Stone paving thickness

[Self-builder001]

I'm being told that a relatively hard limestone (Moleanos, from Portugal) can be laid externally in 15 mm thickness (the slabs are 600 x 400 mm). The saving is of the order of £2/m2 compared to 20 mm thick slabs (from a different supplier).

On this forum, the advice seems to be not to go below 18 mm. Does this advice depend on the type of bedding used, the hardness of the stone used ... even the size of the individual slabs?

If 18 mm is a minimum under all conditions, I should clearly decline the offer of the 15 mm slabs and go for the 20 mm thick slabs.

Thanks for any advice.

[Rich H]

Even 20mm is very thin for paving slabs, but for only £2/m2 I'd definitely prefer them over what are basically tiles.

[IanMelb]

Is that a £2/m2 saving or £2/m2 all up price?

[Rich H]

Saving by the sound of it.

[IanMelb]

Reading it again, I think you're right

[DeckmanAdam]

I personally would pay the extra and go for the thicker ones...i too have the options of buying the thinner slabs for cheaper like you have but the depth your stating there is far thinner.

[Tony McC]

Thinner flags means more breakages. Saving 2 quid per square metre might not seem like such a good idea when you find that 20-30% of them are cracking when laid.