Reusing sub base for new patio?

[F54Mini]

Hi

We currently have 40sqm of block paving in the back garden which we want rid of, it doesn’t look great and it’s a pain to keep weeds and other gunk off it.

To that end, we want to remove the block paving and replace with sandstone paving.

I am hoping we can pull up all the block paving, remove all the sand to leave the sub base and then pave straight onto that?

Unsure of the existing sub base thickness but it’s held the block paving for 10 years without sinking anyway so assuming it’s adequate for slabs

Cheers

 

[Mr diy a lot.]

Yes sub base may well be solid and in good shape with not need to redo. But check by exposing a small area so you can see a cross section. Once blocks and sand are away you might what to hire a whacker plate again to pack everything down nice ready to take the full wet mortar bed for the sandstone. Remember to make up some slurry primer for the back of the sandstone slabs before you lay each one or they might not all stick down well. Don’t want half of them coming loose in a year or two. !

Also check you achieve a 1 in 80 gradient ratio so you don’t get any water lying

 

[JohnD]

Sandstone slabs need to drain well (and not be in a shaded area). If they are damp they will IME get black mould. There is a big difference between my neighbours slabs (laid flat between walls) and mine, with an extra gradient so rain runs off to the lawn, carrying loose dirt away. I went for the redbrick surround which I think sets them off well. IIRC I have half an inch of fall per yard, a little more than usual, because my neighbour's look so bad.

 

[Mr diy a lot.]

Mm