Subsidence under tarmac - Should I re-surface tarmac with a history of subsidence?

[80-1096815240]

I have a tarmacked drive which is shared with a neighbour. The drive length is about 15 metres straight to my garage and dropping maybe a metre. There is a branch off to the neighbours’ garage and another to my front door. The whole area is about 180 square yards. The area has been subject to subsidence – both houses and garages have been underpinned c25 years ago. The drive is original about 32 years old. Unsurprisingly, it is littered with irregular cracks that seem to originate in the underlying concrete. In front of the neighbour’s garage there is clear evidence of subsidence in the drive, where it has dropped, probably, by a foot and recently a hole has appeared in the tarmac, adjacent to a soakaway, showing a 2 inch separation of the concrete joint and a hole underneath c18� deep and, at least, 3 foot wide.
One contractor proposes to cut out the centre of the subsided area (about 6 feet square - but more if necessary when he digs it out) and fill it, fill and seal the cracks then put on a new tack/wearing course.
A second contractor says this wouldn’t be satisfactory and proposes to dig the whole lot up and start again laying a sub-base of crushed concrete.

My questions are:
Is simply re-surfacing a false economy as presumably, the cracks – and there are a lot of them – will re-emerge?

Given the subsidence problem and the possibility of further movement under the drive, is tarmac a sensible approach anyway or should I go for blocks?

[TonyMcC]

I tend to favour the second contractor. Cracks will probably be reflected through to the new surfacing, and if you've holes appearing due to failing soakaways, subsidence for whatever reason, and god knows what other problems, using the 'sticking plaster' approach proposed by the first contractor seems like a false economy to me.

If this were mine, I'd be much happier to have the lot dug-up, the subsidence and drainage problems resolved, and a new sub-base installed before carrying out re-surfacing of any description.

If there is an on-going concern about movement or subsidence, then an elemental form of paving, such as block paving or flags, is a safer bet than a monolithic surface such as bitmac or PIC. Then, if there was to be any further movement, at least you can repair the damage invisibly and at minimal cost.