How to Clean a Composite Deck

How to Clean Composite Decking

Composite decks are much easier to clean than many other decking options. Solid wood decks require extensive maintenance and care, while composite materials only need a fraction of the attention.  

However, the reduced need for maintenance doesn’t mean you can leave these decks unattended. Let’s go over everything you need to know about how to clean a composite deck. 

Why Are Composite Decks Easier to Clean? 

Composite decks were made to provide homeowners with a low-maintenance option compared to traditional lumber decks. They’re made with a combination of plastic and wood, coated with a vinyl treatment. 

The amount of wood varies depending on the type of composite decking, with many products having anywhere between 40-70% wood. Antifungal chemicals and preservatives help to treat and protect wood materials from rot.  

The combination of wood and vinyl makes composite decks more durable and easier to clean than decks made from wood alone. They still need some maintenance to stay looking beautiful and inviting, but fortunately, you can clean them just by using tools you have around the house. 

Bonus: Click here to read our round-up of the best composite decking brands. 

Cleaning Tools 

Luckily, cleaning a composite deck doesn’t require any specialized tools. Odds are that you already own all the items you need to clean your composite deck properly. 

You’ll need to gather these tools from around the house: 

• Broom 
• Bucket of warm water 
• Bucket of soapy water (you can buy special composite deck cleaner or just use dish soap) 
• Deck brush (make sure the bristles are on the softer side) 
• Hose 

What Is the Best Homemade Deck Cleaner for a Composite Deck? 

If you need to know how to clean your composite decking, look no further than a DIY cleaning solution. Homemade deck cleaners are inexpensive and provide expert cleaning for both composite and wooden decking. 

Use this DIY mixture for the best eco-friendly composite decking cleaning solution: 

• One cup of white vinegar or apple cider vinegar 
• 1/4 cup of baking soda 
• One gallon of warm water 

Why is this simple solution so effective? Because the acid in the vinegar breaks down the baking soda and, in the process, releases carbon dioxide that helps remove dirt from surfaces. This DIY solution is definitely the best option if you’re looking for a quick and cheap way to clean your deck, especially since you probably already have the ingredients at home. 

To begin, simply add the vinegar to the bucket of clean water, then add the baking soda. After combining all the ingredients, you can start washing your deck. 

Importantly, do not put this solution in your power washer. It will ruin the machine because granular cleaners clog the tiny nozzles on the sprayer. 

If you don’t have the time or ingredients to create a DIY cleaning solution, the next best cleaner for composite decks is a bucket of warm water with mild soap, like Dawn dish soap. Mild dish soap or a composite deck cleaner will be as effective in cleaning your deck as a DIY solution. 

Keep in mind, if you choose a composite deck cleaner, never mix it with bleach. Mixing ammonia-based ingredients, like those in store-bought cleaners, with bleach can create toxic chloramine gas and cause respiratory irritation. Besides, most composite decking companies specify to avoid cleaning the deck with bleach because bleach is a highly toxic and corrosive cleaning solution. Although it can do wonders on tough stains, it can also wreak havoc on many materials. 

What Is the Best Deck Cleaning Brush? 

The deck brush you use is as important as the cleaning solution. The best way to clean a composite deck is with a scrub brush with soft bristles and medium stiffness. Brushes for cleaning cars with a hose attachment are usually a good option. 

A scrub brush that has too hard of bristles or that is too stiff can cause damage to your deck. You don’t want to scratch the deck when cleaning but work to loosen the dirt and grime. 

Don’t worry; soft bristles will still do the hard work of removing those stubborn stains without damaging the composite decking. Some great brushes to try are the following:  

• Comco Adjustable Handle 
• Ettor Poly Fiber Soft General Wash Brush 
• Libman 6.5 ft. Flow-Thru Wash Brush (top recommendation) 

Certain brands, like Timbertech, suggest using a natural fiber scrub brush to clean their composite decking. You can always check with your decking material company to see if they have a specific brush they recommend using for their decks. The same goes for a cleaning solution or treatment they recommend specifically for their materials. 

