Design & DIY

How do you extend the life of an untreated cedar deck?

Cedar deck Photo by Tab62/Shutterstock

What can we do to extend the life of our untreated cedar deck?

—Sheri Krastel, Lac La Biche, Alta.

Happily, untreated cedar is already long-lasting and durable because it has some decay resistance, thanks to naturally occurring extractives originating from the tree’s heartwood. “But these do have some water solubility,” says Paul Morris, a research leader for wood protection at FPInnovations in Vancouver. “So the key is to help the wood dry out faster after a rain event.” Increase ventilation under the deck, regularly get rid of leaves, pine needles, or moss on top of the deck and between the boards, and periodically move furniture—benches and tables—to allow the wood underneath to dry.

You can also treat your deck with a product that will help the wood shed water. Use a penetrating stain or finish. Unlike a paint, it won’t form a film (which can peel or crack). “Pay particular attention to any exposed cut ends,” says Morris. “The end grain is where water gets in, and extractives get out.”

Jake van Schothorst, the general manager at Prairie Cedar in Coalhurst, Alta., recommends a semi-transparent finish, such as C2 Guard, to help preserve your cedar. (Products that are labelled “semi-transparent” contain UV blockers and pigments.) You’ll have to reapply this—how often will depend on the product and the day-to-day weather conditions that your deck will face.

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