How to Clean an Interlocking Patio (Without Damaging It)
Pressure washer settings, safe cleaners and joint-saving technique
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Cleaning an interlocking patio is mostly easy and occasionally tricky. The wrong technique can damage the joints, blow out the polymeric sand and leave you needing a $400 re-sand. Here is how to do it without that.
Annual routine (5 minutes per m²)
Sweep the patio. Use a stiff bristle broom to clear leaves, debris and surface dirt. Most years, that is 90% of the cleaning. If the surface needs a refresh, hose it off with a garden hose and let it dry. Done.
When to escalate to pressure washing
Pressure wash only when sweeping and hosing have not worked. Signs you need to: visible biological growth (green or black streaks from algae or moss), embedded surface dirt that has accumulated over multiple years, or after a heavy yard renovation that left soil tracked across the patio.
Pressure washer settings that do not destroy the joints
Three rules. Pressure: 1500 PSI maximum. Most consumer pressure washers go up to 2000-3000 PSI. Dial it down. Tip: 25-degree fan tip (often colour-coded green). Never the zero-degree pinpoint (red) on pavers; it will destroy joint sand and can pit soft pavers. Distance: hold the wand 30 cm above the surface. Closer than that and you start blasting joint sand out.
Move in a steady sweeping motion, parallel to the joints where possible, not perpendicular. Work in 1-2 m² sections, rinsing as you go.
Stains and how to treat them
| Stain type | Safe approach |
|---|---|
| Biological growth (green/black) | Oxygen bleach diluted per label, brush in, rinse. Or a paver-specific cleaner. |
| Oil and grease | Cat litter to absorb, then a degreaser made for masonry. Multiple applications often needed. |
| Rust (from outdoor furniture, BBQs) | Oxalic-acid-based rust remover labeled safe for concrete/pavers. Test in a hidden spot. |
| Efflorescence (white residue) | Often goes away on its own. Persistent cases: an efflorescence cleaner from a paver supplier. Not muriatic acid. |
| Mortar or grout splatter | Mortar dissolver from a masonry supplier. Or careful chiseling. Time-consuming. |
| Red wine, food spills | Hot soapy water and a brush within 24 hours usually does it. |
Things that will damage your patio
Muriatic acid. Eats away the cement binder in concrete pavers. Sometimes recommended for efflorescence; do not use it on pavers.
Chlorine bleach. Can discolour concrete pavers and kills any beneficial planting in adjacent garden beds.
Wire brushes. Scratch the surface texture on textured pavers. Use bristle, not wire.
De-icing salt with calcium chloride. Aggressive on concrete pavers. Use sodium chloride (rock salt) or sand for traction in winter.
Zero-degree pressure washer tip. Even at low PSI, the concentrated stream is too aggressive. Always use a fan tip.
If you blew out the joint sand: what now
Common after the first aggressive pressure wash. The fix is straightforward. Let the patio dry completely. Sweep new polymeric sand into the joints, working it down with a stiff broom until the joints are full. Mist with water to activate. The polymeric sand sets back like a fresh install. A 30 m² patio re-sand uses 2 to 3 bags of polymeric sand and takes about two hours.
Frequently asked questions
Can I use a pressure washer on an interlocking patio?
Yes, but at lower pressure than you would for concrete or siding. 1500 PSI maximum, 25-degree fan tip, 30 cm from surface. Higher pressure or closer distance blasts out joint sand.
How do I get green stuff off my pavers?
Biological growth (algae, moss) responds to oxygen bleach diluted per label or a paver-specific cleaner. Apply, brush in, let dwell 5 to 10 minutes, rinse. May need a second application for thick growth.
What is the white powder on my pavers?
Efflorescence: calcium deposits leaching out of the concrete paver as it cures. Common in the first 1 to 2 years of a new install. Usually disappears on its own with weather exposure. Persistent cases respond to efflorescence-specific cleaners.
Can I use bleach to clean pavers?
Oxygen bleach (sodium percarbonate, less aggressive) is fine and effective. Chlorine bleach can discolour pavers and damage adjacent plantings. We recommend paver-specific cleaners over either.
How often should I clean my paver patio?
Light sweep weekly during use season. Full clean (hose + maybe pressure wash) once a year, usually in spring after the snow melt. Stain spot treatments as needed. Total time investment: roughly an hour per year on a typical patio.
- Paver sealing & restoration (service)
- Interlocking patios & driveways (service)
- How long does an interlocking patio last?
Sources and further reading
- Interlocking Concrete Pavement Institute (ICPI) for paver industry standards, base-prep specifications and installer certification.
- Landscape Ontario for Ontario industry standards, member directories and consumer resources.
- Belgard, Techo-Bloc, Unilock and Permacon for paver product specifications and warranty information.
- Peace Love Landscaping installer experience across hundreds of projects in Hamilton-Wentworth, Halton and Niagara, 2008-2026.