Building Outdoor Composite Decks in Harsh Climates


It’s not easy building structures to withstand our constantly changing weather conditions in the northeast. Unlike some portions of the United States to our south and west who can barely identify TWO seasons, the opportunities (and challenges) associated with our 4-season weather patterns are loved by many, but endured by all.

That said, these widely fluctuating outdoor weather conditions, ranging from scorching sunshine and 95°(F) temperatures to pounding rain, salty air, snow, ice, and sub-zero cold, can be brutal on any outdoor exposed surface. These are some of the reasons that the building construction practices in New England are so different from other parts of the country. From roofs to exterior cladding on homes to decks and patios, special care is needed to help ensure each performs as needed for as long as possible. 

Over the past several years, homeowners have begun installing new decks using composite decking materials made with recycled plastic instead of traditional pressure treated lumber. Not only does the composite decking material require less maintenance, it also withstands extreme weather conditions better than traditional lumber.

As material and manufacturing costs also continue to fall, the pricing gap between traditional wood and composites is also shrinking. This last fact makes installing a long lasting, wood-like profiled composite deck a more affordable option than ever before.

Here are few important ways to keep your new composite deck performing well no matter what Mother Nature decides to throw at it.

Choosing the Right Composite Decking Materials

When materials such as pollen and dirt are allowed to remain on any outdoor surface, mold can become a growing problem. Mold and mildew is not only ugly, it can also ruin the surface it has attached itself to. Although all composite decking is inherently less susceptible to mold and mildew damage (when compared to traditional lumber) earlier composite decking still required the use of harsh chemicals and cleaners.

Today, newly developed composite materials, such as DuraLife polypro composite decking, now only require occasional cleaning with warm soapy water and a soft brush – similar to washing a car. It’s just that easy!

When Digging Deck Footings, Dig Deep

If you’ve ever traveled through northern New England in late winter or early spring, you’ve likely noticed roadside signs warning of “frost heaves.” The phrase describes not only a specific thing (a dramatic, yet sporadic bump in the road) but also an action (as temperatures fluctuate just above and below 32°(F) accumulated water underground freezes, expands and heaves the solid earth and pavement above it up, creating a ridge on an otherwise flat, level surface).

The same principle action can occur to virtually any solid, static item surrounded by earthen material containing water. To keep frost from heaving the footings of a new deck, causing boards to warp and potentially damaging its structural integrity, its important to install footings at a depth below the frost line.

Depending on your location, the frost line can vary from several inches to 3’ to 4’ feet. Installing footings at the correct depth allows the static footing to absorb the expansion and contraction of the material surrounding it without causing it to shift – taking the deck with it.

Slope It. Slope It Good

Another way to help keep the elements from damaging your deck is by creating a way for water and debris to naturally flow off and away from both the deck surface and its base below. To prevent water from puddling up on or under the deck, both surfaces should be installed with a slight slope (or angle), creating an escape route for water to flow.

While solutions exist for creating a completely dry space underneath a deck – by installing synthetic membranes and gutter systems to transport the water to a specified drainage area away from the building the deck is attached to, it is not necessary to go to this extreme. 

The important thing for homeowners to keep in mind is that decks are designed to allow water to flow over and through it. When this happens, the surface below must be able to absorb and/or transport the water to where it can evaporate into the atmosphere. Otherwise, the cool damp environment that’s created will ultimately cause the decks framing to fail prematurely as well becoming a favorable breeding ground for mosquitoes and other pests.

Get Samples shipped to your home or contact DuraLIfe now to learn more.

This article is made possible by DuraLife.DuraLife’s unique polypropylene and hardwood composite decking materials simply outperform all other wood and composite decking products.More solid and safe under foot, DuraLife decking is backed by a 25-year warranty. It is stain and fade resistant, mold and mildew resistant, and is available in the colors and deck railing options you want. Get Samples, try our Composite Deck & Railing Visualizer, or contact DuraLIfe now to learn more.