When in doubt, test a small area with the cleaner and brush you intend to use to check that the colors aren’t changing or that the materials aren’t damaging the Trex deck. 

You may need to get on your hands and knees with a small brush to apply more elbow grease for those extra stubborn stains. 

The Composite Deck Cleaning Process 

There are six basic steps to cleaning a composite deck. 

1. Clear your entire deck of any furniture or objects that would get in the way of the cleaning process. 
2. Use the broom to sweep the entire area and remove any leaves, debris, and excess dirt. 
3. Spread warm water over the deck to get it ready for soap. Don’t worry about wetting every single inch; just spread it out the best you can. 
4. Mix soap and warm water, similar to the ratio you might use to wash your dishes. 
5. Dip the deck brush into the bucket of soapy water and start scrubbing your deck. Don’t be afraid to apply significant pressure to clear away as much dirt as possible—composite is hardy and can take it. 
6. Once you’ve scrubbed the deck, take a hose and rinse away all the soapy water. The sun will take care of the drying part.

Should You Use the Same Methods for the Railing? 

You can use the same homemade solution or cleaner you used for the decking to clean the railings, too. Usually, soapy, warm water with a soft cloth or sponge will do the trick. Again, avoid using an abrasive brush. 

If the railings have heavy soiling, you may need to use a more powerful cleaning product, such as:  

• Alcohol 
• Diluted bleach (up to 5%) 
• Petroleum or white spirits

Never use a cleaning product with ketones or ethos. If you use a potent cleaner on the railing, rinse it off the railing immediately. 

How to Deep Clean Composite Decking 

There will likely come a time when you need to deep clean your composite decking boards. Follow the tips below to get the best results. 

Apply Cleaner 

After clearing the deck of all furniture and loose debris, you’ll want to treat your deck with a cleaning treatment like COMPO-CLEAN. Apply a thick layer of the cleaner to the surface of the deck. 

If your deck is large, applying the solution and cleaning it in smaller sections is best. 

Use a Jet Wash 

After the solution sits and soaks for about five minutes, remove it with a jet wash or pressure washer. Experts also recommend using the jet wash’s fan attachment to not compromise your deck’s finish and performance. 

When you use the jet wash, always ensure the nozzle is at least ten inches from the surface of the deck boards. If the nozzle is too close to the boards, it will damage your deck. 

Slowly clean along the length of the boards with the pressure washer to rid the deck of all the cleaning treatment. 

Pay Attention to Hard-to-Reach Spots 

Hard-to-reach spots are more likely to have stubborn dirt and debris build-up or stains, so you must apply more care to these areas. You can remove surface dirt with a sponge or continue using the jet wash. 

What NOT to Do 

Composite is popular because it’s incredibly easy to maintain and can withstand a lot. That being said, there are a few considerations to keep in mind to keep your deck looking its best.

You should avoid industrial chemical cleaners because harsh substances can eat away the composite material. Bleach is also not advisable because it can discolor the deck and ruin its appearance. 

If you are unsure if a particular cleaning solution will work for your deck, you should check the manufacturer’s recommendations. You can generally find guidelines for care on the manufacturer’s website or in the materials that came with your purchase. 

Finally, it may sound obvious, but it needs to be said; don’t clean your deck in the rain or snow. Wait for a bright and sunny day. 

How to Clean Common Problem Substances 

Decks that get a lot of traffic and exposure to the elements will typically get dirty easily. Let’s discuss some tactics for dealing with the most common sources of grime, such as how to remove stains from composite decking. 

Mold and Mildew 

Mold and mildew are not common issues for composite deck owners. Although vinyl caps help with protection, some decks still have organic wood materials at their core and are susceptible to rot.  

You can prevent mold with the soap and water cleaning routine described above. Also, keep an eye out for cracked, torn, or broken deck boards throughout the year, as moisture can seep through and cause problems. Get these repaired right away.  

