How to Clean Composite Decking

Composite decking has become super popular with homeowners in Canada because it’s durable, low maintenance, looks great, and provides a flat-level surface. But just like any outdoor surface, it still needs regular cleaning to keep it looking its best and lasting longer. In this guide, we’ll walk you through how to clean your composite deck, the best cleaning methods, and some handy tips to make sure your deck stays in top shape all year round.

Why Regular Cleaning is Essential for Composite Decking

Composite decking is built to resist weathering, stains, and mold, but that doesn’t mean it’s totally maintenance-free. Over time, dirt, grime, and organic debris can build up, causing discolouration or even damage if left unchecked. Neglecting your composite decking can lead to the growth of algae, which usually occurs due to a mix of moisture, warmth, and limited sunlight. Regular cleaning helps:

• Keep your deck looking fresh
• Prevent mold and mildew
• Extend the life of your deck
• Maintain a safe, slip-resistant surface

With the right cleaning techniques, keeping your composite deck in good shape can be easy.

Tips To Consider Before You Start Cleaning Composite Deck

1. Always wear gloves when using any cleaning solution, as some products may irritate the skin.
2. Instead of storing leftover homemade cleaner, it’s better to dispose of it and make a fresh batch when needed.
3. Ensure that all cleaning products are kept out of children’s reach.

Tools and Supplies You’ll Need

Before starting to clean your composite deck, make sure you’ve got these tools and supplies ready:

• A soft-bristle brush or broom
• A garden hose with a spray nozzle
• Mild dish soap or a composite deck cleaner
• A bucket of warm water
• A plastic spatula (to scrape off any stubborn debris)

Optional: A pressure washer (but use it carefully!) Having everything on hand will make the cleaning process way smoother and more efficient.

Step-by-Step Guide: Best Way To Clean Composite Deck

1. Clear the Deck Surface

First things first, move any furniture, planters, or outdoor decor off the deck. Then, grab your soft-bristle broom and sweep away all the loose dirt, leaves, and debris. This step clears the surface and makes sure your deck is prepped for a deep clean!

2. Rinse the Deck

Now, grab your garden hose and give the deck a good rinse. Let the water flow steadily to wash away all the loose dirt, dust, and light debris on the surface. This step helps soften up the grime and gets the deck ready for a deeper clean. Just make sure to use a gentle stream of water—no need for high pressure, as that can push dirt deeper into the grooves, making it tougher to clean later. Take your time and make sure you hit every area evenly so that your composite deck is all set for scrubbing.

3. Prepare Deck Cleaner for Composite Decking​

Fill a bucket with warm water and add a small amount of mild dish soap or a composite deck cleaner (TimberTech has some great options). If you’re using a specialized cleaner, be sure to follow the instructions on the label for best results. Just a heads up—stay away from harsh chemicals like bleach. They can damage the deck, cause discoloration, and might even mess with your manufacturer’s warranty. This gentle cleaning method will keep your deck looking great and well-maintained without any risk of damage.

4. Scrub the Deck

To clean the composite deck, dip your soft-bristle brush into the deck cleaning solution, but make sure it’s not soaking wet. Gently scrub along the wood grain to lift off the dirt without damaging the surface. Focus on spots with stains or dirt buildup, and give those a little extra attention. If you’ve got debris stuck between the deck boards, use a plastic spatula to scrape it out gently—just be careful not to scratch the wood.

5. Rinse Thoroughly

Once you’re done scrubbing, grab the garden hose again and rinse the deck board thoroughly to wash away any leftover soap. It’s super important to get rid of all the soap residue, as any that’s left behind can attract dirt and make the deck look dull over time.

If you notice any stubborn spots while cleaning your composite deck, don’t be shy , go over them again with the scrub brush and rinse once more until the deck looks fresh and clean.

6. Dry the Deck

Make sure to let the deck dry completely before putting any furniture or decorations back. Giving it time to air dry helps prevent water spots and ensures the surface is safe to walk on. It’s key to let it dry naturally so the wood can breathe and stay in good condition. This easy step keeps your deck looking great and lasting longer, making it a safer and more enjoyable space for everyone to hang out.

Best Practices for Cleaning Composite Deck 

Here are some simple tips to keep your composite decking looking awesome:

1. Clean up spills ASAP: Even though composite decks are pretty resistant to stains, it’s still best to wipe up things like wine, grease, or food right away. This keeps any stains from setting in over time.
2. Skip the metal tools: Metal tools like steel brushes or scrapers can scratch up your deck. Stick to plastic or non-abrasive tools to keep the surface smooth and undamaged.
3. Test new cleaners first: Before using a new cleaner all over your deck, test it on a small, hidden area. That way, you’ll know it won’t mess with the colour or damage the surface.
4. Sweep regularly: Dirt, leaves, and other debris can pile up fast. Sweeping it at least once a week with the leaf blower or broom, helps prevent buildup and keeps your composite deck looking fresh all year long.

Follow these easy steps, and your deck will stay looking great for years to come!

