Why Pressure Washing Is The Perfect Time To Seal Your Paving

Once a driveway or patio has been pressure washed, it's genuinely at its best: every trace of dirt, moss, algae and old grime has just been stripped away, and the surface is as clean as it's going to get. That moment is also, for a reason rooted in basic surface chemistry rather than sales technique, the ideal time to apply a sealant — because sealant can only bond properly to a surface that's clean and dry. Applying it over dirt or residual algae just traps that layer underneath the seal.

What Paving Sealant Actually Does

Sealant isn't a coating that sits invisibly on top doing nothing — it changes how the surface behaves in a few concrete ways, consistently described across manufacturer technical guidance:

• Stain and oil resistance: a sealed surface resists oil, grease and general staining penetrating into the paving, making spills easier to clean before they set in.
• Weed and moss suppression: sealant applied with a sprayer soaks down into the sand joints between blocks, hardening that sand and making it much harder for weed and moss growth to establish.
• Colour enhancement and UV protection: sealant restores some depth and richness to faded paving colour, and helps slow further fading from UV exposure.
• Joint stability: hardened, sealed sand joints are more resistant to being washed or swept out over time, which keeps the paving structurally tighter for longer.

Is It Actually Necessary?

Worth being straightforward about this: paving that's been installed correctly, on a proper sub-base with kiln-dried sand in the joints, doesn't strictly need to be sealed to function. Sealing is a recommended enhancement, not a structural requirement — reputable sources are clear on that distinction. The case for it is about extending the time between deep cleans, keeping the surface looking better for longer, and reducing how easily it stains or grows weeds — not about preventing paving failure.

A Word On The Evidence Behind This

It's worth being transparent about where this information comes from. Unlike questions such as gutter-related mould risk or roof algae biology — where independent bodies like government environmental or health agencies publish guidance — paving sealant performance is documented primarily by manufacturers and paving suppliers (Tobermore, Smartseal and others) rather than an independent regulator or scientific study. That doesn't make the claims untrue; weed suppression and stain resistance from sealed sand joints are well-established, consistently described outcomes across the industry. It's simply a different category of evidence than a government health guideline, and worth knowing the difference.

Timing and Reapplication

Sealant is typically applied after the surface has been thoroughly cleaned and allowed to dry fully — rushing this step is the most common reason a seal underperforms. Application method varies by product and contractor; a sprayer gives an even, controlled coat across the surface and works well on both open paving and sand-jointed areas. Depending on the product and the level of foot or vehicle traffic, a sealed surface generally holds up well for a few years before it's worth reapplying, at which point another clean-and-reseal cycle keeps the protection going.

Sources

• Tobermore — Block Paving Sealer FAQs, homeowner technical guidance
• Smartseal — Block Paving Sealer product and application guidance
• Independent consumer trade advice (MyJobQuote) — "Does block paving need to be sealed?"