Whacker plate on 22mm indian sandstone.

Frere Jacques

I am hoping to lay paving on dry sand screeded on a hardcore base. The plan it to use a whacker plate with a rubber skirt to compact the slabs onto the sand. Can this be done or would the slabs crack, specifically at the corners even on a properly screeded surface?
TIA.

paddy147

Frere Jacques wrote: »

I am hoping to lay paving on dry sand screeded on a hardcore base. The plan it to use a whacker plate with a rubber skirt to compact the slabs onto the sand. Can this be done or would the slabs crack, specifically at the corners even on a properly screeded surface?
TIA.

You need a bed of mortar for laying the sandstone,and then you level it with a rubber mallet.

Frere Jacques

Cheers Paddy.

I'll have the get the whacker plate anyway for the hardcore but what you say makes sense for the thinner sandstone.
Maybe 50mm compacted hardcore,25mm compacted sand, 25mm mortar and slab on top.How does 5mm excess mortar sound under the slabs for tapping down?
Thanks a lot.

TheLastMohican

Whacker plate + Indian Sandstone = Crazy paving

Frere Jacques

Now I'm thinking there is no need for the sand if I'm going for a full bed of mortar, I can just put the mortar on the hardcore.

paddy147

Frere Jacques wrote: »

Now I'm thinking there is no need for the sand if I'm going for a full bed of mortar, I can just put the mortar on the hardcore.

Yes,as long as the hardcore is fully compected then just put down your 4-5 blobs of mortar,lay patio slap and then tap down and level it off with rubber mallet and a spirit level.

Make sure to allow for your "fall" so that rainwater runs away from the walls,house or garage/shed.

Frere Jacques

Cheers Paddy,
I think I'll go for a 40mm thick full bed of semi dry 8:1 though. I've seen pics of porous sandstone laid with dabs and it seems to draw the moisture up on those spots.
Thanks for the tips.

crockholm

Spread the mortar around before you lay the stone,anywhere the stone and mortar don't touch is a weakness. And use a much weaker ratio of sand/cement when mixing,most builders use 4:1 when doing brickwork,but a weaker mix(8:1 or 10:1) would suffice for paving

Frere Jacques

Thanks Crockholm,
Will do. I'm going to screed the semi wet mix first to the lenght of the largest slab in a row and keep doing it that way.