Proper site preparation is essential for ensuring long-lasting and high-quality installs.
Whether working on a domestic driveway or a commercial pedestrian area, following best practices will help avoid sinking, drainage problems, or uneven surfaces.
In a recent webinar hosted by Jamie Gledhill, Engineering Technical Manager at Brett Landscaping, key aspects of site preparation were discussed, including how to align paving installations with the latest updates in BS 7533-101:2021.
Here’s our breakdown of the paving installation guide, including insights and some practical tips for installers:
Setting Out and Levels
Before any groundwork begins, accurate setting out is crucial. Establishing the correct levels ensures proper drainage and prevents water pooling. According to BS 7533-101:2021, pavement finish levels should be a minimum of 150mm below the damp-proof course (DPC) of adjacent buildings. When setting out, consider:
- Using string lines and pegs to mark out the area.
- Accounting for the recommended falls: 2.5% for coarse-textured paving and 1.25% for fine-textured paving.
- Ensuring the falls are created at the subgrade level, not within the foundation or base layers.
Excavation and Sub-Base Preparation
The longevity of a paving project relies heavily on the quality of the foundation.
- Excavation Depth: Depending on the intended traffic load, a 200-250mm depth is typically required.
- Addressing Soft Spots: Any soft areas in the ground must be removed and replaced with compacted granular material to prevent future sinking.
- Sub-Base Installation: MOT Type 1 granular material is recommended, with a minimum thickness of 150mm for driveways. Compaction is key – using a plate compactor in layers no deeper than 150mm ensures proper density.
Drainage Considerations
Effective drainage is vital for preventing surface water buildup and ensuring compliance with SuDS (Sustainable Drainage Systems). Best practices include:
- Installing a drainage fitting for every 75m² of paved area.
- Ensuring surface water travels no more than 10 linear meters before reaching a drainage point.
- Positioning soakaways at least 5m from a property and 2.5m from boundaries.
Brett Landscaping’s Permeable Flow Paving is an excellent eco-friendly solution that allows water to filter through the surface, reducing the risk of flooding and excess runoff.
Edge Restraints and Kerb Installation
Edge restraints are essential for maintaining the integrity of the paved area.
- Kerbs should be laid on a fresh concrete bed of at least 100mm thickness.
- A mortar bed (25-50mm thick) should be used for additional stability.
- Joints should be between 2-5mm and must never be butt-jointed, as wider joints risk movement over time.
Laying Course Preparation
The laying course serves as the final preparation layer before the paving blocks. For optimal results:
- Use naturally occurring sharp sand (GF85 0/4 fine aggregate) that is free-draining.
- Maintain a consistent pre-compacted thickness of 30mm.
- Avoid any binders, such as cement or bitumen, which can affect flexibility and drainage.
Block Installation and Final Compaction
Once the paving blocks are laid, proper compaction and jointing are crucial:
- A joint width of 2-5mm must be maintained to accommodate tolerances.
- Pre-compaction should be carried out before jointing sand is applied.
- Kiln-dried sand should be swept into joints, followed by final compaction to lock everything in place.
Sustainable Choices in Paving Installation
Understanding a product’s sustainability credentials is crucial in modern landscaping. All Brett Landscaping products have been awarded a 5-Star Sustainability rating, which is displayed on product pages in our literature and website. To learn more about our sustainability commitments, click here.
By following these best practices and staying current with industry standards, installers can ensure that their paving projects are durable, well-constructed, and visually appealing.
Explore Brett Landscaping’s comprehensive Installations Guides for expert insights and professional guidance.
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