Decks made of traditional lumber are cleaned one way, and composite, or "alternative decking," surfaces are cleaned another way. This blog will address the cleaning of a composite deck.

Most alternative decking manufacturers like TimberTech and Trex have a section on their websites about cleaning. The manufacturers' sites are always great for up-to-date information and information specific to that brand. Corte*Clean is a cleaner that works well on many brands of manufactured decking.

Corte*Clean is specifically designed for use on composite decking, and some decking manufacturers recommend that specific brand on their own websites as well. Corte*Clean has a website too, with helpful information including a video.

Here are some basic steps for using Corte*Clean:

Step 1: Prep Composite Deck for Cleaning

First, remove all items from the deck. Corte*Clean should be applied to a clean, dry deck surface, so use a blower or broom to remove all loose material from the deck before getting started. You'll get the best results if the temperature is between 65 and 85 degrees, so this product is especially suited to the Pacific Northwest. If the temperature is outside of that range, check the manufacturer's instructions for guidance. Be sure to protect any non-composite parts of the deck by masking them off; this includes non-composite railing systems like aluminum or glass. Wet down any plants adjacent to the deck to help protect them. 

composite deck with furniture
rinsing plants

Step 2: Mix Corte*Clean Solution

As per the manufacturer's directions, mix the dry crystals into water until they are completely dissolved. Using warm water will help dissolve the crystals more quickly. You'll be putting the solution through a pump sprayer, so it's important that the crystals be dissolved or you'll clog the sprayer nozzle. A scoop is included inside the Corte*Clean packet. Use five scoops to a gallon of water for heavy, "maximum strength" cleaning of tough stains on your composite deck. You'll only need about 2-1/2 scoops per gallon of water for routine maintenance cleaning. Pour the solution into a pump-up garden sprayer.

corte clean mix for composite deck
adding water to corte clean for deck cleaning

Step 3: Apply Corte*Clean to Composite Deck

Working in smaller sections—like a 10' x 10' space—will give you the best results. Spray on the solution and let sit for up to 20 minutes. You can scrub with a deck brush after five minutes if you have heavily soiled or stained areas. Consult your deck board manufacturer for their recommendation on whether to use a synthetic or natural bristle brush. 

While working, make sure to keep the surface wet. If the cleaning solution starts to dry on the surface, apply a new mist to those areas.

apply corte clean to composite decking

Step 4: Rise Composite Deck Well

After a thorough rinse, you may notice bubbles remain on the deck. The bubbles are part of the Corte*Clean design, and will reactivate to clean the deck when it gets wet again. When you're finished rinsing the deck, rinse any surrounding vegetation as well. 

We usually recommend a maintenance cleaning at least twice a year so you stay ahead of heavy build-up or staining. Following these basic steps will beautify your composite deck and help prolong the life of your outdoor living space. 

How to Clean a Composite deck
Build Your Deck With Dunn Lumber