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A question about a manhole.

We want to have a small extension build linking
up to our kitchen.
It would mean that the extension would be build
right over an existing manhole.
Are we allowed to do this when we make
sure that the manhole is easily accessible?
Or is this not allowed and we would have to
move the manhole?
Thanks in advance for your replies.

5 Answers from MyBuilder Extension Builders

Best Answer

Hi Dorjeking,

Yes you can have and internal manhole cover. It will need to be accessible (i.e under carpet of lino) and it will need to be a sealed type to stop smells coming through.

Hope this helps.



Answered 17th May 2019

Hi Dorjeking
There are few options. You need to ensure manhole is only serving you.
If that manhole is mains drain run then you cannot build floor over it without build over agreement in place.
If it is only serving your property then best way is you give roding access outside of new extension and seal tight as above mentioned by Andy, roding access chamber will assist you in future for any blockage to clear with out ripping off floorings. Thank you


Answered 18th May 2019

The most obvious first question is, can you divert/ relocate the drain run away from the new build?
Ok, so it maybe you have more excavation to do, and perhaps 2/3/4 inspection chambers to install ( where the drain run changes direction, you must have access to clear drains/ inspection).
If no, then once you have a build over agreement from the water company concerned, then you can seek the best way round the problem with you, your builder, your architect ( if one), and last but not least the main man ( local authorities building inspector).
Alls not lost, common sense and logistics will prevail in the end.


Answered 31st May 2019

This will depend on your local council, water authority and building regulations,
To my knowledge internal manholes are frowned upon and are definatly not allowed in SW London


Answered 21st May 2019

best practice to relocate the manhole , its not difficult.
Ian Hamilton

Oliver design


Answered 3rd Jun 2019

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