Cumaru Decking Finishing Guide: Our Tips and Tricks

Cumaru offers breathtaking natural beauty and impressive durability, making it an ideal choice for decking material. Properly finishing your Cumaru is crucial to enhance and preserve the wood’s natural qualities. With proper care, your Cumaru deck will be a stunning and functional aspect of your outdoor space for decades to come. As one of the hardest Brazilian woods on the market, it has an impressive life span of 50 years or more. Follow these suggestions for finishing and caring for your deck to ensure your Cumaru lasts as long as possible and retains its lovely appearance.

Understanding Cumaru Wood

Cumaru is a South American hardwood lauded for its strength and longevity. Cumaru contains silica, making it naturally rot-resistant so that it can withstand weather and water well. Because Cumaru is so hard, it mills beautifully but can also be hard on your tools. Cumaru is popular for commercial construction projects because it can withstand high traffic and extensive wear. That same durability can serve you beautifully in your residential projects.

Cumaru varies in color, presenting a bold and distinctive look. It ranges from reddish brown to golden tan in color. You may find hues of purple and red in darker Cumaru or yellow and green streaks in lighter-hued planks. You’ll typically find a few dark grain accents throughout the wood. Exposure to sunlight gives Cumaru a silver or grey appearance. Cumaru becomes fluorescent under a black light; this trick distinguishes it from Ipe, which has many comparable qualities.

Preparation for Finishing

Before you begin the process of finishing your Cumaru, you must thoroughly clean and sand the surface. You’ll need to take a more aggressive approach to the cleaning process if it has a previous layer of finish. If it does, you’ll apply a stripping agent to the wood. Let this sit for a few minutes, then gently power wash it to strip away any previous coating.

If your Cumaru is unfinished, skip the previous step and begin with an oxalic acid-based cleaner. Many cleaning products come with a spray nozzle, which is sufficient for application. You can also use a garden hose to spray the cleanser on the surface of the wood. Scrub the decking with a stiff brush to work the product into the wood and remove dirt and grime.

Once the wood is clean, apply a brightening agent to it. Over time, Cumaru naturally greys. If left unfinished for a long period, it will darken to a near-black hue. Brightening the wood will help restore its original color, balance the pH, and condition the wood for staining.

Selecting the Right Finish for Cumaru Decking

Cumaru is exceptionally dense and alkaline, which makes it resistant to many finishing products. If you use the wrong finish, you’ll find that the product simply won’t dry. Many opt for an Ipe oil (formulated for dense woods) since it’s similar to Ipe in composition. Other oil-based products like tung oil may also work well on your Cumaru deck. Don’t use a water-based finish, as this will not penetrate the wood properly.

Application Tips for a Perfect Finish

Cumaru decking has a brilliant and attractive appearance when finished properly. Make sure you get the best possible results from your finishing project with the following tips:

• Let the Cumaru dry completely between each step in the finishing process. Give the wood three to five days to dry after pressure washing, and wait 24 to 48 hours after you apply the brightening agent, increasing the drying time if you’re dealing with wet or humid weather.
• Test your finish on an inconspicuous part of the deck before you begin. You need a different product if the finish stays tacky and refuses to penetrate the wood.
• Follow the manufacturer’s directions on all deck cleaning, brightening, and finishing products. The instructions here are only recommendations and should come secondary to the directions provided by the products’ manufacturers.
• Don’t skip the wiping step — if the stain instructions say to wipe down the wood, roll out a thick covering and then go over it with a cloth to wipe it across the boards. Wait no more than 30 minutes between rolling the stain on and wiping it over the wood.

Post-Finishing Maintenance and Care

To extend the life span of your beautiful finish, consider applying an oil-based sealer to the wood. Most sealers will last one to two years before you must reapply them. However, Cumaru is a very strong and low-maintenance wood, so you can probably extend the time between sealing projects.

Clean your deck with soapy water and a soft brush every two or three months. This will keep dust, dirt, and grime from building up on the boards. The more often you clean your deck, the quicker and easier the job will be.

Inspect your deck often for any signs of damage. Cumaru’s impressive strength makes it stand up to regular wear and tear wonderfully, but you may still find things like loose screws or nails or damaged wood. A simple visual inspection two to three times a year will help you spot problems early before your deck sustains any kind of serious damage.

Professional Refinishing Services

While you can perform simple maintenance tasks independently, it’s best to turn to a skilled professional for major refinishing projects. Our experienced team at Teak Master has the knowledge and tools necessary to restore aging Cumaru to its natural beauty. We understand all the finer points of Cumaru and know how to work with its impressive density and strength. Our thorough wood deck refinishing process includes cleaning, conditioning, repairing, and refinishing the entire deck so the results look and feel like new. Contact Teak Master today for a personalized quote on your Cumaru deck project.