Slabs on concrete revisited - Laying slabs on concrete

[tnk]

Hi folks,

I have a new home and want to lay a patio (10 mtrs by 5 mtrs) plus also want to have a a flagged pathway all round the garden. Because I'd like to do this gradually (because of time restraints and because I cannot afford to buy all the flags in one go), the master plan is to scim off 2-3 inches and lay a 2-3 inck sharp sand cement mix on to the firm soil, smooth it all off and lay the flags over the concrete in my own time.

The question is, if the concrete raft is smooth enough, can I just lay the flags loose on the top without having to bed them in on a further layer of sand. Or would a dab of Gripfill on the corner of each flag do the trick.

Cheers


Tony

[simeonronacrete]

The professional way to do it is to use a thin bedding mortar of cement, sharp sand, Ronafix and water.

Mix Ronafix and water, 1:1, and add enough of this to your cement:sand to give you a suitable consistency mortar.

Wet all surfaces with clean water, remove puddles, bruch a bond coat of 1:1 Ronafix:cement o concrete and underside of slab, lay your mortar (min. 6mm) and put the slab on top. Tamp to compact and leave 24 hours. Voila, set solid and won't shift.

Good luck.

[Tony McC]

There's so much variation in flag depth, especially with wet-cast products, that laying them onto any bed of less than 12mm (assuming there's a more substantial base beneath) is impossible. GripFill is a nonsense idea that simply won't work, I'm afraid.