>> of a softer material.
>
>Chalk is not tougher than concrete. End of.

You need to go to that part of the Chilterns some time and see. I don't
now exactly what compound it is, but very slightly rubbery, and
extremely difficult to chip away at. Concrete you can fracture more
easily.
--
Roland Perry