How Much Mortar Do You Need For A Patio?

[colclough1981]

My mum is planning a new patio, and one of the quotes she's considering says that because of the light use and light footfall, she won't need any hardcore, and just 2" mortar below the flags.
Does anyone know if this sounds about right, please?
She doesn't want a bodged job, but the patio will only be small with not too much use?
Thank you.

[woofgang]

I am no expert but its not the use, its the drainage and earth movement that will wreck the patio. I'd be getting another opinion.

[The Builder]

I guess they're being laid on ground where the turf has been stripped?

If a good hardcore base (at least 100mm (4"), but 150mm (6") is preferable) is spread and compacted, that would be considered a much better base.

On top of that, concrete could be laid, and the slabs bedded on with a few dabs of mortar.

What's often done is to just use 2" of compacted sand instead of the concrete. This is ruled off straight, and the slabs placed directly on to it.

There are other favoured methods, but simply laying mortar on the topsoil/subs-soil would not last long. Traffic, heavy or light would not matter. The self-weight of the slabs plus natural settlement would result in gradually sinking, creating a far from level finish.

A patio, as with anything else, is only as good as its base Colclough :o)

[tezestwing]

Hi
If the area has been turf,for a number of years and so is settled, then as long as you only remove the top turf and layers by cutting in horizontal way (not digging down) the turf plus 50mm for sharp sand + thickness of slabs so as to retain previous levels then as TB said do what is often done,with a sand screed bed,but only for walking on,and sizes to comply with rules and regs etc. HTH Tez

[colclough1981]

Thank you all for your answers :)
TheBuilder, thank you for all the info! The new patio would be laid in place of an existing patio, rather than on turf, would that make any difference?
Thank you again :)

[tezestwing]

Hi
There is a lot more info now, Do you say that you are going to remove old slabs and relay new, so if you find that it was on good foundation hard core ?, just clean away all old mortar if any or put aside old sharp sand to (re use if you can) add to if needed, then just do as TB said 50mm ruled off level and put the new slabs on that .
That is a lot easier and cheaper than a mortar mix , method.
But if you are going to lay on top of exiting then you will defo need mortar mix to maintain levels, but maybe not as thick as 50mm to bed onto levelled hard core.
HTH Tez