How to Maintain Composite Decking with Soap and Care Tips

Dish soap can be part of a gentle clean, not a shortcut to a treatment-heavy routine. To understand how to maintain composite decking, wash it every 12 to 18 months, or more often in high-use areas, using warm soapy water and a soft brush along the board grain. Rinse the surface thoroughly and avoid pressure washing, which can damage or remove the finish.

Composite boards don’t need the annual sanding, oiling or staining used on some timber decks. They do need regular sweeping and prompt cleaning of spills, dirt and moisture, especially beneath furniture and pots where debris can collect.

This guide explains how to clean composite decking with dish soap, how often to wash it, and how to reduce the risk of scratches and stains. You’ll also learn which treatments and tools to avoid, so routine care stays simple and doesn’t damage the boards.

Recommended cleaning frequency

Knowing how to maintain composite decking starts with a simple routine: sweep away loose debris, wash with warm soapy water and a soft brush, then rinse with clean water. Work in manageable sections along the board grain and let the deck dry naturally.

1. Set a washing routine. Wash composite decking every 12 to 18 months, or more often in high-use areas. Local conditions affect how quickly dirt builds up. A deck exposed to weather, nearby trees or regular foot traffic may need cleaning sooner than a sheltered, lightly used space.
2. Sweep between washes. Remove dirt and debris whenever it gathers, rather than leaving it until the next full wash. Regular sweeping helps prevent grit from being walked across the surface. Check corners and board ends, where leaves can collect after windy weather.
3. Choose a cleaner for the material. Warm water with mild dish soap suits routine composite-deck cleaning. Timber boards may have different finishes and care requirements, so don’t assume a cleaner or treatment intended for timber is suitable for composite. If you’re learning how to maintain composite decking, keep the cleaning method gentle and material-specific.
4. Select a suitable brush. Use a soft or medium-bristle brush to lift ordinary dirt without scraping the surface. Avoid wire brushes, metal tools and abrasive pads. A brush that works on a rough timber surface may be too harsh for composite boards and could scratch their finish.
5. Prepare the area. Move outdoor furniture and store it safely before washing. Sweep first, including beneath pots and chair legs, where dirt and moisture can collect. Clearing loose grit before scrubbing reduces the chance of dragging it across the boards.
6. Clean in small sections. Apply warm soapy water to one manageable area, scrub gently and rinse before moving on. This approach helps stop cleaner drying on the surface. It also makes it easier to spot remaining dirt without repeatedly wetting already-clean boards.
7. Brush along the grain. Follow each board’s length with even strokes. If a patch remains dirty, re-wet it and repeat a light pass instead of scrubbing across the boards. This keeps the cleaning action controlled and helps avoid unnecessary surface marks.
8. Rinse and finish carefully. Rinse each section thoroughly with clean water, then let it dry naturally. Avoid pressure washing, which can damage or remove the boards’ finish. Harsh chemicals and abrasive cleaners can also harm the surface unless the decking manufacturer specifically recommends them.

Do composite decks need to be stained or oiled?

No. Composite decking doesn’t need annual sanding, stripping, painting or oiling, but leaves, dirt and moisture still need regular attention. Sweep away debris and clean spills or mould before they settle on the surface.

