Cleaning your deck prior to applying sealers or paints
Wood decks built with CCA treated lumber should be cleaned and sealed to keep the chemicals from being washed out of them and into the soil. Cedar decks and other non-treated wood materials should be cleaned thoroughly, before applying a sealer.
Pressure washing wood decks can erode the soft wood of the lumber used on your deck rails and floors. It may even splinter the wood off you deck in some vulnerable areas.
Do not use any form of Chlorine Bleach as a deck cleaner, as it will damage all of the components of your wooden decks and is toxic to surrounding plantings. Chlorine bleach will also discolour the wood. Oxygen bleach cleaners are non-toxic – and clean wood beautifully. Oxygen bleach forms a froth on the deck and the millions of oxygen bubbles will deep clean the wood while you watch.
Carefully read the instructions detailed on any cleansing product’s label, to be sure that it is an appropriate product to apply to the materials used in your new deck construction.
In many cases, you can simply use water from a garden hose sprayer nozzle, to remove any dirt particles from the crevices in and around the deck. Be sure that all wood surfaces are fully dried prior to applying you chosen wood sealant or paint product.
Tips about Deck Sealers
Not all deck sealers or water repellents are created equal. Film forming deck finishes contain clear resins that soak into the wood but they also lay at the surface. A film on any horizontal wood deck or railing is not desired. Penetrating water repellents are a much better choice. They soak deeply into the wood and stop water penetration.
Intense ultraviolet (UV) rays in sunlight blast away at horizontal deck surfaces during the mid part of the day. These same rays glance off vertical railing pickets. This is why your flat surfaces always look worse than the railings. Add to this the fact that rain and snow will puddle and stand on the horizontal decking and flat hand rail tops. The UV rays and water vigorously attack the film finish. The net result is that the weakened film finish peels off rapidly and readily.
You should seal your wood decks with a synthetic resin sealer, which has no oils to feed the growth of mildew or algae. Simply check the ingredients on the label of any wood sealer product or ask the sales representative at your local building supply centre, to ensure that you are buying the right sealant for you deck or wooden structure.
Painting or using Water Repellents – consider the choices
Water repellents and paints are both coatings. Paint is considered a film that lies on top of the surface. Many water repellents soak into the wood and do not leave a film at the surface. Some water repellents do create a film or skin at the surface. The problem with films or surface coatings is that they eventually peel. When this happens, you are forced to scrape or strip the loose and peeling film off before you can apply a second coat. For this single reason, try to avoid coatings that leave a film.
If you do decide to paint instead of applying an epoxy fortified synthetic resin water repellent, be sure that you thoroughly wash the wood – but again, avoid pressure washing the delicate wood. Carefully read the label of the finish paint product you choose and follow the directions with respect to any primer they say you must use. Never forget that paint is simply a form of glue with colour added to it. Both the primer and the finish paint will adhere optimally to a clean and dry surface.
If you choose to paint, you should use a paint product that contains a blend of water-based urethane and acrylic resins. These are very sticky to apply by the up side is that it will be many years before your paint film peels or blisters. The urethane – acrylic resin paints are readily available. They are sold at national chain paint stores as well as several major retail stores that have tool and paint departments.
Look at the label and when you see the words “urethane and acrylic”, you know you have the right one. Be sure to pay strict attention to the temperature ranges when the paint can be applied. Do not stray outside of these ranges.
The best weather to apply paint is when the temperature is around 21° Celsius (70° F) and the winds are calm. An overcast day is much better than a sunny day. It is best for paint to dry slowly, as this allows the product to set in.
Penetrating Water Repellents
Penetrating water repellents do not peel, but they wear out. When it is time to re-coat the wood, you do not have to scrape the wood clean prior to applying the new coating. This can save a tremendous amount of work. You will still have to carefully and thoroughly wash all areas and then do what is necessary to apply the coating of your choice. Scraping or stripping loose films should be done prior to washing the wood with your method of choice.
Semi-transparent water repellents for wood come in many different formulations. Unfortunately a majority of them are made from natural oils that are food for mildew and algae. The best water repellents are ones that are made from synthetic resins. Before you buy a sealant or repellent, ask your supplier about the contents to confirm if they are made from natural oils or synthetic resins.