Properly laid flat top setts, laid on a puddle clay/cold tar bed, with a tight bond, with tar sealed joints, was the top quality system used for city streets between 1750's and 1850's
If modern utility operator's contractors are not allowed to open the road up and reinstate it with no (strong) supervision, or enforcement of repair to the same standards, you kiss goodbye to a road which requires minimal attention for at least 160 years under the most punishing of heavy traffic.
The signs are blatantly obvious - even where tarmac has been laid over a setted street. The load-spreading setts are ripped out and binned, along with the bed of puddle clay or cold tar on which they are laid. Type 1 or Type 2 graded stone is tipped in to the hole with no filter membrane or similar treatment, wit the with loadings that stone migrates into the clay or surrounding weaker subgrade with any water present leaching away the finer material or poaching through load cycles and leaving the 'hole' imprint as a sinking section of the road pavement.
Older forumites might recall the much higher quality of setts on Cockburn Street (my regular 2-3 minute sprint to Waverley for trains in the 1970's). The relaying was a total screw-up using inappropriate NON flat top setts laid with a looser bond, leaving you with a teeth chattering, joint pounding ride with pressure on the arms from braking. An ironic twist that this is potentially a Cockburn Association failure, through not reacting to the refurbishment work using the WRONG road surfacing material, and totally changing the road detail.
The lack of proper delivery on 'repairs' is clearly aparent when you can pick-out the areas in a road (in Glasgow especially - but I have less detailed knowledge of Edinburgh) where tram rails and tie bars were taken out, or the stronger tram track slab sits centrally, with the road edges sinking.
A well built setted or cobbled street has 1-3 courses running along the street at the kerb edge, laid approx 1 cm below the main carriageway, and these form a self clearing gulley (especially when not blocked by parked car tyres) and the slightest shower sees those gulleys working effectively.
Please deprecate the cheap and easy get outs of very loose laid stones with the big joints filed with brushed in 'dry mix' or laid on a bed that rapidly sinks at weak spots - do they not use modern filter membrane equivalents of sheep dag and branders (or just rock on branders as Telford used on canals and causeways - 200 years old and still sound)
A further detail seen on Applecross Street Glasgow and Stirling Old Bridge in one form (long stone wheel tracks on the uphill side to make cart haulage led effort) or the cast kerbs and channels still found in some old vennels and back lanes - far more robust than modern kerbs and designed to guide the cart wheels as well as provide a smoother running surface - the original plateways predating the railway adaptation of this system, and its refinement.
Well laid self clearing gulleys, with long flat stones, AND with either kerb face drainage or continuous edge slot drainage also provide a smooth riding surface - as those riding along the High Street between the Bridges may have noticed.
Another detail where the first renovation messed up was the High Street - North Bridge cross-roads. Lok at any original setted or cobbled junction and you will not see the bond (courses) laid parallel to the direction of traffic, but at an angle. The forces exerted by the traffic, if set along the bond with no offset joints to resist movement = rapid deterioration. Options can include herringbone patterns or triangular blocks of surfacing set at an angle to the main traffic flows
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