Beverage and Food Stains 

You can prevent food and beverage stains with a simple dry paper towel. The plastic in the composite prevents liquids from soaking in immediately. If this technique doesn’t do the trick, the soap and water method can finish the job.  

If you’re struggling with stains despite thorough cleaning, check your composite manufacturer’s warranty to learn about getting a replacement. Many warranties cover stains from food and drinks. 

Grease and Oil 

Grease and oil should be blotted up as soon as possible. The longer these stains sit, the more likely they will sink in and become permanent. 

Once you’ve soaked it up, use the water and soap method to clean up any residual grease or oil. Grease-cutting dish soap will work wonders. 

Pollen 

Unfortunately, pollen tends to be a bit more stubborn to eliminate. Often, soap and water alone will not do the trick. 

You may need to resort to power washing to remove pollen thoroughly. You may also consider moving pollen-producing flowers away from the deck, as well as trimming the branches of trees that may drop pollen on the boards. 

Keep reading below to learn our tips for power washing your composite deck. 

Dirt & Debris 

Having a composite deck is a great investment for your home, but it’s important to keep it free of dirt and debris. 

By cleaning your composite deck on a regular basis, you’ll reduce the amount of time and effort needed for future cleanings. It’s quite easy to do but takes some elbow grease. 

Remove all loose dirt and debris with a broom. Then clean your deck with a bucket of warm water and dish soap. Be sure to use a soft bristle brush to remove dirt and debris. 

If you are using a more chemical-based cleaning product, be sure to wear gloves. Some homemade and chemical cleansers can cause skin irritation. Always keep cleaning solutions out of the reach of children. 

A low-maintenance routine as a renter or homeowner maintaining a composite deck includes the following: 

• Sweep 
• Pour or spray warm soapy water 
• Use a soft bristle brush 
• Use a garden hose to rinse 
• Let the deck dry before applying any sealant 

Be sure to check with your manufacturer for the best cleaning products, sealants, and seasonal maintenance requirements. 

Issues With Concrete, Cement, Mortar, Or Stucco Dust 

Protecting your deck from dust particles from concrete, cement, mortar, or stucco is essential. Using warm water and dish soap is recommended. Put some pressure into scrubbing your deck to clear away the dust. 

Covering your composite deck before working on your construction or remodeling project will help prevent dust and the build-up of other particles.  

Hard Water Staining 

Hard water is water with high amounts of mineral deposits such as calcium and magnesium. Spray your entire deck with soapy water and scrub with a soft bristle brush. Repeat this process if necessary until the hard water stains are gone. 

If these unappealing hard water spots continue to be visible, it’s time to look into a solution. Try a water filtration that filters out the hard water before your next deck cleaning. 

Chalk Lines 

Colored chalk line discoloration tends to be permanent. As tempting as it may be to use harsh chemicals such as chlorine bleach, this is not a good idea. 

You can attempt to wash the chalk lines with soap, warm water, and a soft bristle brush. If the chalk line remains on your composite deck, it is a possibility it’s a permanent chalk line.  

Certain chalk line colors have been deemed impossible to remove, such as red. 

Check with your deck manufacturer for the best cleaning solution for chalk lines. 

Tannins From Debris 

The plant matter or debris that causes tannins can be removed. First, sweep your deck and use a water hose if you need to. Apply a brightener once your deck is dry. 

Make sure to speak with your manufacturer about the best brand and option for applying a brightener to your composite deck. Brighteners contain oxalic acid, which is known to remove tannins.  

If you notice certain debris is seasonal, have a plan to do seasonal maintenance and cleaning to prevent tannin from staining your deck. Investing in a leaf blower might be a good idea. 

Maintaining Railings 

Cleaning and inspecting your railings often can be a big help in your deck maintenance routine. Check your railings after extreme and seasonal weather to ensure your deck is safe to use. 

