One of the biggest advantages of composite decking is how little maintenance it needs compared to timber. There’s no oiling, no staining, no sealing, and no sanding — ever. But ‘low maintenance’ doesn’t mean ‘no maintenance.’ A small amount of regular care keeps your composite deck looking its best for decades.
This guide covers everything you need to know about maintaining composite decking in Australian conditions — from routine cleaning schedules to dealing with specific stains, pressure washing safely, and seasonal care tips for different climates across the country.
What Is Composite Decking? — Complete Guide →
What You Don’t Need to Do
Before getting into what maintenance composite decking does need, it’s worth understanding what you can permanently cross off your list. Unlike timber decking, composite never needs oiling or staining, sealing or waterproofing, sanding, painting, or termite treatment. For a typical 30m² timber deck, these tasks cost $300–$800 per year in materials and labour. Over 20 years, that’s $6,000–$16,000 in maintenance costs that composite decking eliminates entirely.
Composite vs Timber Decking — Full Comparison →
Routine Cleaning Schedule
Regular cleaning is the single most important thing you can do to keep your composite deck in top condition. How often depends on your environment, but here’s a practical guide:
Weekly: Quick Sweep
Sweep or blow leaves, dirt, and debris off your deck regularly. This is especially important in autumn when leaf litter builds up, and in areas with overhanging trees. Organic debris left sitting on composite decking can cause surface staining over time, particularly from tannin-rich leaves like eucalyptus and oak.
Pay particular attention to the gaps between boards. Debris that accumulates in board gaps can restrict drainage and trap moisture against the subframe. A stiff-bristled broom or leaf blower makes quick work of this.
Monthly: Spot Clean High-Traffic Areas
Areas that get the most foot traffic — around doorways, BBQ zones, and outdoor dining areas — benefit from a monthly spot clean. Use warm water with a mild household detergent (dish soap works well) and a soft-bristled brush. Scrub in the direction of the board grain, then rinse thoroughly with a garden hose.
Quarterly: Full Deck Wash
Every three to four months, give your entire deck a thorough clean. This is particularly important after summer (when UV exposure and foot traffic peak) and after autumn (when leaf debris has been heaviest). The process is straightforward: clear all furniture and pot plants from the deck, sweep thoroughly to remove loose debris, mix warm water with a composite deck cleaner or mild detergent, scrub the entire surface with a soft-bristled brush working in the direction of the grain, rinse thoroughly with a garden hose, and allow to dry before replacing furniture.
Use felt pads or composite-safe feet under furniture legs before placing them back — this prevents marks from forming on the surface.
Composite Deck Cleaning and Care →
Dealing with Specific Stains
One of the advantages of capped composite decking is that most spills can be cleaned up easily if addressed promptly. Here’s how to handle common stains:
Food and Drink Spills
Red wine, coffee, juice, and BBQ sauce are the most common food stains on outdoor decks. For fresh spills, blot up excess liquid immediately (don’t rub), wash the area with warm soapy water and a soft brush, and rinse thoroughly. For dried-on food stains, soak the area with warm soapy water for 10 minutes, scrub with a soft-bristled brush in the grain direction, and rinse. Repeat if needed.
Grease and Oil
BBQ grease and cooking oil can leave marks if left to sit. For fresh grease, sprinkle an absorbent material like baking soda or cat litter on the spill to soak up the oil. Leave for 15–20 minutes, sweep up, then clean with warm soapy water. For older grease stains, use a dedicated composite deck degreaser or a solution of warm water and oxygen-based bleach. Avoid petroleum-based solvents as these can damage the cap layer.
Mould and Mildew
In humid climates — particularly Brisbane, the Gold Coast, and tropical Queensland — mould and mildew can appear on any outdoor surface, including composite decking. While capped composite is far more resistant to mould than timber, surface growth can still occur in shaded, damp areas. Clean with a solution of one part household detergents to four parts warm water, or use a commercial composite deck mould remover. Scrub with a soft brush and rinse well. To prevent recurrence, improve airflow around the affected area and trim overhanging vegetation.
Rust Stains
Rust marks from metal furniture, garden tools, or fasteners can stain composite decking. Remove the source of rust first, then treat the stain with a composite-safe rust remover or a paste of baking soda and water. For stubborn rust stains, oxalic acid-based cleaners are effective but should be tested in an inconspicuous area first.
Leaf Tannin Stains
Eucalyptus leaves, oak leaves, and other tannin-rich foliage can leave brown marks on composite decking if left sitting for extended periods. Regular sweeping prevents this, but if stains do form, they can usually be removed with warm soapy water and scrubbing. Persistent tannin stains respond well to oxygen-based bleach solutions.
Pressure Washing Composite Decking
Pressure washing is a fast way to clean a composite deck, but it needs to be done carefully to avoid damaging the surface. Follow these guidelines for safe pressure washing:
Safe Pressure Washing Settings
| Setting | Recommended | Avoid |
| Maximum pressure | Up to 1,500 PSI (10 MPa) | Above 2,000 PSI |
| Nozzle type | Fan tip (25° or 40°) | Pinpoint/zero-degree tip |
| Distance from surface | 200mm+ (8 inches) | Closer than 150mm |
| Spray direction | Along the grain | Across the grain |
| Water temperature | Cold or warm | Hot/steam |
Start with the lowest pressure setting and increase gradually until you find the minimum effective pressure for your cleaning needs. Always keep the nozzle moving — holding it in one spot can damage the cap layer. Test in an inconspicuous area first, especially if you haven’t pressure washed the deck before.
Avoid using a turbo or rotary nozzle on composite decking. These concentrated spray patterns can gouge the surface, even at lower pressure settings.
