Forum: Block Paving
Topic: Recessed tray manhole cover
started by: dave1965
Posted by dave1965 on 15 May 2019,08:40What is the correct method for installing paving blocks into the recessed tray ? Do I just bed them on sand as with the rest of the drive and compact down with the other blocks, or do I stay away from the tray with the wacker plate ?
Posted by doobin on 15 May 2019,16:55Stay away with the wacker, it'll just bounce. Sand can be used if needed to get the levels perfect, but I try to get the tray set perfect and just sit the blocks in with some co-polymer grab adhesive to stick them to the tray.
Posted by dave1965 on 16 May 2019,08:39Thanks for the reply, is there a particular brand/type of adhesive that you would recommend?
Posted by Tony McC on 17 May 2019,14:06Most trays are slightly deeper than blocks so some form of bedding is usually required.
You could use grit sand, same as used for bedding blocks on the main pavement, or even a mortar mix (say 6:1 semi-dry). With a plastic frame, the plate compactor will bounce, so best to assemble the tray on a solid surface and use a mallet to compact blocks, then offer the paved tray into the frame.
When bedding onto sand, I usually drill a couple of 10mm dia holes in the base of the tray about 50mm or so from opposite corners, then line the tray with a permeable, non-woven, construction grade geotextile before placing the bedding and fixing the blocks. This allows any water that finds its way into the tray to also find its way out again and prevent the tray looking damp long after the rest of the pavement has dried out.
Posted by dave1965 on 18 May 2019,07:35Thanks Tony, all makes sense, I will give this method a go. I did wonder about how the tray would drain