Cleaning your railings on your composite deck is a beautification process that only requires the following: 

• A garden hose 
• A bucket of soapy water 
• Start cleaning from the base of the railing 

Using a mild soap is best. If you notice rust stains, hard stains, or grease on your railings, repeat your cleaning process. If you continue to see the stains, check your manufacturer’s guide for the best solution. 

Seasonal cleaning will also prevent hard water stains and rust. Be prepared with a leaf blower for the fall and a plastic shovel for the winter. Spot-checking your composite deck monthly will also help maintain your deck. 

Rubber Mats 

When you first put down your welcome mat, it’s a good idea to be aware of any chemicals that could discolor or lighten the surface of your deck. Rubber-backed mats are often filled with substances that should not come into contact with your deck. 

Mats with vinyl and latex backing can also leave marks on your deck. These mats or rugs with these types of backing materials can rust or stain your composite deck.  

Be sure to read your manufacturer’s manual or contact them for more information regarding using rubber mats on your composite deck. 

To make your composite deck less slippery, consider the below options: 

• Install anti-slip tape 
• Use anti-slip coating 
• Use anti-slip strips 
• Apply waterproof coating 

Check with your manufacturer for the best brands and course of action to keep you and your family safe from slips and falls.  

Job Site Storage 

If you’re in the process of getting your composite deck built, be sure that you or the company cover any decking materials on site properly until they are installed. Dunnage bundles should be stacked properly and on a flat-level surface. 

Never store dunnage directly on the ground. For select decking, 1” x 12” and 1” x 8” products, the bundle maximum height is 12 bundles. 

There is a maximum stack height of 14 bundles of dunnage. The dunnage should line up vertically and be 8 inches from each other. The spacing should be approximately 2 ft on center. 

How to Deal with Dirt Build-Up Between the Deck Boards 

Even the best composite decks will begin to experience build-up between the boards. So, when we discuss how to clean composite decking, we must not forget these stubborn spaces. 

When you notice dirt and grime between the boards, start by using your homemade cleaner (or mild dish soap) with warm water to rinse away the grime. If dirt remains after applying this method, use a power or pressure washer. The power washer will have an easier time reaching these challenging spaces. 

Blasting away the build-up will be no problem. But remember that if you use a jet wash, keep the PSI low (under 1,500 PSI is best) to avoid damaging the deck’s surface. 

How to Deal with Ice and Snow 

You can shovel your composite deck like you would your sidewalk. However, you must also be careful when engaging in this activity.  

Using a plastic shovel will be your best bet because metal shovels with a cutting edge can easily scratch composite decks. If you want to be especially careful following light snowfalls, you could use a broom or leaf blower to remove thin layers of snow. 

If you are dealing with particularly stubborn ice, you may opt to use rock salt or calcium chloride to melt it before attempting to shovel. Rock salt is safe for use on modern composite decks, but make sure to wash or wipe it away as soon as it’s done its job. 

How Often Do Composite Decks Need Cleaning? 

There’s no hard and fast rule as to how often composite decks need cleaning. It’s more important to clean as needed to prevent stains from setting. 

In general, try to clean your composite deck twice a year to take care of dirt and debris build-up. Many homeowners give their deck a good scrub once it’s warm enough to spend time outside and at the end of the outdoor season. 

Can You Pressure Wash? 

In general, yes. However, you need to be careful not to damage your composite deck when power or pressure washing. 

Here are a few things to keep in mind if you want to go the pressure-washing route:  

• Always use a fan tip on your pressure washer. This will ensure that the water diffuses enough to not damage the deck. 
• Keep the pressure below 1,500 PSI so you don’t risk denting the boards. 
• Don’t place the nozzle of the pressure washer too close to the surface of the deck. Always try to keep at least six inches of separation to avoid damaging the outer vinyl layer. 
• Follow the grain of the deck boards as you wash. Going against the grain leads to a greater chance of dents or damage. 

Still Need Help? Contact Us! 

If you have any additional questions about how to clean your composite deck, reach out to the experienced team at Decks & Docks. Contact us today, and a deck pro can help with any concerns you have.