As painting contractors, we often wrestle with how best to refinish old and neglected pressure-treated wood decking – without call backs. One common problem as treated southern yellow pine ages is splitting and checking, opening up the grain to moisture penetration and grime build-up. These are perfect conditions for a mildew infestation to take root, leading to slippery walking surfaces – not to mention diminished visual appeal. It’s tough to achieve finishing success under these conditions, which is why there are so many vintage PT decks with peeling, flaking and fading finishes.

Another problem is that during the lifespan of an older deck, maintenance is often done by non-professionals who don’t properly prep the surface and who use lower-grade products that have been improperly applied. By the time a pro shows up, the deck usually requires a partial or full-on restoration.

Solid vs. Semi-solid finishes

Until recently, our finish choices for restoring PT decking have been limited to semi-solid and solid stains. Semi-solid stains are a good compromise that give the decking a richer color while still allowing it to look and feel like wood. But while semi-solids apply easily and look good, they typically require annual maintenance to stay that way.

Solid stains last a little longer, a couple of years or so on properly prepared decking, with just some fading before the finish starts to wear out and need refreshing. We’ve had good success with Sherwin-Williams Deckscapes, for example, though there is a definite need for regular maintenance. But solid stains are risky, because their tendency to flake and peel can create a lot of annual backwards motion. And if they do fail, it is a bad failure that is hard to reverse, usually requiring a full-on strip.

The Elastomeric Option

Looking for another solution, we recently made the leap from conventional solid decking stain to elastomerics by using Duckback SuperDeck Deck & Dock on a few projects. This elastomeric coating is formulated specifically for use on heavily weathered and damaged wood on horizontal outdoor surfaces subject to exposure and high traffic.

Instead of using a traditional stain, the author chose to refinish the decking with an elastomeric coating, which is characterized by a high solids content.
Scott Burt Instead of using a traditional stain, the author chose to refinish the decking with an elastomeric coating, which is characterized by a high solids content.

We’ve used elastomeric coatings before. They’ve long been a noteworthy solution for high-risk finish applications such as concrete, masonry, stucco, and even metal roofing. The difference between elastomeric and conventional paint/stain technologies is that elastomerics have higher solids contents, and can be 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, of course, there may be nothing more high-risk than decks.

Application

Back in 2013, we applied Deck & Dock to the 18-year old pressure-treated decking of both a porch and a deck on a Vermont home with harsh mountain exposures. In our case study, the porch and deck were on two different sides of the same large house, allowing us to see how the product performed in both full sun (dry) and shaded (frequently damp) conditions.

Careful pressure-washing with a Jomax-and-bleach solution removed mildew and dirt from the decking.
Scott Burt Careful pressure-washing with a Jomax-and-bleach solution removed mildew and dirt from the decking.

We initially pressure-washed the PT decking to remove grime build-up, mildew, and loose materials using our standard  Jomax/bleach solution. Then, we scuff-sanded the decks with a pole sander and hand blocks using 80-grit paper. While we’re big advocates of using power sanders with dust extraction for prepping surfaces for finishing, particularly for tropical hardwood decking, we find that it sometimes works against us when working with PT southern yellow pine decking. It’s better to keep the grain open and fill it with product.

Because Superdeck Deck & Dock is formulated to be used on existing surfaces (as opposed to new or specifically raw wood), it was not necessary to do full chemical or mechanical stripping on a large scale. There were a few boards that required a little extra attention, particularly ones that were peeling and flaking from traffic and exposure to underside moisture. But the majority of the decking retained its base layer of existing finish, which was clearly older penetrating semi-solid oil stain (the type that gets applied for so many years that it starts to pretty much look solid).

In most cases, power sanding isn't required to prep old decking for a new elastomeric coating; here, the author used it to  remove flaking and peeling areas in the finish.
Scott Burt In most cases, power sanding isn't required to prep old decking for a new elastomeric coating; here, the author used it to remove flaking and peeling areas in the finish.

Deck & Dock is intended to be applied heavily for surface filling purposes, so we were able to really apply it quickly. One of the great ironies of painting is that it usually takes more time to apply material moderately – and properly – than it does to apply it more heavily. Less-experienced painters and DIY-ers often apply too much paint or stain by accident, a bad thing when the product is not intended to be applied that way. But when a coating is formulated for heavy application, it’s great.

We expected Deck & Dock to be perhaps a bit “draggy” because of the high solid content, but it turned out to be slick enough to lay out by brush on pretty rough decking with lots of surface imperfections. It was easy to achieve the recommended 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 with a conventional stain.

Since this is a waterborne acrylic-based product, dry times are quick and cleanup is a breeze. Working in ideal summer conditions – warm, somewhat humid, a little breezy and with no rain in the forecast – the finish dried to the touch between 1-2 hours, and was dry enough to get back on within 3 to 4 hours, the time-frame that the manufacturer recommends for a second coating. Two coats, one day, done…that is a desirable and profitable turnaround.

This is what the porch looked like prior to applying the new elastomeric coating.
Scott Burt This is what the porch looked like prior to applying the new elastomeric coating.
Here's the porch after the new elastomeric coating has been applied to the PT decking. After 3 years of harsh Vermont weather, the finish is still going strong.
Scott Burt Here's the porch after the new elastomeric coating has been applied to the PT decking. After 3 years of harsh Vermont weather, the finish is still going strong.

Duckback recommends 24 to 48 hours of curing time, depending on weather conditions. We opted to play it conservatively and wait the full 48 hours before returning the porch to service, which is still a pretty quick turnaround. When restoring a deck, reducing the amount of down time is a definite convenience to customers, but forcing a slower product to be fast just about guarantees problems down the road.

Observations

When we refinish decks, we always check on them later on to see how they are holding up, typically at the 6-month mark when using products we are experienced with. With new products, we check them at two to three month intervals, and especially with changes of season. So far, we’ve checked our case study deck and porch four times now, and remain impressed with the results.

Originally applied to the decking in September 2013, the elastomeric finish has now seen several changes of seasons, endured temperatures well below zero, and been exposed to high winds, piles of snow and, of course, shoveling. So far, the decks are none the worse for wear, making us optimistic that SuperDeck Deck & Dock could prove to be a good long-term solution for badly weathered and damaged – but structurally sound – pressure-treated decking.

Scott Burt owns Topcoat Finishes in Jericho, Vt. He enjoys discussing finishes at topcoatreview.com, where this article originally appeared. He and business partner Todd Pudvar also host ipehelp.com for homeowners and contractors with ipe emergencies.