The Secret to a Stunning Deck: How to Clean a Composite Deck

Whether it’s sunbathing, having the family over for a barbecue, or curling up in a comfy chair reading a novel — you love spending time on your new composite deck. 

But it’s starting to look a little grimy, and you’re wondering just how to go about getting it back to its former glory. 

If your composite deck is in need of a bit of tender loving care, you’ve come to the right place. 

We’ve got the details on how to clean composite decking, including how often you should clean and the best products to use to keep your deck looking its very best. 

Table of Contents

• Are Composite Decks Easier To Clean?
• How Do You Clean Composite Decking: 8 Easy Steps
• 5 Frequently Asked Questions on How To Clean Composite Decking
• Are You Ready To Install New Composite Decking? Contact Three Rivers Custom Decks in Portland

Are Composite Decks Easier To Clean?

Composite decks are much easier to clean compared to many other decking options. While solid wood decks demand extensive maintenance, composite materials require less back breaking maintenance work and you don’t have to worry about restaining or repainting them every five years. 

That said, less maintenance doesn’t mean your composite deck can be neglected. Failing to clean your composite deck may cost you.

The Importance of Regular Cleaning for Composite Decking

Unlike traditional wood decks, composite decking is made from a blend of synthetic materials. While it’s resistant to common issues like rot, pests, and warping, it’s still susceptible to dirt, grime, and the occasional BBQ spill. 

Before you grab your deck brush and hose, let’s take a look at the common culprits:

• Weather: Rain, wind, and sun can leave behind dust, pollen, and mildew.
• Organic matter: Leaves, bird droppings, and spilled food can stain and attract pests.
• Mold and mildew: Shaded areas on your deck may foster these unwelcome growths, appearing as unsightly black or green patches.

Composite decks make outdoor living easier, requiring less maintenance than wood. But don’t mistake “less work” for “no work.” While these boards won’t splinter or warp like wood, regular cleaning is still essential to keep them looking great for years.

Plus regularly cleaning your composite deck can:

• Reduce/prevent mold and mildew
• Extend the lifespan of your deck
• Prevent staining and fading
• Keep your deck looking impressive and ready for deck season all year round

How Do You Clean Composite Decking: 8 Easy Steps

Step #1: Prep the Deck

The first thing you’ll want to do to clean composite decking is to clear off your deck. Remove: 

• Tables
• Chairs
• Rugs
• Grills
• Planters

It’s also a good idea to prepare the surrounding area by covering anything you don’t want to get cleaner on, such as nearby:

• Shrubs
• Ornamental trees/flowers
• Grass; or
• Yard ornaments 

Step #2: Pre-Rinse With a Hose

Before applying any cleaning solution, thoroughly rinse the surface with a garden hose to remove loose dirt and debris, which will help the cleaning solution work more effectively. If you prefer using a pressure washer, exercise caution. Always use a fan-tip nozzle and adhere to the manufacturer’s recommended PSI settings to prevent damage to the deck boards.

Step #3: Mix Your Cleaning Solution

Using a bucket and warm water, mix your cleaning solution. 

Depending on the type and amount of dirt and build-up on your composite decking, you may choose to use:

• Simple Green Deck and Fence Cleaner
• Dawn dish soap or another household soap
• Half a cup of apple cider or white wine vinegar with a gallon of water and a cup of baking soda (recommended by Trex)

Step #4: Use a Soft Broom or Deck Brush

Next, it’s time to start scrubbing.

In most cases, a soft broom, handheld brush, or long-handle deck brush should get the job done. However, a handheld deck brush may be your best option for hard-to-remove spots. 

Apply the cleaning solution directly onto the deck and scrub gently but thoroughly.

Be sure to brush the deck surface along the grain of the board. This ensures that all traces of dirt and debris are removed from the expansion gaps between the boards.

Step #5: Scrub Stubborn Spots First

Knock out any especially-dirty areas first. 

This includes spots of :

• Tree sap
• Caked on dirt
• Grease or oil
• Hard water deposits like lime, calcium, or silica

Check for grime that may be stuck in the grooves and around the edges of your deck, and be ready to put in a little elbow grease if necessary. We recommend using a scrub brush.

 

Step #6: Get Rid of Mold and Mildew

Next, you will want to tackle any mold or mildew on your composite decking. 

These must be cleaned using a specialty cleaner that kills the spores and prevents the growth of additional mold.

Instead of using harmful bleach-based products to remove mold and mildew from your composite decking, simply open your pantry and grab two common household items: baking soda and vinegar.

When combined and diluted with water, baking soda (an alkaline that changes the pH of surfaces) and vinegar (an acid that kills up to 82% of all mold species) can be safely removed and eliminated by using a scrub brush. 

