Complete Exterior Cleaning Guide

Ideal Pressure

200 bar (3000 PSI) - full power for best results.

Best Tools

• Turbo nozzle - strong, rotating jet for deep cleaning
• Flat surface cleaner - even cleaning, no streaks

Risk of Damage Low

Block paving is tough - low risk if done correctly.

Tips

• Remove moss first - scrape or brush before applying chemicals
• Don't blast water directly into joints - can wash out sand
• Can be sealed after cleaning for longer-lasting results

Ideal Pressure

Low pressure only - tarmac is much softer than other surfaces.

Best Tools

• Flat surface cleaner only - even pressure distribution, use in a figure of 8 motion

Risk of Damage Very High

Wrong pressure or nozzle can cause etching, stripping, and surface damage.

Chemicals to Avoid

Use registered biocide only. Avoid all other chemicals.

Tips

• Check for damage before starting - repair crumbling edges first
• Can be sealed to even out colors and protect from oil stains

Ideal Pressure

Low to medium pressure - depends on resin quality and age.

Best Tools

• Flat surface cleaner - even pressure distribution, use in a figure of 8 motion
• Wide fan nozzle - gentler for delicate areas

Risk of Damage Medium

Can dislodge loose stones if pressure is too high or resin is degraded.

Tips

• Test in an inconspicuous area first
• Avoid direct high-pressure jets on edges
• Consider soft washing for older installations
• Check for loose areas before cleaning

Ideal Pressure

Medium pressure (150-180 bar) - strong enough to clean, gentle enough to preserve sealant.

Best Tools

• Flat surface cleaner - prevents streaking
• Fan nozzle - for edges and detail work

Risk of Damage Medium

Can strip sealant and fade colour if cleaned incorrectly.

Important

Must be re-sealed after cleaning - the sealant protects the colour and pattern.

Tips

• Clean in consistent, overlapping strokes
• Allow to dry completely before re-sealing
• Use quality acrylic or polyurethane sealant

Ideal Pressure

Medium pressure - concrete can be easily etched.

Best Tools

• Fan tip nozzle - a turbo nozzle would create etching
• Flat surface cleaner - faster coverage, even results

Risk of Damage Medium to High

Durable surface but susceptible to direct pressure.

Tips

• Pre-treat oil stains with degreaser
• Use sodium hypochlorite for algae and moss
• Work in sections to avoid drying lines
• Can be sealed for easier future maintenance

Same as with block paving.

The only difference is the aggregate that is brushed into the gaps between the blocks - permeable blocks have a 3mm stone where block paved has kiln dried sand.

Ideal Pressure

Medium to high pressure - granite is very hard, but joints are vulnerable.

Best Tools

• Fan nozzle - better control around joints
• Flat surface cleaner - for larger areas

Risk of Damage Medium

Stone itself is very durable, but mortar joints can be damaged by excessive pressure.

Tips

• Avoid directing pressure into joints
• Check mortar condition before starting
• May need re-pointing after cleaning
• Use biocide for organic growth

Ideal Pressure

High pressure (180-200 bar) - granite can handle full power.

Best Tools

• Turbo nozzle - excellent for stubborn stains
• Flat surface cleaner - faster, even coverage

Risk of Damage Very Low

Granite is one of the hardest natural stones - very resistant to pressure washing damage.

Chemicals to Avoid

Do not use sodium hypochlorite on granite. Granite contains iron deposits - if sodium hypochlorite comes into contact with the iron, it will cause permanent rust spots that cannot be removed.

Tips

• Pre-treat oil stains with degreaser if needed
• Mortar joints may need care - avoid excessive pressure on pointing
• Can be sealed for easier future maintenance

Ideal Pressure

Medium pressure - durable but still requires care.

Best Tools

• Flat surface cleaner - even cleaning, no streaks
• Fan jet nozzle - gentler option for rinsing

Risk of Damage Low

Low risk with proper technique, but avoid excessive pressure on softer areas.

Tips

• Apply sodium hypochlorite for stubborn biofilms
• Use a biocide to remove any black spot
• Can be sealed to protect from weathering and dirt buildup

Ideal Pressure

Medium pressure - porcelain is non-porous and very hard.

Best Tools

• Flat surface cleaner - streak-free results
• Standard nozzle - for stubborn spots

Risk of Damage Very Low

Porcelain is extremely hard and non-porous - very resistant to damage.

Tips

• Can handle most cleaning chemicals safely
• Grout lines may need extra attention
• Use biocide for algae in shaded areas
• No sealing required - porcelain is naturally non-porous

Ideal Pressure

Very low pressure only - marble is soft and highly susceptible to etching.

Best Tools

• Wide fan nozzle only - spreads pressure over larger area
• Keep nozzle at least 500mm from surface

Risk of Damage Very High

Marble etches easily and damage is permanent. Even water at wrong pressure can cause marks.

Chemicals to Avoid

Avoid ALL acids and sodium hypochlorite - will cause permanent etching and discolouration.

Tips

• Soft washing is preferred over pressure washing
• Use only pH-neutral cleaners specifically designed for marble
• Test any method in an inconspicuous area first
• Consider professional restoration if heavily soiled

Ideal Pressure

Low pressure only - limestone is a soft stone.

Risk of Damage High

Limestone can be easily etched. Once damaged, cannot be restored.

Chemicals to Avoid

Avoid sodium hypochlorite AND all acid-based cleaners - will cause permanent damage.

Tips

• Consider soft wash method instead of pressure washing
• Keep nozzle 400-500mm away from surface
• Can be sealed to protect from weathering

Ideal Pressure

Low pressure - slate is a delicate stone.

Risk of Damage High

Can easily delaminate. Sharp shards can break off if pressure is wrong.

Chemicals to Avoid

Avoid sodium hypochlorite and acid - both cause permanent damage.

Tips

• Keep nozzle 400-500mm away
• Avoid high pressure and direct angles
• Use soft washing method if possible

Ideal Pressure

Very low pressure - the polished finish can be damaged by high pressure.

Best Tools

• Wide fan nozzle - disperses pressure
• Soft brush attachment for gentle scrubbing

Risk of Damage High

Polished surfaces can lose their shine permanently if cleaned incorrectly.

Chemicals to Avoid

Avoid acids and harsh chemicals - can dull the polished finish permanently.

Tips

• Soft washing is the safest approach
• Use pH-neutral stone cleaners only
• May need professional re-polishing if finish is damaged
• Regular gentle cleaning prevents build-up that requires aggressive cleaning

Ideal Pressure

Low to medium pressure - more durable than standard tarmac but still needs care.

Best Tools

• Flat surface cleaner - even pressure distribution
• Fan nozzle - for edges and detail work

Risk of Damage Medium

More resilient than standard tarmac but the binder can still be damaged by excessive pressure.

Chemicals

Use registered biocide only for moss and algae. Avoid harsh chemicals.

Tips

• Check surface condition before cleaning - repair any damage first
• Work in a consistent pattern to avoid streaking
• SMA has better drainage than standard tarmac due to stone content
• Can be sealed after cleaning for protection

Ideal Pressure

Low pressure - wood is delicate.

Risk of Damage High

Can cause permanent streaks, splintering, or structural weakening.

Chemicals to Avoid

Never use sodium hypochlorite - breaks down melanin, causing wood to weaken and fail.

Trigger Technique (Critical)

1. Point away, pull trigger
2. Lower lance and move along full length of deck
3. Release trigger away from wood
4. Never stop mid-pass - leaves permanent lines

After Cleaning

Use specialist wood cleaner, then apply high-quality wood oil once dry.