Should you jet wash block paving?

Written by PureSeal Services on September 4, 2025. Posted in Blog, Pressure Washing

Block paving is one of the most popular choices for driveways, patios, and pathways. It looks attractive, adds value to a property, and, when maintained correctly, can last for decades. But like all outdoor surfaces, block paving is constantly exposed to the elements. Dirt, moss, weeds, algae, and stains build up over time, leaving it looking tired and neglected.

A common question homeowners ask is: “Should you jet wash block paving?”

The short answer is yes — jet washing can be a safe and effective way to clean block paving. However, it must be done carefully to avoid damaging the blocks or washing away the jointing sand that holds them in place. This article will explore the pros and cons of jet washing block paving, the correct method, alternatives, and tips for keeping your paving in great condition.

1. Why Block Paving Gets Dirty

Block paving is exposed to more than just dirt and rainwater. Here are the most common causes of staining and discolouration:

Moss and algae growth – thrives in damp, shaded areas.
Weeds – sprout between joints if sand becomes loose or contaminated.
Oil stains – from cars parked on driveways.
Rust stains – from metal furniture or garden tools.
General dirt and grime – carried by shoes, pets, and rainfall.

Because block paving has joints filled with sand, it is more prone to weed growth and requires specific cleaning techniques.

2. Benefits of Jet Washing Block Paving

Jet washing (or pressure washing) has many benefits when used correctly.

Restores appearance – Removes years of dirt and organic growth.
Fast and efficient – Cleans large areas quickly compared to scrubbing.
Deep cleaning – Reaches into pores of the blocks to remove stubborn stains.
Improves safety – Eliminates slippery moss and algae.
Boosts property value – Makes driveways and patios look fresh and well-maintained.

3. Risks of Jet Washing Block Paving

While jet washing is effective, improper use can cause damage.

Loss of jointing sand – High pressure can dislodge sand, destabilising the paving.
Surface etching – Holding the nozzle too close can roughen or mark block surfaces.
Water penetration – Excessive washing may force water into the sub-base.
Weed regrowth – If not re-sanded, gaps allow weeds to return faster.

So, jet washing should always be followed by re-sanding and, ideally, sealing.

4. Best Practices for Jet Washing Block Paving

To jet wash safely, follow these steps:

Step 1: Preparation

Remove furniture, cars, and pots from the area.
Sweep away loose debris.
Apply weed killer a few days before to loosen growth.

Step 2: Choose the right equipment

Use a pressure washer between 1,500–2,500 PSI.
Fit a fan nozzle (25° or 40°) instead of a pinpoint jet to spread the pressure.
Consider a rotary surface cleaner attachment for even cleaning.

Step 3: Cleaning process

Start at one corner and work systematically.
Hold the lance at least 12 inches from the surface.
Use sweeping, overlapping motions.
Avoid focusing too long on one spot.

Step 4: Rinsing

Rinse the whole surface with clean water to wash away dirt and debris.

Step 5: Re-sanding

Allow the surface to dry fully (24–48 hours).
Brush kiln-dried sand into the joints with a broom.
Compact the sand by brushing in several directions.

Step 6: Sealing (optional but recommended)

Apply a paving sealer to protect against stains, weeds, and moss.
This reduces the frequency of future cleaning.

5. How Often Should You Jet Wash Block Paving?

Annually: Once a year is enough for most homes.
Bi-annually: For shaded or damp areas prone to moss.
As needed: Spot clean oil or rust stains between deep cleans.

Over-cleaning with a pressure washer may wear down the paving faster. Balance cleaning with preventive care.

6. Alternatives to Jet Washing

If you prefer to avoid jet washing, other cleaning methods exist:

Biocides – Kill moss, algae, and weeds over time.
Scrubbing + soapy water – Good for smaller areas but more labor-intensive.
Weed burners – Kill weeds without chemicals, but don’t clean dirt.
Vacuum sweepers – Remove debris without disturbing sand.

While effective, these methods take longer and may not achieve the same instant results as jet washing.

7. DIY vs Professional Jet Washing

DIY

Lower cost (renting a jet washer £40–£80 per day).
Requires time and effort.
Risk of mistakes (e.g., uneven cleaning, sand removal).

