DIY Doctor

Help Manhole issues!

Postby cshaw » Thu Aug 07, 2008 3:58 pm

Afternoon all

I am currently building a rear ground floor extension, and have come accross an issue.

To cut a long story short:

Building started on Monday when a building inspector turned up to look at the footings. These were approved and so poured. A different building inspector (didn't get on well with the builder) has then returned today and looked at the manhole which was in full view on Monday, and commented that this has to be moved outside of the extension, and that I am not allowed to build over it.

The plan all along has been to build over it and use a double seal manhole as its a private drain. What they appear to be suggesting is to take the pipes into the drain, outside of the extension (approx 3.5 metres) through the poured footings, and to have a manhole, and then route it back to the drain through the footings again.

I personally don't think this makes any sense as one your adding my pipe work which can lead to more blockages, and secondly is going to cost me a lot extra to get this done now the footings have been poured.

Apparently new legislation was past 2 years ago which says you can't build over a manhole either private or public, is this the case, if not why did the other inspector not pick this up on Monday?

Obviously I don't want to incur the cost and whilst the council have not said no yet, want to know where I stand regarding this to avoid any further costs.

Thanks in advance

Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Thu Aug 07, 2008 3:50 pm


DIY asbestos test kits

Postby geewizz » Tue Jan 20, 2009 11:55 am

Hi Cshaw, sorr i can't help you but would love to know what you were told.
I am in a similar situation in a house i just bought. In this case the extension was built 10 years ago over a man hole that is fed by the four flats above.
The extension is only 3m by 2m and left the man hole accessable. I plan to add a further 2m to the length of the extension, not actually affecting the man hole, but am worried that a building inspector will see the man hole and i will have to knock it all down, leaving me with nothing.
Any info would be appreciated
Gee Wiz
Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Tue Jan 20, 2009 11:48 am

Postby pmgltd » Tue Jan 20, 2009 9:49 pm


You will need to establish whether the drainage in question is a public sewer or a private drain.

If a public sewer, your local drainage/water authority will dictate that you are unable to build an extension over a manhole serving a public sewer. If this is the case you will need to commence consultations with the drainage/water authority as they will control how the alterations are carried out, and may also insist that you pursue a lengthy and costly application route.

If the drainage is a private drain, then I see no reason why you can not retain an existing manhole within a proposed extension. The cover of the manhole will need to be changed to a double sealed screwed down cover, and it would be beneficial to ensure that the drainage below the footprint of the extension is of good quality.

In relation to your Local Building Control Authority - if you have a full plans approval accurately detailing the proposed drainage arrangement then you may have some claim against the Building Control Authority (but this does hinge upon the application being a full plans submission, being approved, and also accurately detailing the correct drainage layout).

Hope this helps
Rank: Apprentice
Progress to next rank:
Posts: 7
Joined: Tue Jan 20, 2009 9:25 pm

Postby TheDoctor5 » Fri Jan 23, 2009 8:40 am

Last year 64% of the questions asked in our forum were answered within our DIY project pages at The project pages are now separated alphabetically and your answers are accompanied by diagrams and the ability to see, and buy, the tools and/or required to complete your project. Use our search box to look for your answer and save a great deal of time and money!
Posts: 1382
Joined: Tue Jan 20, 2009 9:17 am

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics