Choosing the Best Composite Decking for Boat Docks in Minnesota, the Land of 10,000 Lakes

best composite decking for boat docks

It takes a lot of maintenance to keep a wooden boat dock or lakeside deck looking good year after year, but the newest composite materials stay moisture-resistant without staining, sealing, or painting.

As a young man, one of my first summer jobs was getting the lakeside piers and decks ready for the spring after the long and cold winter. The piers that weren’t able to be fully disassembled before winter would always require a mountain of work. Even with marine-grade paint, the constant moisture and sun exposure took a toll on the wooden docks.

Apart from the hours of scraping and sanding and painting, there were always warped or cracked boards in need of replacing. It was good work for the soul, but even with our low wages, it was clearly an expensive proposition as we only worked on city-owned docks and those of the wealthier residents. Other homeowners worked on their docks themselves, or let the maintenance go.

It’s understandable. When a structure is only usable for roughly half of the year, a lot of people may stop doing what seems like endless maintenance, and forego the pleasure of a dock altogether. Yet, having grown up in a lake town, I know how integral lakeside decks and docks are to the social and cultural life of a family and community. That’s why I’ve been excited to see a new breed of low maintenance, moisture-resistant composite decking emerge.

Until very recently, composite decking materials had real difficulties dealing with moisture, and homeowners and builders wisely avoided using them near bodies of water. However, changes in technology have resulted in the development of fully-capped bamboo-based composites which are some of the best composite decking for boat docks that I have come across in my years of building. These composites are making it possible to own a beautiful lakeside deck or dock without doing expensive (and back-breaking) maintenance on it every year.

Keeping Moisture from Collecting Underneath a Boat Dock

The big challenge of keeping a dock free of moisture is brought on less by the waves lapping to and fro and more by the nighttime condensation of water that evaporates during the day. Moisture collects on the cooler, shaded underside of docks, and finds its way into the planks and boards. This is the case with decks as well, but it is an especially relevant issue when dealing with a structure that stands over or right next to a large body of water. And while the top and the sides of dock boards can be painted year after year with relative ease, this is not so for the underside.

Some people go to great lengths to keep the underside of a dock free of moisture (and to protect the dock from the damaging winter freeze/thaw cycle that’s so hard on wood). For instance, many of the docks I worked on as a young man were assembled and disassembled every year, with each board numbered so that it would be put back into the same place year after year. Each time the dock was reassembled the boards would be sanded down and painted before being screwed in—more work than most are keen on! There are certainly better options when it comes to deck maintenance.

Fully-Capped Is the Best Composite Decking for Docks

While the first generations of composite decking weren’t particularly well suited for close proximity to so much moisture, composite decking that is encased by a rigid cap on all sides, referred to as ‘fully-capped’, proves highly effective at keeping moisture at bay. This does away with the need to maintain the hard-to-reach underside of the dock boards. As with any product, not all of these caps are equally durable and moisture-resistant. Some manufacturers are now making a board that is fully capped with a tough, engineered resin that draws on technology from the tire industry to resist moisture and stay grippy when wet. As well as being moisture resistant, the capping is also UV resistant, eliminating the need for painting and sealing to protect the boards from weathering and graying.

In addition to a durable protective capping that surrounds the board, some new composite decking incorporates bamboo flour as a filling material, replacing the sawdust that was traditionally used. Sawdust causes problems in composite decking because of its tendency to clump together during the manufacturing process, turning the clumps into reservoirs for any moisture that penetrates the capping. Bamboo flour, on the other hand, does not clump, and the even distribution of it and the recycled plastic makes the board extremely resistant to water. These features—tough, full capping and a moisture-resistant core—make these decking materials some of the first viable, low-maintenance composite alternatives to wood.

Decades after my seemingly endless teenage dock maintenance projects, I am now able to build lakeside decks and piers for my clients that don’t require legions of inexpensive teenagers to perform intensive maintenance on them. I do this by taking advantage of the fruits of materials science, and installing fully-capped composite decking. There are some good decking brands out there, but I often recommend Infinity Decking, which is a uniquely durable bamboo-based product from Fortress Deck. When I need to incorporate other elements into a project, I usually take a look at the full range of Fortress Building Products’ beautiful and innovative fencing, railing, and decorative hardware.

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