How To Lay Block Paving
Block paving is a versatile and durable choice for driveways, patios, and pathways. This guide provides a professional, step-by-step process for installing block paving that looks great and stands the test of time.
Key Takeaways
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Sub-base stability: A properly compacted sub-base is the most important factor in preventing ruts or sinking.
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Edge restraints are vital: Without secure edge restraints, your blocks will spread and your paving will fail.
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Sand layers: You need a solid base layer of sharp sand for bedding and fine kiln dried sand for the final jointing.
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The “Fall”: Always maintain a gradient (at least 1:80) to ensure surface water drains away from your property.
What is block paving?
Block paving is a method of creating a hard surface using individual concrete or clay blocks laid in a specific pattern over a compacted sub-base and sand bedding layer.
What is block paving?
Block paving is a method of creating a hard surface using individual concrete or clay units laid in a specific pattern over a compacted sub-base and a bedding layer of sand.
Materials and Tools Checklist
| Category | Items Needed |
| Base | MOT Type 1, Wacker plate |
| Bedding | Sharp sand |
| Paving | Paving blocks, Edging stones |
| Jointing | Kiln dried sand |
| Layout | String lines, Pegs, Spirit level, Straight edge |
| Tools | Block splitter, Rubber mallet, Soft brush, Concrete mix |
Step-by-Step Installation Guide
1. Preparation and Excavation
Mark your area with marker pegs and string lines. Excavate to the required depth (usually 200mmâ250mm). Ensure you account for the depth of your sub-base, sand layer, and blocks while maintaining a consistent slope for drainage.
2. Install the Sub-Base
Lay a 100mmâ150mm layer of MOT Type 1 across the excavated area. Compact it thoroughly using a plate compactor (wacker plate) until the surface is rock-solid and level.
3. Set Edge Restraints
Install your edge restraints along the perimeter. These are essential; they “lock” the blocks in place. They should be set in a concrete haunch to ensure they do not move under traffic load.
4. Lay the Bedding Layer
Spread a 50mm layer of sharp sand over the sub-base. Use screed rails and a straight edge to level it precisely. Do not walk on this surface once it has been screeded.
5. Lay the Blocks
Start laying your blocks in your chosen pattern (e.g., herringbone, which is structurally the strongest) starting from a corner or a straight edge. Use a block splitter to cut blocks for the edges where necessary.
6. Jointing and Compaction
Sweep kiln dried sand over the entire area. Use a plate compactor to vibrate the blocks into the bedding sand. The vibration will cause the kiln dried sand to fall into the joints. Sweep more sand into the joints and repeat the process until the gaps are completely filled.
Common Mistakes to Avoid
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Skip Compaction: If you don’t compact the MOT or the final paving, the surface will sink unevenly.
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Too Much Bedding Sand: Keep your sharp sand layer at 50mm. Too much sand will lead to an unstable surface.
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Wet Jointing Sand: Only use dry kiln dried sand. Damp sand will clump and fail to fill the narrow joints properly.
FAQs
Can I lay block paving on top of existing concrete?
It is generally not recommended as it creates drainage issues and usually sits too high against damp-proof courses. It is best to excavate.
Why does my paving have weeds?
Usually, this happens because the joints were not filled completely with kiln dried sand or the sand has washed away over time.
When should I call a professional?
If your project involves significant changes to drainage (e.g., installing ACO channels) or working on a steep slope, professional installation is advised to prevent structural failure.