1. Sweep boards regularly. Remove leaves, dirt and debris whenever they build up, rather than letting them sit through wet weather. Sweep along the boards and clear corners where leaves can collect. Regular removal helps prevent dirt and moisture from remaining on the surface for long periods.
2. Clear beneath pots and furniture. Move outdoor furniture before cleaning, then sweep under chair legs and plant pots. Dirt and trapped moisture can accumulate in these sheltered spots, creating conditions where mould and mildew may develop. Keep gaps between boards clear so water can drain properly.
3. Check and prepare the surface. Look over the deck for food scraps, leaf marks, grime and damp patches. Remove loose material with a broom before washing, so grit isn’t rubbed across the boards. Clean a section with warm soapy water and a soft brush, then rinse it thoroughly with clean water.
4. Clean spills promptly. Food, oil and wine can stain composite boards if left sitting. Blot or lift away the spill, then wash the affected area with warm soapy water. Rinse thoroughly. For oil-based marks, such as barbecue splatter or sunscreen, a household degreaser may help; use it carefully and rinse the area well.
5. Treat mould or mildew carefully. Moisture and dirt left on the deck for long periods can allow mould or mildew to develop. Start by cleaning the affected spot with soapy water and a soft brush. A very diluted bleach solution may be used for a stubborn mould spot, but keep it off surrounding boards and rinse it away completely.
6. Repeat cleaning only where needed. After rinsing, inspect the boards in natural light. If dirt or a stain remains, repeat the cleaning process on that section rather than applying a coating across the whole deck. Let the rinsed surface dry naturally, then check beneath pots and furniture for remaining debris.
7. Skip timber-style surface treatments. Composite boards don’t need annual oiling or sanding to maintain them. Avoid paint and staining products, which can affect the surface and may void the warranty. If you’re planning a new or replacement deck, composite decking projects can be considered alongside the care requirements of the finished surface.

Can You Use Dish Soap To Clean Composite Decking?

Yes. Mild dish soap mixed with warm water is suitable for routine composite decking cleaning. Apply it with a soft brush, then rinse the boards thoroughly with clean water.

Composite decking warranties in Australia can have different care requirements. Follow the instructions for your specific product, and avoid paint or stain, which can void its warranty.

For a deck near a pool or the coast, wash with warm soapy water and a soft brush, then rinse thoroughly. Sweep away leaves and debris, keep board gaps clear for drainage, and avoid pressure washing or concentrated bleach.

1. Clear the surface first. Move outdoor furniture and sweep away grit, leaves and loose dirt. Grit trapped beneath a brush can scratch boards during washing. Check corners and the spaces around furniture legs, where debris can remain after the main surface looks clean.
2. Mix a mild soapy solution. Add a small amount of dish soap to warm water. Keep the mixture simple: concentrated cleaners, abrasive products and bleach-based cleaners can harm the surface unless the decking manufacturer specifically recommends them.
3. Use a soft brush. Dip the brush in the soapy water and scrub gently along the board grain. A soft or medium-bristle brush can lift ordinary grime without the harsh contact of a coarse or wire brush. Clean a small section at a time.
4. Rinse each section thoroughly. Use clean water to wash away soap and loosened dirt before moving on. Leftover cleaner can dry on the boards, so rinse carefully, including the edges and gaps where suds or debris might collect.
5. Keep the pressure washer away. Pressure washing can damage or remove the boards’ finish. A garden hose and soft brush provide a gentler way to rinse and scrub; don’t direct concentrated water pressure at the surface or board edges.
6. Repeat only where marks remain. If a dirty patch persists after rinsing, apply soapy water and brush that section again. For oil-based stains, such as barbecue splatter or sunscreen, a household degreaser may help. Rinse the treated area thoroughly afterwards.
7. Let the deck dry naturally. After the final rinse, leave the boards to dry without applying oil, paint or stain. Around pools and in coastal settings, regular sweeping and prompt removal of debris help prevent dirt and moisture from lingering between cleaning sessions.

Brush direction and avoiding surface scratches

To reduce the risk of scratches, brush along the board grain with a soft or medium-bristle brush. If the deck has been in direct sunlight, let the surface cool before cleaning. This routine does not prevent fading.

Brush along the deck surface

1. Follow the board grain. Move the brush lengthwise along each board, rather than scrubbing across it. This follows the surface direction and helps limit marks from brushing. Use steady strokes over the full dirty area, including the board edges, instead of concentrating pressure on one spot.
2. Check the brush path as you go. Look for grit caught in the bristles, particularly after brushing near leaves or built-up dirt. Lift the brush and remove trapped debris before continuing. Grit dragged across the finish can scratch it, even when the brush itself is soft.
3. Keep pressure even. Press only firmly enough to loosen dirt. If a mark remains, re-wet the area and repeat a light pass along the grain. Avoid vigorous back-and-forth scrubbing, which can scuff the surface without lifting the dirt more effectively.

