Block paving is mostly joints, not surface
A typical London block-paving driveway has hundreds of joints packed with kiln-dried sand that locks the blocks together and stops them rocking under a car's weight. A pressure washer set for plain concrete will blow that sand straight out of the joints, and a driveway left like that starts shifting within a few months of traffic.
We run block paving at a stepped-down pressure and always plan the re-sanding pass into the same visit where it's included, brushing new kiln-dried sand in and compacting it once the surface has dried rather than leaving empty joints behind.


