Screed or wet bed for sawn rainbow sandstone 40mm? - More advice needed please

[deegan1979]

Hi guys. Well it's that time for me to attempt to lay my slabs.
Been having a good look online but can't seem to find info on the best bed for 40 mm sawn rainbow sandstone slabs.
Some say a screed bed others say a wet bed, anyone offer any advice?
also is a bond bridge primer slurry only required on a screed bed or can it be used on a wet bed aswell?
Many thanks. Luke

[lutonlagerlout]

luke for all sandstone we use a wettish bed of 6:1 with around 100ml of SBR added to the mix
it has worked for me for over 15 years
LLL