Underground Drainage

[milbo1990]

Apologies if I should be posting this in the 'Plumbing' section....

My girlfriend and I will soon be completing the purchase of our first house, which we'll be doing a lot of work to. Fortunately, it has new double glazing, GFCH system and has recently been rewired - however, almost everything else needs addressing!

The first job to do will be to move all of the drainage. This is because we plan to do a single storey extension in the very near future (which will involve moving the SVP) and we want to re-do the bathroom first, hence get the SVP moved before we do the bathroom.

The property is a 1930's semi, with combined drainage at the back of the house, beneath a concrete patio. Plan is to break out the concrete and dig down to all of the drainage so that I can see where it's all going and then re-route it leaving room for the extension and moving the soil stack around to the side of the house, basically making as few changes to the existing system as possible.

We will be putting in a new downstairs toilet in the existing under-stairs cupboard which will also need connecting to the SVP (which will be just through the wall). I also know roughly where the other outlets will be (first floor shower and basin, ground floor wc basin, ground floor kitchen sink and appliances) which currently discharge through the wall into a downpipe which feeds surface water drain. So, should I just get the gulleys in place at this time too and then backfill the whole area?

I understand the principles of drainage, but I've not done any work on it before, so any bits of advice/lessons learned from your more experienced guys would be greatly appreciated!

Thanks in advance.

 

[freddiemercurystwin]

Is there any drainage within 3m of your proposed extension that serves any other properties other than your own?

 

[ivixor]

I'm doing the same thing more or less.

Dig out the concrete - you will want to hire a breaker for that.

Do some trial excavations to see where the pipes run.

Work out if any shared drains are in the way. If not, then it should be relatively straightforward, providing you don't mind being without drainage while you make the connections.

Oh, and you will need to apply for building regs inspection before you do anything.

 

[milbo1990]

Is there any drainage within 3m of your proposed extension that serves any other properties other than your own?

It's difficult to know until I excavate all of the drainage and see where it's going, as it won't be mapped anywhere.

At a guess, because it's a semi; it'll be connected to next-doors drainage (within 3m) somehow and then run out to the sewer in the road, but I'm not sure where the lateral drain/private drain/public sewar will lie until I dig it all out.

Unless you're aware of a way I can work it out?

 

[harry0harry]

Sounds like a big project,best get in a professional to lay the drains and get them approved/signed off by your local council.

Good luck.

 

[mfarrow]

Having the 'joy' of recently finding a 6" pipe I wished to connect to buried in concrete, I can sympathise with your case. Not only that, but it was under another 4" pipe which I wasn't expecting to be there, and was too encased in concrete.

I used a breaker down for the path only, then SDS chisel for the rest. Take your time and there'll be no problem or broken pipe.

To cut the pipe, take your time and buy a pack of stone cutting discs and a 4 1/2" grinder. Cut the top off first. Keep the grinder moving over the workpiece and you shouldn't need more than 2 discs (they overheat and wear quickly if you don't).

Good luck. buy plenty of pea shingle and lots of buckets or a skip.