Block Paving

Preparation

Sub-grade:

  • Clear top-soil: complete sub-grade drainage.
  • Excavate and back-fill soft spots: compact well throughout.
  • Protect sub-grade from adverse weather.
  • Lay geotextile fabric or capping layer (if specified/required).

Sub-base:

  • Prepare in accordance with Specification for Highway Works.
  • Lay and compact in layers to a close-textured finish.
  • Open-textured sub-bases may require a binding layer of finer material.

Laying

General principles:

Lay paving immediately on prepared bedding: do not leave bedding exposed to weather or overnight.

To avoid bedding layer damage and creep, lay paving units up slopes and/or away from edge restraints.

Stand on previously laid paving when placing next row.

Block and sett paving

Lay fine aggregate bedding course (to BS EN 12620 Gf85 0/4 mp) to a final compacted thickness of 50 mm (in accordance with BS 7533: Part 3).

This can be done by either:

  • Compacting 50 mm of fine aggregate and screeding a further 15-20 mm of loose fine aggregate. (A small trial area may be required to determine the actual surcharge). Note: this is the preferred method. If laying on a roadbase or previously paved area, recommended thicknesses are reduced to 30 mm followed by 9-14 mm.
  • Or:
  • 60-70 mm loose fine aggregate screeded to accept blocks. Note: 39-44 mm if laying on a roadbase or previously paved area.

Lay blocks hand tight (2-5 mm joints).
Bed blocks with vibrating plate compactor (2 or 3 passes typically required).
Brush-fill joints with fine dry sand (in accordance with BS 7533: Part 3).
Vibrate surface again to assist joint filling.

If necessary during early life, top-up joints with loose sand to within 1 mm of working face by brushing surface.

For Countrysetts (pedestrian):

  • Lay setts in traditional stretcher bond with 6-10 mm width joints.
  • Ram well into bedding.
  • Cut setts as necessary for obstructions etc. (minimum cut lengths: 75 mm): dress top arris of cut pieces with a lump hammer to give rounded top edge.
  • Fill top joints with limestone dust (approx. 3-4 mm down) and ram down.
  • Alternatively, use weak dry sand/cement mix, 1:9 mix). Note: to prevent mortar staining, keep setts dry during joint filling.
  • Sweep clean, then moisten with watering can fitted with a medium rose.

For Countrysetts (vehicular-cube):

  • Lay as traditional granite setts on minimum 100 mm of ST1 concrete.
  • Bed on 25 mm Class 1 mortar with 6-10 mm class 1 mortar joints.

For Woburn:

  • Lay setts in Herringbone pattern if heavy duty (80 mm) version is specified for regular/heavy traffic applications.
  • Complete as for block paving.