Laying Paving Stones

Criteria

Weight of traffic
Some pavers can only withstand pedestrian use. Others will take light vehicle traffic. Even stronger pavers will handle heavy vehicles. Check the specifications with PlaceMakers.

Paver shape and size
Your choice should suit the size and shape of the area being paved. Laying pattern: Again, this should suit the area being paved. Laying options include: 45 degree herringbone, stretcherbond, basketweave, soldier courses along the edges

Check the manufacturer’s recommendations.

1. Digging Out

A. Determine the finished level of the highest part of your paving. Against buildings, that should be at least 150mm below the level of concrete floors,  or below the ground level under timber floors. From there, your paving should slope between 15mm to 30mm per metre away from the building. This prevents puddling or running under buildings.

B. Dig out the area to be paved to the combined depth of the three layers, i.e. pavers depth plus bedding sand and base course depths.

• Paver thickness is set by the expected weight of traffic.
• Bedding sand is to be laid loose but compacted to achieve a depth of 30mm.
• Base course is the only variable. It is the foundation of your paving. The thickness of the base course depends on the firmness of the underlying ground, or “sub-grade”. Soft sub-grade has to be dug out deeper because it needs a thicker base course than hard sub-grade. To test the sub-grade, dig down to about 200mm in several places within the planned paved area, then test the hardness of the sub-grade by walking on and stamping your heel into it. Refer to tables over-page.

2. Preparing the Sub-grade

Even after excavating, the sub-grade might have holes that need filling to bring it up to the desired level. Fill these with base material, and compact in layers no more than 100mm thick using a plate compactor or a rammer for small areas. Thorough compaction is vital especially at edges. The finished sub-grade level should be within 20mm of the contour of the finished paving.

3. Preparing the Base Course

This should also be laid in layers no thicker than 100mm and compacted to a uniform dense condition, especially around manholes and kerbs. The finished texture of the base course should not allow bedding sand to filter through. The final surface of the base course should match the contour of your finished paving with no bumps, and no holes deeper than 10mm.

4. Placing the Edging

Edging is important to prevent sideways movement of pavers, and to stop bedding sand leaking out.

Edging options

• Soldier Course of either standing or fl at pavers (see below)
• Paving Kerb – segmented raised kerbing
• Paving Edge – concealed, underground PVC strip
• Haunching – concealed concrete strip (see below)

5. Preparing the Bedding Sand Base

Bedding sand supports your pavers, but will not hide irregularities in the base course. It should be coarse river sand (not beach sand), and damp but not wet.

1. Don’t compact bedding sand directly. It compacts under the pavers. To test how much the thickness will reduce, spread some sand over a small area. Lay a paver on top and thump that with a rubber hammer. The resulting reduction in sand thickness will tell you how much your sand compacts.
2. Pave in manageable sized areas. Spread sand only over an area you know you can finish in one session and get to without walking on. Spread the sand to slightly more than the depth your rubber hammer test indicated would produce a compacted sand depth of between 20mm and 30mm. You will usually need to start with the un-compacted sand bed between 5mm and 10mm thicker than its compacted depth.
3. Screed the sand to a uniform level. As with any screeding, you need temporary guides or runners at each side to run your screed board on.

If you have already laid a Soldier or Kerb course, you may be able to use that to support your runners. If the area to be paved is too wide you’ll need to drive pegs, and fix your runners to them, just like concrete boxing (see below).

6. Laying the Pavers

1. Start from the straightest convenient edge, and lay your pavers with a space of 2mm to 4mm between them. Some pavers have spacer nibs which achieve that automatically. The space allows joint sand to penetrate around the pavers. Always start at the bottom of sloped areas.
2. Lay all full pavers first: then cut and lay any pieces. Cut pavers with a  diamond concrete saw, paver splitter (both available from hire centres) or, for  small areas, a bolster.
3. Don’t run vehicles over the paving until it’s completely finished. To get a loaded wheelbarrow across, lay heavy planks down as running boards.

7. Compacting the Pavers

Your pavers now need to be consistently compacted over the whole area. Include a minimum of three passes with compactor each at 90 degrees to each other.

1. For a small area, use a rubber hammer on a short length of heavy timber: say a piece of 150 x 50mm. For most other jobs, use a plate compactor.
2. When the pavers are all compacted, sweep joint sand over the whole area and compact again. The compactor will drive the sand into the joints. Keep sweeping and compacting until all joints are filled.
3. Joint sand should be fine dry plaster sand with angular particles that lock well together. It is also sold as paving sand and some types incorporate a weed preventative.