Recess trays - Laying blocks around recess trays

[NDE]

I am going to fit two recess trays when I bloc pave my drive. Everything I have read suggests that you bed the blocks around the frames in sand and wack them down the same as the rest of the drive. As the frame sides are constructed of thin steel plate would this not mean that the surrounding blocks would be forced inwards pressing the frame against the tray preventing the tray from being removed. I would have thought the blocks around the frame would have to be firmly fixed in cement/concrete. Any advice welcome.

[seanandruby]

It will be OK promise. Most of my manhole covers are placed then concreted into a ground floor slab that has been rebated. I fold some tape a few ml thick and tape one to the centre inside of each cover, tape over the crack and any holes before i concrete. once the concrete is set i slit the tape and the cover lifts easy. some covers come with tiny spacers in a bag but seem to get lost on site

[lutonlagerlout]

we always do them in situ,but the minute the drive has had the final wack ,we take the cover out clean any residual kd sand from the tray and grease it up
they can be a pain to get out later on
cheers LLL