Try using one part vinegar, one part baking soda, and two parts water in a spray bottle to get to work on the mold. Then, rinse extra thoroughly once you’re done to remove any excess cleaner.

Do you have stubborn mold on your decking that just won’t quit? It may be time for a new deck or to call the professionals.

Three Rivers Custom Decks would love to help you restore your old deck or plan your new one. With years and years of experience building decks in the Greater Portland area, we know what we’re talking about. We can help you find the best solution for all of your decking needs. Don’t spend another deck season without a deck, or worse, with one that is structurally unsuitable for use. 

Contact the preferred composite decking experts in the area today.  

Step #7: Spray Entire Deck With Water

You’ve gotten rid of the stubborn spots, dirt, grime, mold, and mildew. 

The next step in getting your composite decking sparkling clean is wetting the entire deck in preparation for scrubbing the full areas with soap.

Step #8: Clean and Rinse the Deck

Using your pre-mixed solution, begin to clean your deck. 

If the day is sunny and hot, just do a small area to avoid the solution drying as you go. Otherwise, you can cover the entire deck with a cleaner and scrub away.

Don’t forget the final rinse!

5 Frequently Asked Question on How To Clean Composite Decking

#1: How Often Should You Clean Your Composite Deck?

If you’re serious about keeping composite decking clean, you’ll want to remove dirt and stains as they appear. 

Are you watering your newly planted flowers and accidentally splashing dirt onto your deck? Wash it off right then and there.

You move a chair and notice water deposits underneath. Clean them right away.

Are you rearranging the flower pots and notice mold growing underneath them? Treat it now so it doesn’t become a bigger problem that’s harder to clean down the road.

If you keep up with dirt as it appears, you should be able to keep composite decking looking its best by cleaning it once in the spring and once in the fall, with a bit of spot cleaning during the summer. If not, you will want to wash it down once a month. 

#2: What Is the Best Thing To Clean Composite Decking With?

At Three Rivers Custom Decks, we recommend Simple Green Deck and Fence Cleaner. You can use a soap product, such as Dawn dish soap, or a natural cleaning solution, like vinegar, water, and baking soda, but you might not get the same results as you would with Simple Green.

 

#3: Can You Power Wash Composite Decking?

Yes. 

A power washer can be the perfect solution for cleaning composite decking if you have waited too long between cleanings and have a dirty buildup or a lot of tree sap or other hard-to-remove dirt.

But proceed with caution if you decide to pull out the power washer. If it is not used properly, the high water pressure can cause irreparable damage to your composite decking.

To powerwash your composite decking, follow these guidelines: 

1. Use a pressure washer with under 3100 psi that has a fan tip attachment and a soap dispenser filled with warm, soapy water.
2. Hold the fan tip no closer than 8-in from the surface of your composite decking. 
3. Spray each board with soap, moving in broad, sweeping motions that follow the grain of the board.
4. Gently scrub each deck board with a soft bristle brush.
5. Rinse thoroughly before moving on to the next board. If you allow dirty water to dry, a grimy film will remain on the decking surface.

#4: What Should You Not Use on a Composite Deck?

When cleaning composite decking, you NEVER want to use:

• Bleach
• Grease removers 
• Other chemical products

These can damage the surface of your composite decking, break down the UV inhibitors, and cause it to bleach out over time. 

#5: What Other Preventive Care Measures Can You Take To Keep Your Compose Deck Pristine?

To keep your composite deck looking beautiful and functioning like a dream, you can follow these simple preventative tips:

• Minimize abrasion: To prevent scratches, avoid dragging furniture across the deck. Always lift and move items instead. It might require a little more muscle power, but it’ll save you a lot of work in the long run.
• Reduce dirt buildup: Place mats at entry points, like the bottom of your deck stairs, to help reduce the amount of dirt tracked onto the deck. 
• Sweep regularly: Sweep often to keep the deck surface clean and prevent dirt and debris from accumulating. Mold spores like nothing more than a nice, wet pile of leaves to call home.
• Gentle rinse: A light rinse with a garden hose and spray nozzle is usually enough to remove surface dirt and grime, keeping your deck looking fresh without much effort.

Are You Ready To Install New Composite Decking? Contact Three Rivers Custom Decks in Portland

Is it time to install a new composite deck? 

If so, the professionals at Three Rivers Custom Decks can help. 

With our combined experience of over 25 years, we’re experts in creating beautiful, easily maintained, one-of-a-kind living spaces.

We also now carry Trex decking — a sustainable decking material perfect for those who are looking for the longevity and durability of composite decking but have concerns about the environment. As opposed to traditional composite decking, Trex decking is made of 95% of recycled materials and it looks great!

Three Rivers Custom Decks would love to help you get started on building your dream deck. Give us a call to schedule your no-obligation consultation today.