Hi I’ve recently had a sandstone patio laid on compacted type 1 with wet bed by a landscaper. The last few days white marking is appearing on the slabs, if the slab is wet, these marks appear back really quickly, has anyone any idea what they are, what caused them and if they can be removed? thanks Shaun
Thanks, one of the slabs cracked so it was lifted, is this what a full bed of mortar should look like?
I think the Black is some kind of mould. Seen it many times on a lot of paving slabs. I jet washed a patio for a friend, but it came back a few weeks later. Maybe the slabs need sealing? Personally I five dot the mortar, that way it gives more movement when setting the slab down.