What manhole cover and frame to buy?

[Dr Mike Oxgreen]

I need to replace a manhole cover whose plastic frame has broken up, and the mortaring has completely disintegrated. The cover is totally loose and it's very dangerous.

But I'm confused about what to buy. I've been told that my existing manhole cover isn't really intended for vehicular weight. Looking on Wickes' web site I've found this 5 ton galvanised manhole cover with frame, but the notes say that it's not suitable for anything more than pedestrian access. So why is it described as 5 ton?

I need something suitable for a gravel driveway - cars and possibly vans up to about Transit size.

What should I buy?

[V8RX7]

Personally I'd go for this:

https://www.plastics-express.co.uk/underground-dra...

You put gravel in the top so it's almost invisible

[babelfish]

Dr Mike Oxgreen said:

I need to replace a manhole cover whose plastic frame has broken up, and the mortaring has completely disintegrated. The cover is totally loose and it's very dangerous.

But I'm confused about what to buy. I've been told that my existing manhole cover isn't really intended for vehicular weight. Looking on Wickes' web site I've found this 5 ton galvanised manhole cover with frame, but the notes say that it's not suitable for anything more than pedestrian access. So why is it described as 5 ton?

I need something suitable for a gravel driveway - cars and possibly vans up to about Transit size.

What should I buy?

I'd think it's a mistake on the Wickes website, same thing from Travis Perkins (part of the same group I believe) says ok for domestic driveways https://www.travisperkins.co.uk/Clark-Drain-Manhol...

[Dr Mike Oxgreen]

V8RX7 said:

Personally I'd go for this:

https://www.plastics-express.co.uk/underground-dra...

You put gravel in the top so it's almost invisible

Looks good, but would require a lot more work to install compared to a like-for-like replacement, and I just don't have the time.

babelfish said:

I'd think it's a mistake on the Wickes website, same thing from Travis Perkins (part of the same group I believe) says ok for domestic driveways https://www.travisperkins.co.uk/Clark-Drain-Manhol...

Ah, yes. Perhaps you're right. I'll go and have a look at that product in Wickes and see what it's like in the flesh.

Edited by Dr Mike Oxgreen on Saturday 18th February 03:29

[Dr Mike Oxgreen]

Right, I've done the job using the manhole cover and frame linked to above.

On my first attempt, I did a poor job and didn't get enough mortar underneath the plastic frame to support it. After 48 hours, I put my weight on it and it flexed downwards under my weight. D'oh!

I could feel there was a gap under the inner edge of the plastic frame, so I made up some more mortar and packed the gap as best I could. I then added more mortar and smoothed it to blend into the brickwork below.

It has now had another 48 hours, and it no longer flexes under my weight. Yay!

But I've lost confidence in the quality of my job, and I'm slightly nervous about driving a car over it. How can I test its load bearing capacity? Or how can I mitigate against the risk of it collapsing under the weight of a car and leaving the car stuck in the hole?

I have about six bags of sharp sand, so could stack those on top of it to test it. But that's probably only 150kg max.

The other idea I've had is to temporarily put something down into the drain underneath the cover to stop it collapsing too far into the hole in the event that it's not strong enough. The drain is only about 2 foot deep with an open channel, so I've contemplated stacking my bags of sand down there, to a level about an inch below the cover. But I'm not confident I'd be able to lift them back out again from that depth.

Or could I construct some kind of frame with wood? Or should I just "man up" and drive the bloody car over it to see what happens?

What would you do?

[wolfracesonic]

I think you're unduly worrying: As long as you've got a solid, continuous bed of mortar under the frame and it's centered on the brickwork below you'll be fine.






Is it a nice car?

[Dr Mike Oxgreen]

Well, I have a choice of cars to test it with. A tatty SEAT Ibiza, and a TVR Chimaera.

If I use the SEAT and it gets stuck, that will trap the TVR where it currently is. But if I use the TVR and it gets stuck, it'll be far harder to get a jack under it.

I think you're right - I should just go for it. Perhaps drive a car along the very edge of the manhole to start with, and see what happens (hopefully nothing!).

[wolfracesonic]

I'd go with the TVR, I'm sure you'll know where the towing eye is located

[essayer]

Persuade someone else to park on it then claim on their car insurance if it fails?

[Dr Mike Oxgreen]

[Mr GrimNasty]

Mortar might be set after a day, but it won't be hard, and jumping up and down or driving will damage the bedding!

I'd leave it at least a week, several if I could, before driving over it, if you have some heavy-weight board or planks to protect it then maybe.

[Dr Mike Oxgreen]

Mr GrimNasty said:

Mortar might be set after a day, but it won't be hard, and jumping up and down or driving will damage the bedding!

I'd leave it at least a week, several if I could, before driving over it, if you have some heavy-weight board or planks to protect it then maybe.

Yes, I think that's wise. I won't do anything more until the weekend at least. I think I did the re-pointing on Monday afternoon.

Actually I can get the SEAT in and out by straddling the manhole; it's only the TVR that is currently trapped in, and even then it might just be possible to avoid driving over it. Probably worth the slight hassle for a couple of weeks if it lets the mortar harden.