recessed manhole cover indian sandstone

[jd1980]

I have read a good guide for fitting recessed manhole covers on pavingexpert.com, but have some questions.

I am not sure yet if the cover will involve cut flags, I may be able to trim one to fit. Almost certainly I will have mortar gaps to fill. I plan on using brush in resin. I will be laying the flags on full mortar bed sharp sand/cement (also slurry priming the underside of the flags), so this will cover the entirety of the recessed cover before the flag/flags are placed into it.

It seems that most flags placed in the recess are cut to butt up to the edges of the cover and only have mortar gaps if this means alignment with the general patio around it - is this the case or would some resin be expected to fall into what appears to be a very thin gap?

Where does water go that drains into these gaps, of course sandstone and the resin are to some degree also permeable. The full mortar bed would surely class as impermeable so water would not need to drain through that into the drain. It seems if you fill these covers with gravel or similar you would typically drill some holes into the recessed cover?

 

[jj4091]

You are correct in your assumption that resin will fall into the gap between the rim and support so once you have it set up you need to quickly remove the lid and clean all around it other wise when it sets you will need an angle grinder to open it.
Any water that goes down the joints will just drain away down the outside of the chamber, but if you have installed (got enough fall ) it correctly it will just run over the lid rather than drain through the gaps.

 

[jd1980]

Thanks for your reply and that is useful info. My question was more about the inside/ the actual tray itself, where the edges of the flags inside the tray meet the edge. Do you typically butt the flags up as close as possible to the edges, around the handles etc..?

There will be an overall fall (about 1:100 - I know its not 'enough', but that will have to do, for various reasons). I cant see how water wont leak inside the tray as the fall will never be enough, especially with riven flags. Is this just accepted and I guess eventually it finds its way out or evaporates?

 

[jj4091]

I have had another thought about the tray to chamber and, if you want to go that far, you could run a bead of silicon around the corners so that it acts like a rubber seal once it is dry. You could also do the same thing with the tray and flag itself. I've only ever used these trays with concrete but had problems with either the tray or surround rusting so I think you are right about being concerned about having water either sat in the tray or the surround. Having said that I believe you can get a plastic or similar material version in which case you would not have the same trouble