Of all forms of hard physical labour, laying block paving by hand is 'by far the most physically destructive', states Tolly Paving founder and partner Terry Pointer. Spading sand and pushing it around a site in a barrow is, over time, back-breaking work. Lifting blocks by hand strains tendons in fingers and forearms - an experienced paver at the laying face will manhandle the equivalent of an articulated truckload of blocks in a day.
Kneeling in wet sand eight or 10 hours a day, five days a week is guaranteed to give a worker rheumatism and arthritis.
'If you start laying blocks at 16 when you leave school, your body's knackered by the time you are 40, ' Pointer says.
These days, however, Pointer's pioneering use of block laying machinery is transforming conditions for his workforce.
Tolly has worked closely with block manufacturer Marshalls and specialist plant supplier Probst to develop a system for laying 0.84m 2'layers' of 80mm deep blocks.
Probst has designed a lifting head, fitted to a small, articulated wheel-loader type carrier, which lifts layers of blocks direct from a 1,200mm by 700mm pallet. The computercontrolled lifting head trues the block layer with blade-like callipers at either end and then grips it, using far more powerful lifting blades, by the long edges.
Marshalls has refined its standard 12-sided interlocked hexagon SQ6 concrete paving block, designed for machine laying, to suit the Probst head. All blocks have a vertical spacer rib moulded on to each edge. On early versions of the SQ6, the spacer was only half the 80mm depth of the block, causing block layers to bow and collapse when lifted.
Spacer ribs are now full height, keeping layers flat and intact.
Each layer of blocks lifted from the pallet is placed as a complete panel on to a mechanically compacted and screeded coarse sand sub-base. The entire laying process is a two-man operation. One person is needed in addition to the lifter operative to precision guide the lifting head - a matter of a quick push or a tug on a pair of purposedesigned handles. Tolly works to within 5mm tolerances.
No manhandling of individual blocks is required, meaning that the incidence of tendonitis among Tolly's workforce is well below industry average. It takes an average of eight weeks for damaged tendons to recover, says Pointer, and his firm generally has two to three of its 40-odd men off with tendonitis at any one time. The only time pavers end up on their knees is to lay blocks in 'fiddly' areas, says Pointer - around drains and against walls.
So Tolly has more of its highly paid skilled men working more of the time - and producing a lot more. At around 100m 2/hour machine paving progress rates are on average six times greater than can be achieved by manual paving, claims Pointer. Tolly's best gangs are eight times faster.
The entire UK block paving market delivers between 2Mm 2/year. It can and will grow dramatically in the next five or so years.
With prospects of a dramatically increased workload, it is vital that machine laying, at present used on only 10% of jobs, is taken up more widely. Not just to meet demand, but to save the pavers from being wrecked by an over-abundance of work.
Work is racing ahead on a 12,000m 2block paving job at client Millbank's loading yard, Brandon, East Anglia.
Marshalls is supplying its standard interlocked hexagon SQ6 blocks and a new 100mm by 200mm rectangular block laid in herringbone pattern.
The SQ6 involves no manual intervention. With the herringbone pattern, however, pavers must manually turn two blocks per panel through 90degrees to achieve interlock with adjacent panels and insert blocks in the inevitable gaps left by the packing that stabilises the herringbone layers on the pallet.