Manhole covers?

[The Medway Handyman]

I look after an office complex & grounds. Outside each building is a pressed steel manhole giving access to the water meters & stopcocks.

One of these frames is badly corroded & the cover is falling in, another is on the way.

Measuring the outside dimensions of the steel frame, they are 475mm x

710mm. There is a concrete filet around each measuring 610mm x 840mm.

I can't seem to find the right size cover & frame. Standard seems to be

600mm x 450mm.

Am I measuring the right thing? Is a standard 600 x 450 manhole not actually that size?

[Brian Gaff]

Round here the mob at Thames Water have beaver away recently replacing metal with plastic, and they look like rather than lasting tens of years, they will last tens of minutes. However they seemed to do minimal fiddling about other than a bit of drilling and cement around the edge, so maybe they get them made specially. Brian

[polygonum]

Might not be what you want, but range of sizes seems pretty comprehensive:

[Unbeliever]

Sigh,

As long as the concrete/brick opening at the top of the manhole is smaller than the cover you want to fit, then simply take the old one up, cut away any bedding under and around it, drop the nearest sized, new cover frame into the hole that's left (enlarging it slightly to fit if needed), level the frame up if needed by using bits of slate etc and then re-bed the thing in with your choice of bedding/finish - sand/cement, concrete, tarmac, spit, mastic etc.

Jeesh! Such a fuss over what really is a simple job.

[The Medway Handyman]

It's bigger, f****it. Haven't grasped the metric system yet, have you?

[The Medway Handyman]

Looks good, thanks. I'll give them a call.

[Martin Brown]

I have the same question although for the moment I am only really interested in my domestic one with pedestrian traffic and size roughly

600x450. I have three manhole covers and they are all random sizes apparently unrelated to the ones listed in their catalogue!

The actual size looks to be more like imperial 24.25" x 18.5" or in metric 617mm x 470mm the frame it is in is about 5mm gap from this. (and might well be rusted to hell if I lifted it out so I don't want to disturb anything until I have a replacement unit in hand)

I presume modern ones really are exact metric sizes in which case can anyone suggest where I might get a new Imperial sized lid from?

[polygonum]

A few years ago I had similar situation and bought a standard 600x450, ripped out the old cover and its frame. Then mortared the new frame in place, left it overnight, and dropped the lid in place. Lovely.

A few months later, we decided to cover the area with block paving so replaced it with one of the ones which takes blocks...

[John Rumm]

He would be dropping a clanger - literally, aa the whole thing fell though the hole!