How to Clean Block Paving – Driveways & Patios

Block paving is one of the most popular driveway and patio surfaces in the UK — but it comes with its own cleaning challenges. Unlike slabs, block paving relies on jointing sand to keep everything stable, and aggressive cleaning can cause more harm than good. Many people clean their blocks only to end up with loose joints, weeds returning faster, or uneven paving. This guide explains how to clean block paving properly without damaging the joints, and how to finish the job so it stays clean for longer.

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Why Block Paving Needs Different Care

Block paving is not a single surface — it’s a system. Each block is held in place by jointing sand, which fills the gaps and locks the surface together. This sand provides stability, prevents movement, and stops water from sitting under the blocks.

When joint sand is washed out, the surface becomes unstable. Blocks can shift, sink or rock underfoot. Gaps open up, rain penetrates more easily, and you get the perfect environment for weeds and moss to return even faster than before.

The joints are also where most problems begin. Seeds settle easily here, moisture is trapped, and weeds take hold quickly if the sand is disturbed. That’s why block paving often looks worse in the joints than on the surface.

Another challenge is texture. Block paving usually has a slightly rough or patterned finish that traps dirt in grooves. Even when the surface looks clean from a distance, grime can remain embedded.

This is why pressure washing alone isn’t enough — and why cleaning and re-sanding must go together for a proper result.

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How to Clean Block Paving Properly

Follow these steps to clean block paving safely and permanently:

1. Clear the area and remove existing weeds
Brush the surface thoroughly and pull any visible weeds from joints. Removing vegetation first allows treatments to reach the roots properly.

2. Apply weed killer to joints
Use a dedicated weed killer designed for hard surfaces. Target the joints rather than spraying the whole area. Allow time for it to work before moving on.

3. Apply your cleaning solution
Use warm soapy water for light dirt, or a patio cleaner designed for block paving if grime and algae are heavier. Apply evenly and allow the product to break down growth.

4. Agitate textured surfaces
Use a stiff brush to scrub grooves where dirt builds up. Focus on darker patches and high-traffic areas.

5. Rinse carefully
If pressure washing, hold the lance at a 45-degree angle across the blocks — never directly into joints. Use the lowest effective pressure to avoid washing out sand.

6. Allow to dry fully
Jointing sand must only be replaced once the paving is completely dry.

7. Re-sand the joints
Sweep in kiln-dried sand until joints are full. This is one of the most important steps. Without it, weeds, water and movement return quickly.

8. Consider sealing
Optional, but beneficial. Sealing helps lock in sand, improves colour, and makes future cleaning easier by reducing water absorption.

Patio Guard is effective on block paving. See product details.