Manhole cover replacement

[Tim H]

Hi all. We have a manhole cover in our garden that covers a main sewer line. We want to replace it for a recessed manhole cover and blend it into a new block paving path we'll be adding. The problem I'm having is figuring out the size I need. 

I have read that you need to measure the size of the drain shaft (clear opening). This measures 600mm x 760mm. It appears to be quite difficult to find a replacement of this size. 

Another website that I've recently come across has said that i need to measure the internal size of the current frame. Currently, the manhole cover is a VERY heavy cast iron cover that measures approx. 600mm x 600mm (internal frame measurements). There are no gaps and the weight/appearance of the thing suggests it's the original manhole cover. 

Will I need to search for a 600x760mm manhole cover, is there such a thing as a reducing collar that I should use or, if the current cover is 600x600mm then can I simply remove it and replace it with the same size? Any advice would be appreciated. 

[Conor]

Is 600x760mm the dimensions of the shaft or the biscuit on top? The biscuit should be 600x600. It would be highly unusual that a standard 600x600 lid would not fit on a public manhole.

 

On that topic... The water company own the asset (assuming that's what you mean) and you have no right to touch it, and would need their permission in theory. Up to you how you proceed. Same also applies to paving over the pipe.

Edited May 20 by Conor

[Tim H]

54 minutes ago, Conor said:

Is 600x760mm the dimensions of the shaft or the biscuit on top? The biscuit should be 600x600. It would be highly unusual that a standard 600x600 lid would not fit on a public manhole.

 

On that topic... The water company own the asset (assuming that's what you mean) and you have no right to touch it, and would need their permission in theory. Up to you how you proceed. Same also applies to paving over the pipe.

600x760mm is the shaft. The manhole cover itself is 600x600mm.

Thanks for the info re. the water company owning it. Guess I should ask them just to be sure it won't be a concern in future.