Short answer
Clean block paving by sweeping off loose debris, pulling weeds from the joints, scrubbing the surface with water and a suitable paving cleaner, then rinsing. You can pressure wash block paving, but keep the jet moving, angled across the blocks and well back from the surface, because a close, direct jet strips the sand out of the joints. Plan to top the joints up with kiln-dried sand once everything is dry.
Before you start
Pick a dry spell with a settled forecast. The blocks need to dry out afterwards so the joints can be re-sanded properly, and you do not want rain washing loose sand away halfway through the job.
Move cars, bins and plant pots off the area and look closely at the surface. Note any blocks that rock or have sunk, joints that are already empty, and patches of oil or rust. Cleaning will not fix a problem with the base underneath, and it helps to know where the weak spots are before water goes anywhere near them.
Check where the water will run. Make sure drains and gullies are clear, and that dirty water will not flow onto a neighbour's drive or into a flower bed you care about.
What you will need
A stiff yard broom, a weeding knife or old kitchen knife for the joints, a bucket, a paving cleaner suitable for concrete blocks, and a garden hose. A pressure washer is optional. If you use one, a rotary surface cleaner attachment gives a far more even result than a bare lance, because it holds the jet at a fixed distance from the blocks.
Wear sturdy footwear, gloves and eye protection, particularly if you are using a cleaning product or a pressure washer.
Step by step
- Sweep the whole area thoroughly to remove leaves, grit and loose dirt.
- Rake weeds and moss out of the joints with the weeding knife. Our guide to weeds and moss in block paving covers this step in more detail.
- Test your cleaning product on a small, out-of-the-way block and check it does not discolour the surface.
- Wet the paving, then apply the cleaner following the manufacturer's dilution and contact-time instructions. Never mix different cleaning products.
- Scrub with the stiff broom, working in manageable sections so the product does not dry on.
- Rinse with plenty of clean water from a hose, or with a pressure washer used as described below.
- Let the paving dry completely, then brush kiln-dried sand back into the joints.
Can you pressure wash block paving?
Yes, but how you do it matters more than the machine. Block paving relies on the sand in its joints to lock the blocks together. A narrow jet held close to the surface, or pointed straight down into a joint, blasts that sand out in seconds. Once enough has gone, blocks can start to move and weeds have more room to grow.
Keep the lance moving, hold it well back and angle the spray across the blocks rather than into the gaps. Start on a lower setting and only increase it if the dirt is not shifting. Older or worn blocks deserve extra care, as too much pressure can scour the face and leave the aggregate showing.
Whichever method you use, some sand will be lost. That is normal, and it is why cleaning and re-sanding are best treated as one job. Our guide to re-sanding block paving explains how to do the second half.
Stains that need extra attention
Oil drips, rust marks and tyre scuffs rarely come out with general cleaning alone. Treat them before the main wash; our guide to removing oil stains from a driveway walks through the options. Be realistic, because some marks lighten rather than disappear, particularly if they have been there a long time.
Once the paving is clean and re-sanded, you might be thinking about a sealer. Whether that is worthwhile depends on the paving and what you want from it, which we cover in our guide on sealing block paving.
When to call a professional
It is worth calling a professional if the drive is large, heavily stained or badly overgrown, if blocks are already loose, or if you are not comfortable using a pressure washer near the joints. A good professional clean treats the surface and the joints together.
When we clean block paving, we use rotary surface cleaners for an even finish, clear the joints of weeds and moss, and re-fill them with kiln-dried sand. Sealing can be discussed on site if you want it, and a biocide treatment can be added where green growth keeps coming back. Sunken blocks or a failed base are a job for a paving contractor rather than a cleaner.
Rather have it done for you?
Block paving jet washed, weeds and moss cleared from the joints, with re-sanding discussed on site. Family-run by Jason and Lucas Prior, covering south Essex.
Frequently asked questions
Will pressure washing damage block paving?
It can if the jet is too close, too narrow or aimed into the joints, because it strips out the sand that holds the blocks in place. Used carefully, at a sensible distance and angle, it is an effective way to clean the surface.
Do I need to re-sand after cleaning block paving?
Usually, yes. Any wet cleaning loses some joint sand, and pressure washing loses more. Brushing kiln-dried sand back in once the paving is completely dry keeps the blocks locked together.
Can I clean block paving with washing-up liquid?
For light dirt, warm water with a little mild detergent and a stiff brush can help. For green growth or heavier grime, a cleaner made for paving usually works better. Rinse well either way.
Related guides
- Re-sanding block paving after cleaning: why the joints need refilling after a clean, why kiln-dried sand is used and how to brush it in so it stays put.
- Should you seal block paving?: an honest look at what a sealer can and cannot do, how to prepare for it and when sealing is better left alone.
- How to remove weeds and moss from block paving: why weeds and moss take hold in the joints, how to get them out roots and all, and how to slow them coming back.