For decades, painters have wrestled with how to best refinish neglected, old pressure treated decks – without call backs. Pressure treated decks are common in the residential repaint segment, because the wood rarely rots, but often seems to take on every form of ugly just shy of rotting.
Splitting and checking are typical in pressure treated wood as it ages, which makes finish success difficult to achieve. When decking wood dries out and splits, the grain becomes very open to moisture penetration and grime build up – a recipe for deck finish failure over time.
This is why we see so many vintage pt decks with peeling, flaking and fading finishes. It is a perfect condition for mildew infestation to take root, leading to slippery (unsafe) walking surfaces – not to mention diminished visual appeal.
In many cases, during the lifespan of an older deck, maintenance is often done by non-professionals, with a lack of proper surface prep and lower grade deck products applied too heavily. By the time a professional shows up, it is often a partial or full on restoration.
Fortunately, people love their decks, and it can be pretty easy to help them understand the quality of outdoor life they are missing by having a deck that is generally unsuitable for optimum enjoyment.
What Are the Options?
Southern yellow pine is a common wood species manufactured as a pressure treated deck material. It is well understood that this is usually not a “select” grade of wood, meaning that it is not the prettiest grained pine available. So, it is rare that a customer or painter would ever want to do a clear penetrating finish on pt wood. For those who have done it, there is no mistaking the disappearing act that happens. And if over applied, a cloudy or muddy wood tone usually results. So clears are pretty much out.
When wood is not especially pretty, but needs to be preserved, semi-solid stains are often a good compromise of color introduction, while still allowing the look and feel of wood. Semi solids apply well and look good, but are high maintenance – likely annual maintenance.
And, of course, the other obvious option is solid stain, which is risky because they can have a tendency to flake and peel, which creates a lot of annual backwards motion. If they do fail, it is a bad failure that is hard to reverse, usually requiring a full on strip.
There are some solid stains, such as Sherwin Williams Deckscapes that are highly capable of success on properly prepared pt decks. We used that product for several years with no failures, but the definite need for regular maintenance. In most exposures, it can go a couple of years with just some fading before it starts to wear out and need refreshing.
What Could Be Better?
Elastomeric coatings have long been a noteworthy solution for high risk finish applications such as concrete, masonry, stucco and even metal roofs. The difference between elastomeric and conventional paint/stain technologies is that elastomerics have higher solid contents, and can applied much thicker. These coatings are engineered to reject water infiltration and to have “filling” qualities for surfaces with cracks and voids. They can even lock down splintering tendencies in wood. In residential exterior painting, there may be nothing more high risk than decks, raising the question of practicality for a more bullet proof solution.
Last September, my company made the leap from conventional solid decking stain to elastomerics. We tried a product called Duck Back Super Deck, which is an elastomeric coating intended for decks and docks. This line is formulated specifically for use on heavily weathered and even damaged wood on horizontal outdoor surfaces with exposure and high traffic. It is recommended for all types of traffic and abuse just shy of being driven on by automobiles.
We applied Duck Back on a few old pressure treated decks in harsh mountain exposures, in both full sun (dry) and shaded (frequently damp) settings. Our case study to measure the success of the product was two decks on two very different sides of the same large house.
Both decks were initially pressure washed to remove grime build up, mildew and loose materials. Then, the decks were scuff sanded at 80 grit. Because Duck Back is formulated to be used on existing surfaces (as opposed to new or specifically raw), it was not necessary to do full chemical or mechanical stripping on a large scale. There were a few boards that required it, but the majority of the decking retained its base layer of existing finish, which was clearly older school penetrating semi solid oil stain. You know, the type that gets applied for so many years that it starts to pretty much look solid.
Because Duck Back is intended to be applied heavily for surface filling purposes, we were able to really apply it quickly. Sometimes we lose sight of the fact that applying more material is actually faster than applying moderately. This is one of the great ironies of painting, and it is very much a two edged sword. Less experienced painters and diyers often apply paints and stains too heavily by accident. When the product is not intended to be applied heavily, this is a bad thing.
When a product is built for heavy application, it’s great. We expected this product to be perhaps a bit “draggy” because of the high solid content, but found it to be slick enough to lay out by brush on pretty rough decking with lots of surface imperfection. It was easy to achieve a 16 mil wet thickness, laying the product out and just letting it level into the surface. The film thickness capability is significantly beyond what one would expect to achieve with a conventional stain.
The Good News
Because this is a waterborne acrylic based product, dry times are quick and cleanup is a breeze. The turnaround is a bit remarkable. At heavily applied millage, the product dries to touch between 1-2 hours. We found it to be dry enough to get back on within 3-4 hours, and the manufacturer recommends that second coating can be done within that timeframe. Two coats, one day, done. That is a desirable and profitable turnaround.
We found that 48 hours was sufficient for curing and return to service. With decks, reducing the amount of down time is a definite convenience to customers. Having a product that is capable of quick turnaround is key, because we all know that you can’t force a slower product to be fast. That just about guarantees problems down the road.
How’s it Holding Up?
When we refinish decks, we always return to check how they are holding up. When using products we are experienced with, we inspect at the 6 month mark. With new products, we check them in 2-3 month intervals, and especially with changes of season. We have checked our two ear marked case study decks twice so far.
So far, so good.
The Duck Back we applied in September has seen the change of seasons, endured temperatures well below zero, high winds, piles of snow and, of course, shoveling. We are pleased to note that through the first couple of check ins, the decks are none the worse for wear.
If you are looking to ramp up your deck refinishing program this season, particularly for badly weathered and damaged pressure treated decks, this could be a really good solution. Duck Back Super Deck is available through Sherwin Williams.