Scrub with a soft or medium-bristle brush

1. Choose bristles suited to composite. A soft or medium-bristle brush can gently scrub everyday grime. Don’t use a wire brush, coarse brush, metal scraper or abrasive pad. These tools can scratch or damage the finish, even if they’re useful for tougher jobs on other materials.
2. Use a firmer brush only with care. For a stubborn stain, work lightly with a firmer brush, following the board grain. Stop if the surface starts to look scuffed. A harder brush should loosen the mark, not scrape the composite itself or alter the board’s colour.
3. Rinse between passes. Rinse the brush and the scrubbed area with clean water to remove loosened dirt. This prevents debris from accumulating in the bristles and being rubbed back over the surface. Once the boards are clean, rinse them thoroughly and allow them to dry naturally.
4. Clean only after the boards cool. If prolonged sunlight has left the deck hot, wait for the surface to cool before brushing or rinsing. This is a practical part of cleaning in strong Australian sun. Don’t use sanding to tackle a mark; composite decking needs basic cleaning, not timber-style sanding.
5. Keep the finish in mind. A careful brush routine removes grime without treating the boards like timber. Use gentle, grain-following strokes, then inspect the cleaned area before repeating. If dirt remains, re-wet and scrub lightly rather than increasing pressure or reaching for a harsher tool.

Avoiding paint, stain and concentrated bleach

Composite boards need cleaning, not timber-style coatings. Avoid treatments and cleaning products that could damage the surface or affect the product warranty.

1. Keep paint and stain off the boards. Composite decking doesn’t need painting or staining as part of routine care. These products can alter the finish, and paint or staining products may void the warranty. Don’t apply leftover timber stain just because nearby timber furniture or screening needs treatment.
2. Protect the deck during nearby painting. If you’re painting a fence or outdoor structure, keep splashes off the decking boards. Move furniture away from the work area and use a protective covering, securing it so wind won’t drag it across the surface and cause a scratch. Remove the covering when the work is done.
3. Avoid concentrated chlorine bleach. Concentrated bleach can wear down the composite surface. Don’t pour it directly onto boards or use it as a general cleaning product. If mould is the concern, start with routine cleaning and use only a treatment specifically recommended for the decking material.
4. Read the cleaner label before use. Avoid harsh chemicals, abrasive cleaners and bleach-based products unless the manufacturer recommends them for your boards. Check the product’s intended use and warnings, not just its general cleaning claims. A product suited to a concrete path or timber surface may not suit composite decking.
5. Deal with spills without coating the deck. Food, oil and wine can leave marks if left sitting. Remove spills promptly, then clean the affected area with warm soapy water. For oil-based marks, such as barbecue splatter, a household degreaser may help. Rinse thoroughly after cleaning.
6. Consider weather and surface temperature. After prolonged Australian sun, let hot boards cool before cleaning. A cleaning product can dry quickly on a warm surface, leaving residue that needs another rinse. Choose a cooler part of the day and clean manageable sections, rather than applying cleaner across the entire deck.
7. Don’t try to restore colour with sanding. Composite decking doesn’t require annual sanding, stripping, painting or oiling. Abrasive sanding can damage its finish instead of providing a proper restoration. For ordinary dirt, use basic cleaning; if a mark remains, repeat the suitable cleaning process on that section.
8. Plan changes around the deck carefully. If weathering or surface marks have you considering a replacement, discuss your deck plans before applying a coating. A fresh surface may suit the space better than an unsuitable treatment, while careful product choices help protect the existing boards.

