Summer House Extension

[mfarrow]

View media item 20541 View media item 20542 View media item 20543Hi

As you may have seen in the electric's forum, I'm trying to rally opinion on a project I'm managing for my girlfriend's dad, who wants to extend his summer house by adding a W/C.

I've been thinking about the plumbing and although it doesn't have to comply with building regs, I'd like to keep it to the letter as much as possible.

The water will come in via flexi. pipe from a standpipe already in situ, and plumb into the toilet/basin. A 6kW in-line water heater will feed the sink hot water supply.

The waste water will be connected to a redudant connection of the main sewer (see diagram).

Questions:

1. Do I need to inform the water company of my intention to connect (house is 1970, sewer comes from house+neighbour)?
   Are the gradients OK?
   Is 300mm for the waste pipe deep enough? It will lay on a bed of sand but I haven't thought of providing any additional mechanical protection.
   What's so special about a 'rest bend' and do I need one?
   How do people rate those in-line water heaters? Will 6kW be sufficient?

Sorry for all the questions! Thanks!

 

[Nige F]

Nice drawing - shame about the pipe layout !

I think someone here will say it does have to go by Build regs.

Let`s wait a while and see

 

[Richard C]

Oh all right then ; the drainage has to comply with Buiding Regs. & there is no way that does. The Electrics your also doing on your other, identical post must also comply.

Forgot to post the link;
http://www.planningportal.gov.uk/en...kcommonoutbuildings/workmorebregsoutbuilding/

 

[mfarrow]

the drainage has to comply with Buiding Regs.

Isn't this an excempt, Class VI building?

there is no way that does.

Enlighten me please?

Electrics your also doing on your other, identical post must also comply.

Yes I realise that.

 

[Richard C]

Isn't this an excempt, Class VI building?

The building may well be but your connecting to an existing foul drain &, as I understand it, that must comply; as will electrics & safety glass where required. I would strongly advise you check with LABC & would be interested to hear what they say.

there is no way that does.

Enlighten me please?

As you are already aware, you need a rest bend, you must have access to clear blockages either from one end or the other instead & the way you’ve run it & connected with the tee joint as far as I can make out doesn’t provide any; I would connect straight into the existing inspection hatch. If I’m right about it needing to comply, the excavations & backfill must comply with Part H; sand doesn’t. LABC will want to inspect the new connection before you back fill.

Electrics your also doing on your other, identical post must also comply.

Yes I realise that.

Fine; just trying to help.

 

[mfarrow]

The building may well be but your connecting to an existing foul drain &, as I understand it, that must comply; as will electrics & safety glass where required. I would strongly advise you check with LABC & would be interested to hear what they say.

I certainly will do, and I am trying to comply anyway for completions sake.

As you are already aware, you need a rest bend

Ah yes, 1.26, just found it

you must have access to clear blockages either from one end or the other instead & the way you’ve run it & connected with the tee joint as far as I can make out doesn’t provide any; I would connect straight into the existing inspection hatch.

Richard, I've uploaded a pic of the inside of the inspection chamber and what I've come up with for inspection/rodding of the new pipe. I've added a hopper for the gutter water, but obviously I'll need to check that we have combined drainage (or are at least paying for it). Do you think this would cover the requirements?

I don't think the spare way I'm thinking of using is actually in use. There is a length of clay pipe going to it, but how long that is I don't know; as far as I'm aware it's just full of mud.

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If I’m right about it needing to comply, the excavations & backfill must comply with Part H; sand doesn’t.

Sorry I was remembering the guide wrong . Some lovely gravel it is then.

LABC will want to inspect the new connection before you back fill.

Do you think they'll want it pressure testing? Just not really sure how I'd do that

 

[DeltaT]

Blimey, you'd never get away with a manhole on a sewer like that in Scotland!!! Or indeed a branch like that in it, all 'Y' branches required.
Interesting, thanks for sharing.

Up here it would be a new manhole & connection in the manhole only.

 

[mfarrow]

Up here it would be a new manhole & connection in the manhole only.

So is that what I need? I'm trying to think of a practicable solution without digging up the main sewer.

 

[dextrous]

Do you think they'll want it pressure testing? Just not really sure how I'd do that

When it's all in place, bung one end of it (inspection chamber end), and put a u-bend on the other. Fill with water to the rim and leave it there to see how much the level drops.

 

[Nige F]

Is it actually going to be inspected by an official. Hypotheticaly , I would just connect the WC up @ the back of the Summerhouse, in the easiest way and when the place is sold- Pull it out and make the little room a garden tool store . But the I`m just an old- skool Plumber.And I hate Officials.

 

[Richard C]

Richard, I've uploaded a pic of the inside of the inspection chamber and what I've come up with for inspection/rodding of the new pipe. I've added a hopper for the gutter water, but obviously I'll need to check that we have combined drainage (or are at least paying for it). Do you think this would cover the requirements?

Blimey that’s ancient, hope they will agree you to connecting to that, they may want you to replace with a modern chamber. Re the rain hopper; water authorities no longer allow the discharge of surface water into the foul drain system without permission & then only when there is no other alternative; it breaches bi-law so if you get caught you could face a hefty fine. Rather than a shallow inspection chamber you could fit a ramped rodding point by fitting a 45 degree branch at the very top where it dives down to the lower drain invert.

If I’m right about it needing to comply, the excavations & backfill must comply with Part H; sand doesn’t.

Sorry I was remembering the guide wrong . Some lovely gravel it is then.

Use pea gravel 5-10mm max.

Do you think they'll want it pressure testing? Just not really sure how I'd do that

I’ve not been asked to do one yet, always got away with just a visual inspection but it depends on the BI. If they do insist on a test you will probably get away with a water test as Dex states rather than pressure test but you can hire a test kit.

 

[mfarrow]

Thanks for that Richard.

Right, I think I'm all ready to go to the planning authority now.

View media item 20646
What do you reckon? I've reversed that bottom image so it's a reflection of the one above it, just in case its consfuing you.

 

[Richard C]

Very usefull Hunter guides here; download the Complete Brochure PDF here;
http://www.hunterplastics.co.uk/content/1/95/underground-support.html
have a look at page 74, also lots of other info in there to help you.

 

[mfarrow]

Ah, so a ramped access point isn't itself ramped?! (penny's slowly falling now you see).

Do you think I need a rodding point on the stack, or will this be OK?

View media item 20707

 

[Richard C]

As the drain invert is less than 1.3 from the base of the toilet, regulations don’t actually require a vented stack if the drain is vented from another point, which one assumes it must be - it’s in that guide somewhere. But if you don’t vent, you may have problems with siphoning of that washbasin trap unless you fit an anti-siphon trap. If you’ve no windows/door openings at the back then you can get away with a stub stack which will allow access through the top, otherwise the top of the stack must terminate 900mm above any opening within 3 meters.

You show a “Y” connector for the new 45 degree connection into the existing inspection hatch, what’s the purpose of the other drain leg which seems to terminate under the edge of the washbasin? Keep pipe runs as straight as possible; you are allowed one change in direction up to 45 degree, go greater than that or introduce another bend & you will need rodding access from the other end. I’m not sure why you’ve introduced that 45 degree bend at the bottom of the rest bend but I would loose it if possible.

Avoid what I often term “draughtsman’s disease”; a tendency to draw things to a uniform grid pattern, usually at 90 degrees to each other! You can’t see underground pipes; they don’t have to look pretty & can run in any direction you choose!