External drain chamber - manhole cover

3 Jan 2009
Reaction score
Hi all, I had an original cast-iron manhole cover over my foul drain chamber, in my garage. This cover broke (cast iron is brittle...) and I want to replace it. The original cast-iron frame seems to be in reasonable condition, and well fixed into the rebate round the top of the chamber, so I'd prefer to re-use it rather than knocking it out and having to re-cement a new frame in etc etc. Is it possible to find a modern eg. galvanised steel, direct replacement for the cover only, which will fit over the 'lip' of the existing frame? I've tried but not having much luck! Seems weird that no-one else would seem to find this an easy solution and someone would supply them?!

Thanks for any info.

(See photo of the existing frame - the chamber is a standard 600 x 450mm 'opening' but obviously the lip on the frame means a new cover would have to be approx 10mm wider in every direction).


  • PXL_20220508_160745402.MP.jpg
    510.8 KB · Views: 51
Sponsored Links
Sponsored Links
It'll be more by luck than judgement if you find something to fit, but even then I doubt it'll seal as well as the original cover. Also the issue of loading, thin steel covers will soon bend if any sort of weight passes over them. To be honest, you'd probably be better off biting the bullet and replacing cover and frame with something suitable for the location, if vehicular traffic is going over it, then something capable of taking the loading.

Guide for reference here: Manhole cover sizes and load classes - Drainage Superstore Help & Advice
  • Thanks
Reactions: CBW

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local