Professional

More powerful equipment.
Skilled at avoiding damage.
Can include re-sanding and sealing.
Cost: £150–£400 depending on size.

If your block paving is heavily stained or very large, hiring professionals may be the best option.

8. Cost Considerations

DIY cleaning – £60–£150 (equipment + sand).
Professional cleaning – £150–£400.
Sealing (optional) – £200–£500 depending on surface size.

Compared to replacing block paving (£2,000–£5,000+), cleaning is highly cost-effective.

9. Common Mistakes to Avoid

Using too high pressure.
Holding the nozzle too close.
Forgetting to re-sand joints.
Jet washing in freezing or wet weather.
Using bleach or harsh chemicals.

10. Case Study Examples

Example 1: Residential driveway

3-car driveway, heavily mossed.
Jet washed in 3 hours.
Re-sanded and sealed.
Total time: 2 days including drying.

Example 2: Patio with weeds

Patio covered in weeds.
Weed killer applied one week before.
Jet washed and re-sanded.
Sealed 48 hours later.
Looks brand new.

11. Seasonal Timing for Jet Washing

Spring – Best time to remove winter grime.
Summer – Fast drying, ideal for sealing.
Autumn – Clear leaves first to avoid stains.
Winter – Avoid jet washing in freezing temperatures.

12. Environmental Considerations

Use eco-friendly detergents.
Avoid excessive water usage.
Prevent dirty water from entering storm drains.
Dispose of moss and weeds responsibly.

13. Long-Term Maintenance Tips

Sweep regularly to prevent debris build-up.
Apply biocide annually to suppress moss and algae.
Top up jointing sand when needed.
Seal the paving every 2–3 years for added protection.

14. Should You Seal Block Paving After Jet Washing?

Yes — sealing offers several advantages:

Reduces water penetration.
Prevents weeds and moss.
Protects against stains.
Enhances color and finish.
Extends the lifespan of the paving.

While sealing adds time and cost, it reduces the frequency of cleaning required.

15. Pros and Cons of Jet Washing Block Paving

Pros

Fast, effective cleaning.
Restores original look.
Increases safety.
Cost-effective maintenance.

Cons

Can damage joints if done incorrectly.
Requires re-sanding afterwards.
Overuse may shorten lifespan.

16. How Long Does It Take?

Small patio (2×2m): 1–2 hours.
Medium driveway (3–4 cars): 2–3 hours.
Large driveway (5+ cars): 4+ hours.
Add 1–2 days for drying before re-sanding and sealing.

17. Troubleshooting

Weeds return quickly – Not re-sanded properly or not sealed.
Streaky finish – Moved washer too fast; go over again evenly.
Loose blocks – Sub-base issues; may require relaying.
Stains remain – Pre-treat with specialist cleaners.

18. Comparing Jet Washing to Other Surfaces

Concrete – Jet washing is highly effective, less risk than block paving.
Tarmac – Jet washing should be gentle; too much pressure damages the surface.
Resin driveways – Usually cleaned with low pressure only.

Block paving requires the most care due to its sand-filled joints.

19. Is Jet Washing Worth It?

Yes — when done properly, jet washing:

Restores beauty.
Improves safety.
Extends lifespan.
Costs far less than replacement.

It’s an essential part of block paving maintenance.

20. Final Verdict

So, should you jet wash block paving?

Yes, but with caution. Jet washing is one of the best ways to clean block paving, provided you use the correct pressure, technique, and follow up with re-sanding (and ideally sealing).

Done right, it transforms a tired, weed-ridden driveway or patio into a surface that looks almost brand new. Done wrong, it can destabilise the paving and accelerate weed growth.

For most homeowners, jet washing once a year — followed by proper aftercare — is the perfect balance.

Final thought: Jet washing block paving is not just about cleaning — it’s about protecting your investment, boosting curb appeal, and ensuring your paving lasts for many years to come.

Tags: Driveway cleaning, Exterior cleaning, gutter cleaning, Patio cleaning, pressure washing, Roof Cleaning, window cleaning