Extension built over a manhole cover

[kirinm]

As the title suggests. A house we are keen on (offer accepted but we still need to accept ours), has a shoddy extension that a drain survey has revealed is built over a manhole cover. We'd be knocking down the extension regardless but is it true that you can build over them (with permission) if it is accessible? Can a manhole be moved?

These days you cannot have a man hole in the extension. But they can be moved and you can build over public sewer pipes as long as there is access from elsewhere. Read about build over agreements on your local water boards website.

Extension presumably has no permissions etc? I'd walk away. It's a sign of how much care they have taken over the house. If you are considering going ahead, get a really thorough structural survey including roof and any loft.

I would check this very carefully - we weren't allowed to build over the manhole cover just outside the back door when we built our extension a couple of years ago so we had to go round it and put a little door in for access.

Sorry if this is long!
What exactly is the manhole covering? Sewer or just water?
We just went through this process! We had a manhole outside the back door and wanted to build a conservatory over it. Every conservatory company said they would just build a little hatch inside the conservatory floor, to allow access IF ever required.

Ours was a sewer and the conservatory advised us to apply for a build over agreement with the council. IF it had solely been sewerage from our house, apparently this and the viewing hatch would have been sufficient. It turned out that it was a sewer for the entire street of houses, with each house draining into it as it went down the road behind each house. We were at the end of the road!

We had to pay for a copy to put a camera down the pipe to check the bends/shape/size etc. We then had to cancel the build over paperwork and apply to change the course of the sewer to then be moved around the outside of the conservatory. We needed the sewer company to do this and it cost ££££'s, including the additional council fees for inspections etc. Plus it added at least 2mths waiting approvals etc.

If yours is just water, it might be ok, but I'd be very cautious if its a sewer and would walk away!