Repair advice

[bigwest]

Always a bit wary of taking on repair work to existing paving so would really appreciate any advice/thoughts on the following. unfortunately I didn't take any pictures but will try and explain the situation as clearly as poss.

Basically it's a clients Mum who has a large patio, sounds like it's been a problem from day one, the pointing has been re-done a couple of times and the area she asked me to look at has been re-done once already. It's an accident waiting to happen, she's 80 years old and I'd like to help if i can.

This area, approx 2m x 4m is at one side of the patio which comes out from her house and is on a corner so has two edges that meet a flower bed on one side and sleepers on another.

Basically all the slabs in this spot have dropped/come loose. There is a section of slabs next to the house that are fine and then the others drop about 2cm. I managed to ascertain that the ones that are Ok are laid over an existing concrete base, and the drop line clearly runs along this line (OK one side, dropped the other).

I lifted a couple of slabs and they appear to have been laid on about 4 inches of mortar, which is very yellow so possibly has building sand in it? Underneath this I'm not sure and may have to do more digging but I couldn't find any type of crushed stone base or concrete base.

The client doesn't seem to think much digging out was done to repair the area which was done by a second company and judging by the rest of the patio the initial contractors weren't that hot in the first place.

So my big question is of course whether the dropping and loose slabs can be put down to bad practice in terms of how they have been laid and could be remedied if done properly, or if it's down to movement in the soil (clay based). There is a big pine tree about 5 metres away from one edge although there are other slabs between the tree and this area that are fine.

I hope that's clear and would really appreciate your thoughts, I don't want to just re-do it for the problem to happen again but to me it looks like the area was never laid properly and I don't think the tree is causing the problems.

[local patios and driveway]

I think you have answered your own question. Sounds bodged, needs to be done right

[London Stone Paving]

No sub base, yellow building sand used for the bedding layer. its been bodged for sure