Block Paving Cleaning & Sealing: The Complete Guide

The Direct Answer

How do you clean and seal block paving? A proper clean in Essex costs £150–£350 with biocide, joint resanding and low pressure. The kiln-dried sand goes back in after every clean — without it, the drive becomes loose. Sealing afterwards costs £150–£250 and stretches the next clean to 18–24 months.

Block paving is the most common driveway surface in Essex. It looks great when new and terrible when neglected — which most driveways are within a few years. This is everything you need to know about getting it right.

Why block paving goes downhill fast

Block paving has four main enemies: weeds growing between joints, black spot algae (that dark staining that looks like oil but isn't), pointing erosion from rain and traffic, and general grime accumulation. Left unchecked, these problems compound each other — weeds loosen pointing, loose pointing lets in more water, water brings more algae.

Most homeowners try to fix this with a domestic pressure washer on full power. This is the worst thing you can do.

Why you shouldn't use a domestic pressure washer

A standard consumer pressure washer running at 2,000–3,000 PSI will blast the kiln-dried sand out of every joint on your driveway. That sand is what holds the blocks in place and prevents them from shifting. Without it, blocks rock, edges lift, and the whole surface begins to degrade.

Within a year of aggressive pressure washing, most block paving driveways need re-jointing. The DIY clean ends up costing them far more than a professional one would have.

The correct cleaning process

Professional block paving cleaning follows a specific sequence:

1. Pre-treatment: Apply a specialist cleaning agent that breaks down algae, oil, and grime before any water touches the surface.
2. Low-pressure clean: Clean at controlled low pressure to remove the loosened material. Kiln-dried sand in the joints will lift during cleaning — this is expected and corrected in the next step.
3. Re-jointing: Where joints have eroded, we re-sand with kiln-dried jointing sand to restore structural integrity.
4. Biocide treatment: Apply biocide to prevent regrowth of algae, moss, and weeds for 6–12 months.
5. Sealing (optional but recommended): Apply Smart Seal to protect the finished surface.

Should you seal your driveway?

Yes, if you want it to stay clean longer and look better for longer. Sealing isn't essential but it makes a significant difference.

We use Smart Seal, which we're certified to apply. There are three finishes available:

• Natural: No colour change, just protection. Locks joints and repels water.
• Colour enhance: Deepens the existing colour of the block for a richer, fresher appearance.
• Wet look: A gloss finish that makes the driveway look freshly rained on. Popular with darker blocks.

Sealed driveways resist oil stains, repel weeds, and are far easier to clean at the next service interval. Smart Seal lasts a minimum of 3–5 years when applied correctly — 2 coats by hand roller over a fully dry, re-sanded surface.

One important rule: the driveway must be completely dry before sealing

Sealant applied to a damp surface will turn white and cloudy as it cures. We advise waiting 3–7 days after cleaning depending on weather before applying any sealant. We always check the forecast and advise accordingly — we won't seal in marginal conditions.

How often should you clean block paving?

Annually is ideal. A yearly clean prevents the buildup that requires aggressive treatment, and biocide retreatment keeps weeds and algae at bay between visits. If you've sealed, you might stretch to every two years before a full clean is needed.

FAQ: Do you always include joint resanding in the quote?

Yes — resanding is part of every block paving clean we do. The driveway needs the kiln-dried sand replaced to stay stable. If a quote doesn't mention resanding, ask before agreeing.

FAQ: Will sealing my driveway change the colour of the blocks?

Only if you choose colour enhance or wet-look finishes. Natural Smart Seal finishes preserve the original colour completely. We show samples before any work starts so you choose the look you want.