Preparing The Base
Proper base preparation is the most critical factor in the long-term performance of any paving block installation. The base must provide a stable, well-drained foundation that can support the intended traffic loads without settling or shifting. Start by excavating to the required depth — typically 150 to 200mm for residential driveways and walkways, 250 to 350mm for commercial applications, and 350 to 500mm for industrial paving. The depth must account for the sub-base, bedding layer and block thickness combined. Compact the exposed sub-grade thoroughly using a plate compactor or roller, achieving at least 90 percent compaction for residential work and 95 percent or more for commercial projects. Install a geotextile membrane over the sub-grade to prevent the sub-base material from mixing with the soil below. Then place and compact the sub-base material — typically hard crushed stone or quarry waste — in layers of no more than 150mm, compacting each layer thoroughly before adding the next.
Laying Paving Blocks
Once the base is prepared and compacted, laying the paving blocks can begin. First, spread a bedding layer of sharp sand or stone dust to a thickness of approximately 40 to 50mm, screeding it to the correct level using levelling bars and a straight edge. The bedding layer should be lightly compacted but not fully compacted at this stage. Begin laying blocks from a fixed edge or straight reference line, placing each block firmly onto the bedding layer with a slight twisting motion to ensure full contact. Maintain consistent joint gaps of 2 to 5mm between blocks, using spacers if necessary for patterns that require precise alignment. For driveways and vehicle areas, lay blocks in a herringbone pattern for maximum structural stability. Work in a systematic manner across the area, ensuring that the surface remains level and true as you progress. Use a long straight edge and spirit level frequently to check the surface for dips or high spots, adjusting block positions as needed.
Cutting And Fitting
Cutting paving blocks to fit around edges, curves and obstacles is an essential skill for achieving a professional finished appearance. For straight cuts, a block splitter or masonry guillotine provides clean, accurate results and is the preferred tool for most installations. For curved cuts and notches around pipes or drainage channels, an angle grinder with a diamond cutting disc is required to achieve the necessary precision. When cutting blocks, always wear appropriate personal protective equipment including safety glasses, gloves and dust mask. Cut blocks should fit snugly into the surrounding area with a gap of no more than 5mm, which will be filled with joint sand. For curves, you will need to cut wedge-shaped pieces that taper from full width on one side to narrow on the other — this requires careful marking and cutting to achieve a neat fit. Plan your cutting positions in advance to minimise waste and ensure that cut blocks are placed in the least visually prominent positions where possible.
Edge Restraints
Edge restraints are essential for preventing paving blocks from spreading or shifting under traffic loads, particularly in vehicle areas. Without proper edge restraints, the blocks at the perimeter of the paved area will gradually move outward under the pressure of traffic, causing the surface to lose its integrity and creating gaps and uneven areas. Edge restraints can be constructed using concrete haunching (a continuous concrete kerb cast along the edge), precast concrete kerb units, brick-on-edge restraints, or galvanised steel channel restraints. For residential driveways, a concrete haunch at least 100mm wide and 150mm deep is typically sufficient. For commercial and industrial applications, reinforced concrete kerbs or steel channels anchored into the sub-base are required. Edge restraints should be installed before the paving blocks are laid, with the top of the restraint set at the final paving level minus the block thickness. The blocks should butt firmly against the restraint with no gap larger than 5mm.
Joint Filling
Filling the joints between paving blocks is a critical step that locks the blocks together and provides the structural integrity of the paved surface. After all blocks are laid and compacted with a plate vibrator, spread dry, clean kiln-dried sand or fine stone dust over the entire surface. Brush the sand into the joints using a stiff broom, working it in thoroughly to ensure all gaps are completely filled. Make multiple passes in different directions to work the sand deep into the joints. After the initial filling, compact the surface again with the plate vibrator to settle the blocks further and draw more sand into the joints. Repeat the sand application and compaction process until all joints are completely full and no further sand can be worked in. Finally, sweep off any excess sand from the surface. Proper joint filling prevents weed growth, resists insect infestation, and locks the blocks together to distribute loads across the entire paved area.
Sealing And Maintenance
Sealing paving blocks is optional but recommended for certain applications to enhance colour, provide stain resistance and simplify cleaning. Sealants are available in various finishes including gloss, satin and natural matte, and can enhance the colour of the blocks while providing a protective barrier against oil, grease and other stains. Sealing is particularly recommended for driveways and commercial areas where oil leaks from vehicles are common. However, sealed surfaces can become slippery when wet, so non-slip sealants should be specified for pedestrian areas. Routine maintenance of paved areas involves regular sweeping to remove debris, occasional washing with a pressure washer to remove dirt and algae, and periodic replenishment of joint sand as it settles over time. Individual damaged blocks can be lifted and replaced without affecting the surrounding pavement, which is one of the key advantages of block paving over monolithic surfaces. With proper installation and maintenance, a Tanzibaba paved surface will provide decades of reliable service in any application.
Common Installation Mistakes
Several common mistakes can compromise the quality and longevity of a paving installation, and being aware of them helps ensure a successful project. The most common mistake is inadequate base preparation — insufficient sub-base depth or poor compaction leads to settlement and uneven surfaces over time. Using the wrong type of sand for the bedding layer is another frequent error — soft building sand should not be used as it retains moisture and can cause blocks to sink unevenly. Failing to install proper edge restraints is a critical mistake that allows blocks to spread and the surface to fail. Insufficient joint filling leaves gaps that allow weed growth and reduce the structural integrity of the pavement. Installing paving blocks directly on a concrete base without a proper bedding layer prevents drainage and can cause blocks to crack under traffic. Finally, failing to compact the blocks adequately after installation leaves them poorly seated and prone to movement. Avoiding these mistakes with proper planning and execution will ensure your paving project delivers lasting results.
Frequently Asked Questions
How do you prepare the base for paving?
Excavate to the required depth, compact the sub-grade, install geotextile membrane if needed, add and compact the sub-base material in layers, then spread and screed a 40-50mm bedding layer of sharp sand. Proper base preparation is essential for preventing settlement and ensuring long-term durability.
Do paving blocks need mortar?
No, paving blocks are laid dry on a sand bedding layer and locked together through their interlocking shape and the sand-filled joints. Mortar is not used in standard paving installations. The blocks are compacted into the bedding layer and the joints are filled with dry sand to create a flexible, permeable pavement.
How long does paving installation take?
Installation time depends on the area size and complexity. A standard residential driveway of 40-60 square metres typically takes 3 to 5 days including base preparation, laying and finishing. Larger commercial areas take proportionally longer depending on the site conditions and pattern complexity.
What is the best base for paving blocks?
The best base for paving blocks is a compacted sub-base of hard crushed stone or quarry waste, typically 150-200mm thick for residential use and thicker for commercial applications. This provides a stable, well-drained foundation that supports traffic loads without settling.
Do I need to seal paving blocks?
Sealing is optional but recommended for driveways and commercial areas where oil stains are a concern. Sealants enhance colour, provide stain resistance and make cleaning easier. However, sealed surfaces may be more slippery when wet, so non-slip sealants should be used for pedestrian areas.
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