Seasonal Maintenance by Climate
Australia’s diverse climate means maintenance needs vary by region. Here’s a seasonal guide tailored to different conditions:
Sydney, Perth, Adelaide (Hot Summers, Mild Winters)
Before summer, do a full deck wash to remove winter grime before peak entertaining season. Check and tighten any loose fasteners. During summer, rinse the deck occasionally to cool the surface in extreme heat — lighter-coloured boards stay cooler. Clean BBQ grease and food spills promptly. In autumn, clear leaves frequently to prevent tannin staining. This is the ideal time for a thorough quarterly clean. During winter, check drainage points and board gaps for debris buildup. A light clean before spring is recommended.
Brisbane, Gold Coast, Tropical Queensland (Humid Subtropical)
Humidity and warmth create ideal conditions for mould growth, so proactive cleaning is especially important in these regions. Before the wet season, treat any early mould growth before humidity peaks. Ensure drainage gaps between boards are clear. During the wet season, check for mould monthly, especially in shaded areas. Clear debris more frequently as tropical vegetation drops material year-round. In the dry season, full deck wash to remove any wet-season buildup. This is the best time for a comprehensive clean. Year-round, sweep leaves and debris at least weekly. Good airflow under the deck is critical — ensure ventilation gaps haven’t been blocked.
Melbourne, Canberra, Hobart (Cool Winters, Variable Weather)
In spring, full clean after winter — check for any moss or algae growth in shaded areas. During summer, standard cleaning schedule applies. In autumn, clear leaves frequently, especially from deciduous trees. During winter, check that drainage is functioning properly. Remove any standing water or ice buildup. Ensure furniture pads are in good condition to prevent marks during wet weather.
Protecting Your Deck Long-Term
Furniture Care
Use composite-safe furniture pads or felt protectors on all furniture legs. Rubber feet can leave marks on composite surfaces. When moving heavy furniture, lift rather than drag — even premium composite can scratch under sustained dragging pressure. Consider composite-friendly furniture glides for pieces that are moved frequently.
BBQ and Fire Pit Safety
Place BBQs on a protective mat or heat shield to catch grease drips. Never place a fire pit or open flame directly on composite decking — while composite is fire-resistant, prolonged direct heat can damage the surface. Keep a minimum 300mm clearance between any heat source and the deck surface.
Pot Plants and Planters
Always use saucers under pot plants to prevent water staining and mineral buildup. Composite-safe pot feet or plant stands that allow airflow underneath are ideal. Move pots periodically to prevent permanent colour variation from UV exposure differences.
Snow and Ice (Alpine and Cold-Climate Areas)
Composite decking handles frost and cold weather well — it won’t crack or split like timber in freezing conditions. To remove snow, use a plastic shovel or broom rather than a metal shovel. For ice, use calcium chloride-based de-icer rather than rock salt, which can leave residue. Avoid chipping ice with sharp tools.
What Voids Your Warranty
Most composite decking warranties remain valid with basic care, but certain actions can void your coverage. Avoid using harsh chemical cleaners including chlorine bleach, acetone, or petroleum-based solvents. Don’t sand, paint, or stain the boards. Avoid using metal brushes or abrasive scourers. Don’t make structural modifications to the boards such as routing or planing. Improper pressure washing (too high pressure, wrong nozzle, too close) can also be grounds for warranty exclusion.
Always check your specific product warranty for a complete list of maintenance requirements and exclusions.
Composite vs Timber: Maintenance Comparison
| Maintenance Task | Composite | Timber |
| Regular cleaning | Sweep + wash 3–4x/year | Sweep + wash 3–4x/year |
| Oiling/staining | Never | Every 1–2 years |
| Sealing | Never | Every 2–3 years |
| Sanding | Never | Every 3–5 years |
| Termite treatment | Never | Annual inspection |
| Board replacement | Rare | Common (rot, splitting) |
| Annual maintenance cost (30m²) | $0–$50 | $300–$800 |
| 20-year maintenance total | $0–$1,000 | $6,000–$16,000 |
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Frequently Asked Questions
Can I use bleach to clean composite decking?
Avoid chlorine bleach (sodium hypochlorite) as it can discolour composite surfaces and may void your warranty. Oxygen-based bleach (sodium percarbonate) is a safer alternative for tough stains and mould removal. Always check your product’s care instructions for approved cleaning agents.
How often should I clean my composite deck?
A full wash every three to four months covers most situations. In humid climates (Brisbane, Gold Coast, tropical QLD), monthly checks for mould are recommended. High-traffic areas like BBQ zones and doorways benefit from monthly spot cleaning.
Will a pressure washer damage my composite decking?
Not if used correctly. Keep pressure below 1,500 PSI, use a fan-tip nozzle (25° or 40°), maintain at least 200mm distance from the surface, and spray along the grain direction. Avoid turbo nozzles and pinpoint tips.
Do I need to oil or seal composite decking?
No. Composite decking is designed to perform without any coating. Applying oil, stain, or sealant is unnecessary and can void your warranty. The cap layer on quality composite boards provides all the protection needed.
Can I use a metal brush on composite decking?
No. Metal brushes and abrasive scourers can scratch the cap layer and damage the surface. Always use soft-bristled brushes — nylon or polypropylene bristles are ideal. Standard household scrubbing brushes work well.
How do I remove scratches from composite decking?
Minor surface scratches on capped composite often fade naturally with UV exposure over a few weeks. For deeper scratches, some manufacturers offer touch-up kits. On uncapped boards, light sanding with fine-grit sandpaper can reduce scratch visibility, but this isn’t recommended for capped products as it removes the protective layer.
