Replacing concrete manhole with grass-top cover

[Apnomis]

We have two rather unsightly concrete manholes in the middle of our lawn that we would really love to do away with. Due to the position of them it is impossible to hide them under a planter or in a path etc and the only viable option is to replace the covers with grass-top covers that I have seen advertised on the internet.

Unfortunately these concrete monstrosities were installed in the early 80's before the metric system took hold of the UK and the 'clear opening size' measurement of the hole is 18"x24", the actual shaft is larger than this as there is quite a thick concrete border around it.

Having looked at the various grass-topped options available the common size seems to be 600mm x 450mm, but on the face of it these wouldn't fit?

Does anyone know how to properly measure the size of a manhole and whether it is possible to retrofit a metric manhole cover on an old imperial one?

Has anyone replaced their old concrete manhole covers with new metric recessed ones?

I just need some advice - I'm happy to employ someone to fit them, but people I've called don't seem to offer it as a service so I'm going to need to buy the covers myself and then get someone to fit them as I'm lead to believe it's exactly the same as fitting any manhole cover - and I've definitely seen these old style concrete manholes replaced with modern metric recessed ones when people have block paving laid for example...

Any advice would be welcome (was in two minds whether to post it in this section or the building section)

 

[bernardgreen]

Has anyone replaced their old concrete manhole covers with new metric recessed ones?

Mine was replaced by Anglian Water free of charge. Free of charge because it carried sewage from other properties as well as from mine. As it serves more than one property the manhole is the responsibility of the water company even though it is on my property.

 

[Apnomis]

Has anyone replaced their old concrete manhole covers with new metric recessed ones?

Mine was replaced by Anglian Water free of charge. Free of charge because it carried sewage from other properties as well as from mine. As it serves more than one property the manhole is the responsibility of the water company even though it is on my property.

Not sure what mine carries - problem is there is nothing wrong it with - I just want it changed for cosmetic reasons so I'm not sure I could get anyone to pay for mine...

 

[r896neo]

Really with manhole covers the size is irrelevant as long as it is big enough to be fully supported by the edges. You would find that many covers on older brick built chambers overhang the edges here and there.

You could happily lay a 600x600.

As long as you dont obscure the opening and make it smaller by fitting a smaller cover your fine. Obviously fitting extra large ones is daft for cost and aesthetic reasons.

Be aware that recess cover are much deeper than normal so you may need to remove a course of bricks from manhole chamber to lower the cover or if its a precast concrete chamber cut it down lower.

To be honest in the past with some of the large 600x900mm concrete covers i have with the consent of the owner buried them in lawns as precast concrete ones can be a real pig to adjust and you can not get a recessed cover big enough.

In case access is needed in the future we buried them only 3 inches deep, marked the location and you can easily find them with a fork push into the grass and strip the turf to access.

Its a compromise if and when you do need into it but worth it for the aesthetic improvement.

 

[r896neo]

If it is shared then you must not bury it and probably need the water authorities permission to even change the cover.

 

[freddiemercurystwin]

If it is shared then you must not bury it and probably need the water authorities permission to even change the cover.

Technically, but millions have been.