Suuba

How f*cking hard is this..

I have a re-layed the slabs ontop of a skimmed surface with sand and some wet concrete which i put down myself. However after a month or two the slabs start moving about due to my 2 cars going up and down a few times a day...

What can i do to stop them moving, possible fill the gaps between them with concrete to compact them together?

David Lock

With that wonderful stuff hindsight I guess you should have sunk them deeper into the screed. There can't be huge stresses involved so I would do as you suggest with some good strength mortar. Make sure everything is damp/wet when you do it to try and get a good bond and cover with a wet cloth (hessian or similar) for a couple of days or it will dry out too soon.

If the slabs are removable I wonder if a quick splatter of bonding agent underneath might help the cause. This will probably get shifted to DIY and there are lots of experts there!!

Chip Sengravy

Have you not pointed between?

Suuba

One each corner of slab and then point them?

David Lock

I assumed that if they were slipping the bond underneath had gone and you would just be able to lift them up and paint some bond material underneath (no more nails??) ? If that's not the case than I would leave alone and just bung some mortar between the joints - and drive slowly

Edit. Depending on how big the gap is between the slabs I guess you could "cheat" a bit and put in a few short lengths of steel reinforcing bar (10/12 mm dia say) and mortar over these. That should stop the buggers moving! Or cut them short and bang them in as pegs.

Apparition

I take it you have an edge along the front of the driveway? Cemented in, and therefore preventing any movement in future.
Yve