How to Calculate Block Paving
A well-laid block paved driveway is incredibly durable and adds massive curb appeal to a property. Because block paving relies on hundreds of small bricks locking together via friction, precision in calculating both your blocks and your jointing sand is paramount.
The 50 Blocks per Square Metre Rule
The vast majority of block paving driveways in the UK are constructed using the standard 200mm x 100mm block. Because of this uniform size, there are exactly 50 blocks in every square metre (1m²) of paving, regardless of the pattern you lay them in (herringbone, basketweave, or stretcher bond).
Why Wastage Allowance is Crucial
Unlike large paving slabs, block paving often requires a lot of cutting, especially around the edges to maintain a soldier course (the border), or around manhole covers.
- Standard Shapes: For a simple, square driveway, a 5% waste allowance is typically sufficient.
- Complex Drives: If your driveway curves, tapers, or involves sweeping arcs, you will generate significantly more offcuts that cannot be reused. In these scenarios, a 10% allowance is strongly recommended.
Calculating Kiln-Dried Sand
Instead of cement, block paving relies entirely on perfectly dry, fine sand brushed down into the joints. This creates friction that locks the driveway into a solid, immovable surface. A single 25kg bag of kiln-dried sand will typically brush in and cover between 3m² and 5m² of standard 50mm thick blocks.