Using a Pressure Washer: Is it Safe?

Pressure washing your composite deck gives it a fresh, clean look by removing dirt, mold, and mildew, helping it stay in great condition. (But You Have to Be Alert.) Use a pressure washer with a fan tip and set it to no more than 3100 PSI. Keep the nozzle at least 8 inches away from the deck to avoid damaging the surface.

Here’s how to use it safely:

1. Read the Manual: Before using the pressure washer, read the user manual to understand the specific instructions for your model.
2. Check for Electrical Hazards: If using an electric pressure washer, ensure the power cord is in good condition and avoid spraying water near electrical outlets or cords.
3. Wear Safety Gear: Always wear protective gear like safety glasses, gloves, and closed-toe shoes to protect yourself from debris and high-pressure water.
4. Adjust the Pressure: Use the lowest pressure setting that effectively cleans the surface, as too high a pressure can damage the composite decking.
5. Test in a Small Area: Before cleaning the entire deck, test the pressure washer on a small, inconspicuous area to ensure it won’t cause damage.
6. Keep the Nozzle Moving: Avoid focusing the water stream on one spot for too long, as it can damage the surface. Keep the nozzle moving to distribute the water evenly.
7. Work in Sections: Divide the deck into manageable sections and clean one section at a time to ensure thorough coverage.

Dealing with Stubborn Stains and Mildew

If you’ve got tough stains or mildew, here’s how to tackle them:

For Stains:

• Make a paste of baking soda and water.
• Apply it to the stain and gently scrub with a soft brush.
• Rinse well with water.

For Mildew:

• Use a composite deck cleaner made for mold and mildew.
• Apply it to the affected areas and let it sit for 10-15 minutes.
• Scrub gently and rinse thoroughly.

This should help keep your deck looking clean and fresh.

Seasonal Maintenance Tips

Your composite decking needs different care throughout the year. Here’s how to adjust your cleaning routine by season:

Spring:

• Give your deck a deep clean to remove dirt and grime from the winter months.
• Check for any damage or wear that may have occurred during the colder season.

Summer:

• Sweep regularly to get rid of pollen, dust, and other outdoor debris.
• Clean up spills right away to avoid stains from setting.

Fall:

• Clear leaves and other organic debris to prevent mold and mildew from building up.
• Do a thorough cleaning before winter hits to keep things fresh.

Winter:

• Use plastic shovel for snow removal from your composite deck.
• For ice, use a calcium chloride-based deicer instead of salt to protect the deck.

These seasonal steps will help keep your deck in top shape year-round.

How to Remove Scratches from Composite Decking

To clean or remove scratches from composite decking, try these methods:

1. Heat Treatment – Lightly heat the scratched area of your composite deck with a heat gun and gently rub it with a cloth to blend the material. Be careful not to overheat.
2. Use a Composite Repair Kit – Some manufacturers offer repair kits with wax or putty that can fill in scratches of your composite deck.
3. Buffing with Sandpaper – For deeper scratches on non-capped decking, lightly sand in the direction of the grain. Avoid this for capped composite decking.
4. Apply a Matching Color Marker or Wax Pencil – Use a deck repair marker or wax crayon to blend minor scratches with the original color.

Prevent future scratches by using furniture pads and avoiding dragging heavy objects across the composite deck.

Common Mistakes to Avoid

To keep your composite deck looking great, avoid these common missteps:

• Using abrasive cleaners: Harsh chemicals can strip away the deck’s protective coating, leaving it vulnerable.

• Overusing a pressure washer: Too much pressure can damage the surface of your deck, so use it carefully.

• Neglecting regular cleaning: If you don’t clean your deck often, dirt and mold can build up and make it harder to clean later.

• Ignoring manufacturer’s guidelines: Always stick to the care instructions specific to your deck’s brand to avoid any issues.

• Using Rubber Mats: Its best to avoid it cause discoloration due to chemical reactions with the composite deck surface, so opt for breathable, colourfast mats designed for outdoor use.

• Heavy Furniture Without Protection: Always use pads or coasters under furniture to prevent indentations or scratches on your composite deck. This will help maintain the integrity of the deck’s surface and prevent long-term damage.

• Exposing to Extreme Heat: Avoid placing hot items, like grills, directly on the deck to prevent warping. Always use a heat-resistant mat or pad underneath hot objects to protect the surface from damage.

• Ignoring Ventilation: Ensure there’s enough airflow to avoid moisture buildup. Proper ventilation helps prevent mold, mildew, and discoloration, extending the life of your composite deck.

• Weather Conditions: Avoid cleaning your composite deck in extreme weather (too hot or too cold) as it can affect how well the cleaner works and the drying process.

Conclusion: The Best Way to Clean Composite Decking

Cleaning your composite decking doesn’t have to be a hassle. By following this guide, you’ll know exactly how to clean it properly and keep it looking amazing. Just remember to use the right cleaning tools and equipment, follow seasonal maintenance tips, and steer clear of common mistakes. With regular care, your deck will stay looking fresh and beautiful for years.