DreCo: Decking & Deck Construction

DreCo can help when routine cleaning isn’t enough and you’re considering a new deck or a replacement. Its Decking & Deck Construction and Composite Decking services are relevant if you’re planning a composite surface for your outdoor space. For a timber deck that needs replacing, DreCo also offers Timber Decking & Re Decking.

If your project also includes the boundary, DreCo’s Fencing, Gates & Privacy Screens can complement the outdoor carpentry work. Whether you’re comparing composite with timber or already know what you want, contact DreCo to discuss the decking work for your project.

Plan the next step for your outdoor space

Knowing how to maintain composite decking helps you decide what your outdoor space may need next. If you’re planning a new layout, replacing a deck or changing materials, consider how you use the area day to day. That can guide how the deck connects with the rest of the yard and which finish suits your home.

DreCo offers Decking & Deck Construction and Composite Decking, as well as Timber Decking & Re Decking. Those options provide a practical starting point if you’re weighing up a new composite surface against a timber deck or planning a replacement. You can bring an early idea or a clear plan and discuss the decking work that fits your home.

Contact DreCo about your decking to talk through your project. A considered next step can help you shape an outdoor space that works well for your household.

Frequently Asked Questions

Why Are Composite Decks Easier To Clean?

Composite decks need surface cleaning rather than annual sanding, stripping, painting or oiling. Routine care is therefore simpler than maintaining timber that needs periodic coating. When considering how to maintain composite decking, check for dirt around furniture, pots and board edges. Sheltered spots can trap debris and moisture, even when exposed boards look clean.

Can You Power Wash Composite Decking?

No. Avoid power washing composite decking because the force can damage or remove the boards’ finish, even after wet or windy weather. Scrub with a soft brush and warm soapy water, then rinse with clean water. If a patch remains dirty, repeat the gentle cleaning rather than aiming concentrated pressure at it.

Can you use a high pressure cleaner?

It’s best to clean composite boards gently rather than with forceful water jets. Pressure washing itself can damage or remove the finish, so no pressure setting is recommended. Near a doorway or garden bed, use warm soapy water and a soft brush, then rinse thoroughly with clean water. This avoids directing a forceful jet at the surface.

Why does my deck look like it’s fading?

A dull or uneven-looking deck may have dirt or cleaning residue on its surface. Clean a small area and compare it once dry. Don’t try to restore the colour with paint, stain or sanding: these can damage the composite finish, and paint or stain may void the warranty. If the appearance still differs after gentle cleaning, follow the product’s care instructions.

How often should composite decking be cleaned in Australia?

Wash composite decking every 12 to 18 months, or more often in high-use areas. Local conditions also matter: weather exposure, nearby leaves and dirt, and regular use can call for more frequent cleaning. A deck beside a busy entertaining area may collect grime faster than a lightly used space. Sweep whenever debris builds up, rather than waiting for the scheduled wash.

Which cleaners are safe for composite decking, and which should be avoided?

For routine cleaning, use warm water with mild dish soap and a soft or medium-bristle brush. Avoid harsh chemicals, abrasive cleaners and bleach-based products unless the decking manufacturer recommends them. Concentrated chlorine bleach can wear down the surface. Don’t refresh the boards with paint or stain, as these can harm the finish and may affect the warranty.

Can you use a pressure washer on composite decking, and what pressure is safe?

Avoid pressure washers on composite decking; no safe pressure setting is provided for this method. Pressure washing can damage or remove the board finish, so increasing distance or lowering the setting isn’t a reliable alternative. Use a soft brush with warm soapy water, working along the grain. Rinse with clean water and let the boards dry naturally.

How do you remove mould, mildew, grease, and stains from composite decking?

When marks appear, match the cleaning method to the stain. Clean mould, mildew and ordinary marks with warm soapy water and a soft brush, then rinse thoroughly. For a stubborn mould spot, a very diluted bleach solution may be used; keep it off surrounding boards and rinse it away completely. A household degreaser may help with oil-based marks.