How do I prepare my deck for winter in Moncton NB?

Begin your winter preparation in late October or early November by thoroughly cleaning the deck, inspecting all structural connections for summer damage, applying or refreshing a protective sealant if needed, and removing all items that can trap moisture or be damaged by freeze-thaw cycling — the goal is to send the deck into Moncton's 5-month winter season in the strongest, cleanest, driest condition possible.

Moncton presents a particularly harsh combination of winter conditions for deck structures. The city receives approximately 300 cm of snowfall annually, experiences snow loads between 2.0 and 3.5 kPa, and endures dozens of freeze-thaw cycles between November and April as Maritime weather systems alternate between cold Arctic air and milder Atlantic influences. Each freeze-thaw cycle drives moisture deeper into wood grain and widens existing checks and cracks, so minimizing the moisture content in your deck's wood before the first freeze is the single most impactful thing you can do.

Start with a thorough cleaning. If the air temperature is still above 10 degrees Celsius, power wash the entire deck surface, railings, and visible framing using a fan tip at moderate pressure — 1,500 to 2,000 PSI for pressure-treated wood, 1,000 to 1,200 PSI for cedar or composite. The objective is to remove dirt, mildew, leaf debris, and any organic matter that holds moisture against the wood surface. Pay particular attention to the gaps between deck boards where debris accumulates and traps water against the joists below. Allow the deck to dry completely for at least 48 hours before proceeding.

Inspect all structural connections while the deck is clean and visible. Check the ledger board flashing to ensure water is being directed away from the house wall. Examine joist hangers and post connections for corrosion, particularly if the hardware has been in place for more than 8 years. Look for any posts that have shifted due to frost heave — posts that have lifted even slightly indicate footings that may not extend to the full 1.2 to 1.5-metre frost depth required in the Moncton area.

If your deck is pressure-treated or natural wood, check whether the existing sealant is still functional by splashing water on the surface. If the water beads up, the sealant is intact. If it soaks in and darkens the wood, the sealant has worn through and the wood will absorb moisture all winter, leading to accelerated checking, splitting, and cupping through freeze-thaw cycling. Apply a fresh coat of penetrating deck sealant while temperatures remain above 10 degrees Celsius.

Remove all planters from the deck surface. Planters sitting on deck boards trap moisture underneath constantly, and freeze-thaw cycling will crack both the planters and the deck boards beneath them. Bring all deck furniture indoors to a garage or shed if possible. If indoor storage is unavailable, use breathable furniture covers rather than plastic tarps. Tarps are not recommended because they trap moisture against surfaces, prevent air circulation, and create conditions for mold growth even in cold weather.

If you have a hot tub on the deck that you will not use over winter, winterize it by draining all water, blowing compressed air through the plumbing lines, adding plumbing antifreeze to the jet lines and pump housing, and securing an insulated cover. Any water left in the plumbing will freeze and crack fittings.

Finally, prepare your snow removal tools. Keep a plastic shovel designated for the deck — metal shovels will gouge wood and scratch composite surfaces. Always push snow with the grain of the deck boards. For ice, use calcium chloride or calcium magnesium acetate as a deicer — both are safe for wood and composite decking. Avoid rock salt entirely, as it damages wood fibers and voids warranties on composite products like Trex.

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