Proposing extension - what about inspection covers?

[daddyfreddy]

Hi Folks,

Okay, looking to make an extension (up to permitted amount) but the ground just behind the house also has a drain inspection cover. What is the situation here regards access to it? Cheers!

[Roger Mills]

It depends on a lot of things! It is an inspection *chamber* that you could climb down into, or just a small rodding eye?

Is it a foul sewer, or just for storm water? How deep is it? What size pipe is at the bottom? Is it a public sewer, or is it a private one - for which you are responsible? In which Water Company area do you live?

If it's a public sewer, you'll need to get permission from your water company to build over it. If they're anything like Severn Trent, you'll have a hell of a lot of hoops to jump through! I built a detached garage over a public sewer - and ended up with an inspection chamber inside the garage. If it's a foul sewer, you won't really want a chamber inside living space - even with a sealed lid. Imagine what will happen if it blocks, and they have to take the lid off - and it then overflows! It would be best to try to divert the whole thing to be *outside* of your extension.

In my case, ST insisted on a before and after CCTV survey - at my expense - to prove that the building operation hadn't damaged the sewer, and insisted that the foundations were taken down to invert level (2.2 metres in places) and bridged over the sewer so as not to place any load on the pipe.

Have fun!

[sm_jamieson]

It could be just an access chamber for your own soil drainage. My extension has a double-seal access chamber in the kitchen floor (will usually be hidden by breakfast bar or somesuch), into which the upstairs and downstairs toilets merge. If the sewage system was backing up, I'd prefer to have to open that chamber than wait for the downstairs toilet to overflow ! At least with the chamber you stand more of a chance of clearing the blockage, with access from both ends. But I don't think I'd want a public sewer chamber in my kitchen. Its OK for me, but Severn Trent invading my house is another thing ! I was also building *near* to the public sewer, but not over it. I had to ensure the foundations were below a line 1 metre away and then 45 degrees upwards from the invert. Simon.

[Invisible Man]

I had an inspection cover in my garage at one house I owned. The sewer served my house and 2 or three others before flowing via other properties to the public main. When I was on holiday there was a blockage upstream that was cleared but evidently reblocked downstream from my locked garage. Result, a very smelly garage. I imagine you would need permission to vary the drainage system or access to it. Depending on what it serves might be worth contemplating moving the run.

[sm_jamieson]

In extreme cases you can re-route the public sewer (under the watchful eyes of the water authority), but is v. expensive and you can't expect other people to stop using their toilets ! I had a scarey sheet from Severn Trent telling me about all of this. Simon.

[Ian_m]

Friends had a extention done and builders had to move both a foul water and storm water drain that would have had inspection covers in their new kitchen if left. I think both drains were "theirs" rather than public so moving inspection covers meant lots of trenches, patio and path dug up, more pipe and inspection covers appearing in their patio.

Neighbour in my last house built a glass lean to type conservatory thing (!!) across his patio (had brick dwarf walls + double glazed so not really a green house) and just lino'ed across the sewer cover. Found out to his cost that cast iron sewer covers lift up when sewers block due to someone lobbing a large nappy down the drain. Sewerage got into his house as well as once conservatory was full started flowing in through the connecting door. My drain cover lifted as well but luckily for me just flowed into neighbours garden mingling with all the liquid coming out of his conservatory doors. Nice.....

[sm_jamieson]

Yeh, inside should always be double-seal and screwed down ! Simon.

[The Natural Philosopher]

Exactamundo.

You CAN leave drains inside under stuff, but as above, it has its drawbacks.

accept that some extensions need extensive groundwork, and leave it at at that. I dont thinbk new drains are the most expensive part of an extension: you generally have a digger in anyway to do the foundations..

First step is to trace whats going on, second is to plan where the new should go..taking the opportunity to extend in case you ever want a bog or bathroom somewhere else, then gird thy loins, grease the digger, and get pipe laying.

I rather enjoy that...

[daddyfreddy]

I'll open it up and see what water is going in it. It's one of these covers with concrete layed into it so don't know how easy it will be to lift.

If it's like the front drain cover it will be shared with neighbours and since the property is relatively new I assume I'm responsible for it, not the water board.

I'm quite happy to keep it in the same place I was more concerned about the council planning guy seeing it and refusing the extension or requiring me to bend over backwards over it.

Cheers all for the input.

[Hugo Nebula]

Which bit; laying the pipe or greasing the digger?

[The Natural Philosopher]

groundwork in general ;-)

As long as you have machines to help, anyway.