Decks require scheduled maintenance to refresh their beauty and strengthen their protection against the elements.
Maintenance-free decking is a no longer an industry term—manufacturers know that all decks require maintenance if they are going to last. So, it's best to understand what your deck is made of and the maintenance schedule you should follow for a long-lasting deck.
Deck Washing Because they are outdoor living spaces and horizontal surfaces, decks catch a lot of dirt, grime, mold, and organic matter. A good cleaning keeps the deck surface looking nice and is an essential step before sealing or staining. There are many cleaning products available, but it is important to match the correct cleaning product to your deck material to achieve the best results.
Consider renting or buying a pressure washer, as a garden hose may not be powerful enough to remove dirt and chemicals. Be careful not to use too much force—anything stronger than 1200 psi could damage the wood or the composite decking. "The goal is to use the lowest pressure possible to get the job done," says Mark Crump of Be Clean Pressure Washing Services, a deck maintenance contractor in Virginia. "The ideal is for high volume, low pressure." To reduce the pressure of a washer, a homeowner should use a tip with a wider spray. Tips range in size from 0 degrees (which is highly dangerous) on up. Use a 45 degree nozzle with a wide fan pattern for wood surfaces. Above all, take care not to damage your deck.
Pressure-washing a vinyl deck is fine. Homeowners can even use a smaller nozzle since vinyl will not break down like wood under a high-pressure stream. Deck manufacturers may recommend cleaners, but a mild detergent wash followed by a good rinse is usually enough.
Deck Cleaning Selecting a cleaner for a wood or composite deck might seem like a daunting task, as there are many options and a variety of active ingredients. The goal of the cleaner is to loosen the dirt from the surface of the deck to allow for an easy wash and rinse. "The cleaning agent releases the dirt. The best cleaning agents allow for the lowest possible pressure when washing," says Crump. Cleaners can be chlorine bleach, oxygenated- bleach, or an acid of some type.
Chlorine-based bleaches are effective against molds and mildews— common enemies of the composite deck. Some professionals advise against using a chlorine bleach cleaner on a wood deck, suggesting that it dries out the deck. Chlorine bleach can also be harmful to surrounding vegetation, particularly when not diluted properly.
Oxygen-based bleach cleaners, also called oxygenated bleach, are environmentally friendly alternatives to chlorine-based bleach. They are effective in removing molds and mildews as well as dirt.
Acid-based cleaners are sometimes referred to as brighteners or neutralizers because they neutralize the alkaline effect of a bleach cleaner and balance the pH of the surface to prepare it for the stain. Some stains and sealers work best when applied to a deck surface that has been neutralized.
Some composite deck manufacturers recommend treating a deck with a protector to guard against stains, molds, and mildews. It is best to check with the manufacturer for recommended deck cleaners. Some say to use only cleaners with sodium hypochlorite or chlorine bleach.
All Woods Are Not the Same
Soft woods like cedar and redwood can turn an unnatural dark color when a bleach is used to clean them. Mathew McKinley, yard manager for Redwood Products, will not use bleach on a redwood deck. "Bleach can destroy the molecules of the wood," he says.
McKinley recommends using oxalic acid on redwoods and cedars. "Oxalic acid acts as an effective brightener," he says. Oxalic acid brings back wood's natural color. Citric acid cleaners are similar to oxalic acid cleaners, and are even a bit milder.
Follow the directions on any deck-cleaning product. Some cleaners recommend that the deck be wet prior to application. Other cleaners contain chemicals that can damage the surrounding vegetation, in which case you must water surrounding plants and cover them during application and rinsing. Cleaners may also require dilution. The amount of time a product must sit on the surface before rinsing varies widely, as does the prescribed amount of drying time before staining or sealing.
Staining and Sealing Once a deck has been cleaned, it should dry thoroughly before applying a stain or a sealer. Most professionals recommend waiting 24 hours after a cleaning. Homeowners should consider applying a stain during the cooler part of the day, particularly if living in a hot, sunny climate. "Some products are temperature-sensitive," says Matthew McKinley, of Redwood Products, who prefers to stain in the early morning hours after the dew has burned off.
Sealers can protect wood decks against moisture, but offer no protection against UV damage from the sun, which will turn a deck grey. Stains are basically tinted sealers that provide that UV protection. The darker the tint, the greater the UV protection. Most stain and sealer manufacturers recommend waiting at least 24 hours before using the deck after applying the product.
Hiring a Pro Professional pressure-washing services and deck-maintenance contractors are a viable option for homeowners. They will have access to high-quality cleaners that are harder for the individual to come by, and they may use commercial airless sprayers and professional-grade pressure washers for a consistent clean-and-stain application. They are also able to get the job done quickly. "When we do a job, we are often able to clean the deck in an hour, and stain it in an hour," says Crump. When considering paying for a professional clean and stain, homeowners should make sure the contractor inspects the deck prior to quoting a price. "Most contractors will base the price on time and materials, and they price by the job," Crump says. Using a 10 foot x15 foot deck as an example, he suggests that a wash and a stain would cost about $100 and $150, respectively. Cost for a professional wash and stain will vary by region and by the size and nature of the job.