Decks are one of the most used — and most exposed — areas of any property. Whether it’s a timber deck, composite deck, poolside platform, or outdoor entertaining area, decks take a constant beating from sun, rain, foot traffic, spills, and organic growth.
Over time, this leads to:
- Slippery algae buildup
- Black mould staining
- Greyed, weathered timber
- Embedded dirt and grime
- Accelerated surface wear
Professional deck cleaning services restore the appearance of your deck, improve safety, and significantly extend its lifespan — without damaging the surface.
In this 2026 guide, we’ll cover:
- Why decks deteriorate so quickly
- Why DIY or high-pressure cleaning causes damage
- How professional deck cleaning works
- Different methods for timber vs composite decks
- How to protect your deck long-term
Why Decks Get Dirty (and Dangerous)
Decks sit at ground level and are constantly exposed to:
- Moisture and rainfall
- Shade and limited airflow
- Foot traffic and furniture movement
- Food, drink, and grease spills
- Mould, algae, and lichen growth
- UV exposure and weathering
Because timber is porous, contaminants soak in quickly. Composite decks may not rot, but they still hold grime and organic growth on the surface.
Without proper cleaning, decks become slippery, discoloured, and structurally compromised over time.
Common Deck Problems We See
Professional deck cleaning is commonly needed to address:
- Green algae growth (slip hazard)
- Black mould staining
- Grey, sun-bleached timber
- Dirt trapped between boards
- Weathered or chalky surfaces
- Preparation before staining or oiling
Left untreated, these issues can lead to rotting timber, surface cracking, and premature replacement.
Why High-Pressure Deck Cleaning Is a Mistake
One of the biggest mistakes property owners make is using high-pressure water blasting on decks.
High pressure can:
- Furry or splinter timber fibres
- Etch soft timber
- Strip stains, oils, or coatings
- Force water deep into timber
- Shorten deck lifespan
Decks require low-pressure, controlled cleaning, not brute force.
How Professional Deck Cleaning Works
At Metro Water Blasting, deck cleaning is performed using soft wash and low-pressure techniques, tailored to the deck material and condition.
Step 1: Deck Assessment
We assess:
- Deck material (timber or composite)
- Age and condition
- Level of staining or growth
- Existing coatings or oils
This determines the safest cleaning method.
Step 2: Soft Wash Treatment
A professional cleaning solution is applied to:
- Kill mould, algae, and organic growth
- Break down dirt and grime
- Lift staining from pores
This works at a chemical level, not just visually.
Step 3: Low-Pressure Rinse
The deck is gently rinsed using low pressure to remove contaminants without damaging the surface.
This preserves timber integrity and surface texture.
Step 4: Optional Brightening or Prep
Depending on the deck condition, additional steps may include:
- Timber brightening
- Neutralisation
- Preparation for staining or oiling
- Mould-inhibiting treatments
Timber Deck Cleaning vs Composite Deck Cleaning
Timber Decks
Timber decks require special care due to their porous nature.
Professional cleaning:
- Restores natural timber colour
- Removes embedded growth
- Prepares timber for staining or oiling
- Prevents rot and decay
Composite Decks
Composite decks don’t rot, but they still accumulate grime and algae.
Professional cleaning:
- Removes surface contamination
- Restores original colour
- Prevents slippery buildup
- Preserves manufacturer finish
Benefits of Professional Deck Cleaning
Deck cleaning delivers immediate and long-term benefits:
- Improves safety by removing slip hazards
- Restores appearance instantly
- Extends deck lifespan
- Reduces maintenance costs
- Enhances outdoor living spaces
- Improves property presentation
In many cases, professional cleaning adds years of usable life to a deck.
How Often Should You Clean Your Deck?
Most decks benefit from professional cleaning:
- Every 12–18 months
- Before summer entertaining
- Before staining or oiling
- When algae or mould appears
- As part of a full exterior clean
Deck cleaning is often combined with house washing, fence cleaning, or concrete cleaning for best results.
DIY vs Professional Deck Cleaning
DIY deck cleaning often results in:
- Uneven cleaning
- Timber damage
- Fast regrowth of mould
- Short-lived results
Professional services provide:
- Correct chemical balance
- Even, uniform results
- Surface-safe methods
- Longer-lasting cleanliness
Why Deck Cleaning Is a Smart Investment in 2026
Deck replacement is expensive. Cleaning is not.
Professional deck cleaning:
- Protects your investment
- Improves property value
- Enhances usability
- Prevents costly repairs
In 2026, preventative maintenance remains the smartest approach to exterior care.
Ready to Restore Your Deck?
If your deck looks weathered, slippery, or stained, professional deck cleaning can restore it safely and effectively.
Request a no-obligation quote today and let our team assess the best cleaning solution for your deck.