Mixed thickness paving - sequence of work? - 80mm blocks, and 50mm flags

[Blagard]

The 80mm Block paving I will be putting down will have single independant flags inset.

The block is 300 x 200 80mm thick. The Flags are 900 x 600 approx 50mm thick.

I am not sure of the best sequence in laying the Flags.

First idea is to use a 900 x 600 former. Lay the blocks as usual and when the former is surrounded, lift out, top up the sand and position the Flag.

Second idea was to use the former and then with three side done top up sand using a temporary restraint on the open side and fit flag. Having the ability to slide it a little and help bed it down. Remove temporary Restraint and continue with blocks.

I will in any case do a test area to see how much higher the Flag needs to be initially to allow for the thicker bed of sand and expected greater settlement.

I don't have any other ideas on this yet, so again, drawing on the experience of those that do, have you a preferred and proven method ?

[lutonlagerlout]

if you are going to be laying flags you are going to need a rigid bed as you cannot wack slabs
i would be tempted to use a line and lay them as you go
get a nasty blood blister if you catch your finger trying to drop a flag into a preset hole
BTW 600 by 600s work better for this detail than 900 by 600s
dunno why just look better
BTW welcome to the forum blagard
LLL

[Blagard]

I must admit I have my concerns about a whacker plate going over the slabs anyway.

I have always laid flags on a full bed with some OPC mixed into the compacted sharp sand. But I would not want any OPC in the bed for the blocks!

The preset hole has its problems including risk to my fingers! but if it goes wrong I can remove the blocks to deal with the problem and get the flag out again. Of course once I have the flag in at what may seem a acceptable level, there is not much chance of getting it out whole again if I continue with the blocks.

I now suspect using the open side method and OPC in the top up compacted sand may be better. Setting the flag a few mil below the surrounding blocks and hope I get the blocks down to at least the same level! With the blocks at either end I can use them as rails to get the sand for the flag to a consistant level.

A trail area is I think essential because of the variables.

It is all drawn up complete with the levels etc. and on paper at least, looks good. The 300 x 200 blocks being the same ratio size as the 900 x 600 flags. The Flags are orginals and I am refinishing the surface of them to enhance the granite chips. They have come up brilliantly using a diamond grinding disc.

[Tony McC]

If this was my job, I'd lay the whole area in blocks, compacted but not jointed. Then place the flags on the surface to get the arrangement right and when happy, lift out the blocks and replace with flags on the beefed up bedding.

It may seem like a lot of unnecessary work, but how long does it really take to lay just over a half-metre squared of blocks compared to using formers or the like? It also has the added bonus of allowing the flags to be positioned to a pleasing effect in one fell swoop rather than placing them as you go and hoping the distribution is correct once you're finished.