How to replace a channel drain cover?

[jackobss]

At my home there is a 40-metre continuous concrete drain which is 11cm wide. Into this channel has been inserted a plastic channel with a plastic grate. The drain has to be covered because I once stood in the uncovered drain with serious repercussions. I used to be able to remove the grate cover regularly and easily to sweep/clean out the drain. Over the years the grate has become very brittle so that it breaks when being removed. Also the 11cm gap for the grate cover has decreased to 10.5cm. This makes it extremely hard to return the cover when I have finished cleaning and causes the tight squeeze which contributes to the breakage when I try to remove the cover. The channel sleeve is still in good condition but dirt between the concrete drain and the sleeve has contributed to the decrease in gap width. As the sleeve is in good conjdition, I have tried to purchase only replacement covers to rest on top of the concrete "shelves". An expandable cover would be ideal but I don't think that such a thing exists. I can find no covers that are 10.5 or 11cm in width to purchase. A friend has suggested sawing 5mm off the side of each cover so that they will fit but still be stable enough to walk on. I suspect that this would be a big job. To make matters worse, the ends have been broken off the covers when prising them out of the drain so there are now big gaps in between each cover. I thought of putting a Staymesh plastic gutter guard strip in the drain instead of the covers but gutter guard is wider than 11cm, would probably not support weight and would be an aestetic disaster.

Any suggestions would be appreciated.

[jackobss]

Afternoon Dave

I should be out gardening in the forecast sunshine but it is yet to put in an appearance.

I was considering exactly the idea you have suggested. It's amazing what ideas spring to life when one thinks outside the box. There's plenty of flexible hose lying around here that could be used and maybe even a mop head on the end. Thank you yet again for your helpful inspiration. 

The spreading clamp is also a great idea although I think it is the concrete edge that has expanded rather than a narrowing of the sleeve. If the first idea doesn't work, I now have a plan B. Thanks!

Peter