A wooden deck is a great spot to enjoy spring mornings, summer BBQs, and crisp autumn evenings. But once winter hits, that deck faces a lot—heavy snow, freezing rain, and cycles of freezing and thawing. Without proper care, it doesn’t take long before water gets into the wood and starts causing problems like fading, cracks, or worse, structural decay.
Ottawa winters can be punishing. Wood that isn’t sealed or protected ends up absorbing moisture that weakens it over time. Snow piled up for weeks or ice forming under planters can trap water right where damage starts. This article walks through how winter affects wood surfaces, offers guidance on choosing waterproofing products, and looks at smarter ways to prepare your deck for what’s ahead.
Understanding the Impact of Winter on Wooden Decks
When you leave a wooden deck unprotected through winter, moisture begins to seep in early, often before the first deep freeze. Wood is porous, so it takes in water like a sponge. That wouldn’t be a problem if it didn’t also expand and contract every time the weather flips from freezing to thawing. Over time, these shifts wear the wood down.
Here’s what might start to show up:
- Cracking from moisture expanding within the boards
- Warping or bowing from water getting in unevenly
- Mould or mildew under accumulated snow
- Loose nails or fasteners from movement in softened wood
- Splinters and rough surfaces where the wood has broken down
Ottawa’s freeze-thaw pattern makes all of that worse. One day your deck is frozen solid, and two days later, it’s wet and soft. Then back to frozen. These cycles accelerate wear and tear, especially if water gets trapped between the decking and joists or collects around the edges.
You may also notice dark streaks, patches where the finish has worn off, or soft spots near stairs or railings. These are signs the wood has already been compromised. The good news is that regular waterproofing makes the deck less likely to absorb moisture in the first place, protecting both looks and structure.
Choosing the Right Waterproofing Materials
Picking the right sealer or treatment goes a long way in protecting a wooden deck through the winter months. Not all products hold up well in Ottawa’s conditions, and some are better suited for the job than others. What you choose can depend on how old the deck is, the type of wood, and how exposed it is to wind and snow.
Here are a few common waterproofing options:
- Penetrating sealers: These soak into the wood and harden it from the inside out. They allow the wood to breathe, which helps reduce the risk of mould and mildew. They tend to have a natural appearance and won’t peel.
- Film-forming sealants: These sit on the surface of the deck, forming a clear barrier. They offer more visible protection but can wear down faster in high traffic areas. They work well when strong surface protection is your goal.
- Stains with water-repellent additives: These change the deck’s look while adding strong protection from moisture and sunlight. They’re especially helpful if you want to refresh the colour of the boards while sealing them.
If safety for pets, kids, or surrounding plants is a concern, look for low-VOC or plant-based products. They give off fewer harsh smells and are often safer to use in sealed or small garden areas. For Ottawa’s harsher winters, pick a product rated for long-term durability that also mentions resistance to ice melt and heavy snow exposure. A semi-transparent water-resistant stain often checks all the boxes visually and functionally.
Just remember, even tough products wear down eventually. Frequent exposure to tough weather means reapplication every couple of years—so investing in durable but eco-friendly choices makes a lot of sense for long-term care.
Step-By-Step Waterproofing Process
Getting your deck ready for winter starts with proper prep. Waterproofing isn’t something to rush through, especially with Ottawa’s weather being what it is by late September. At this point in the year, it’s smart to get on it before the first freeze. Here’s how to manage the job safely and get lasting results from your waterproofing product.
- Clean the surface: Remove all furniture, pots, and tools from the deck. Sweep away leaves and dirt, then scrub the surface with a deck cleaner to remove grime and mould. If you spot algae, use a cleaner meant for wood that also targets growth. Let your deck dry completely for at least 24 to 48 hours. Never coat damp wood as it can trap moisture underneath.
- Inspect for damage: Look for loose nails, warped boards, or signs of rotting. Fix anything damaged before applying waterproofing. Lightly test soft spots with a screwdriver—if it sinks in easily, the wood is likely too damaged and needs to be replaced.
- Sand the surface if needed: If your deck has old stain or the boards are really rough to the touch, light sanding will help smooth it out and helps the new waterproofing product absorb better. Don’t forget to clean up sanding dust afterward.
- Apply the product: Follow the directions on your chosen sealer or stain. Use a brush or roller for corners and tight areas. For flat spaces, a pad applicator or sprayer gives an even coat. Take your time and avoid doing the project during direct mid-day sunlight. Morning or late afternoon when the sun isn’t strong is best.
- Let it cure: Curing time is just as important as application. Most products need a full day or two to seal completely. During this window, keep pets off the surface and don’t place any furniture back. Let nature do its thing and hold off until the seal is fully dry to the touch.
- Clean your tools: Brushes or rollers used with water-based products only need soap and water. Oil-based products may need mineral spirits for proper cleanup. Keep wastewater out of drains or flower beds.
Winter Maintenance Tips That Make A Difference
Sealing the deck is step one. The rest of winter care helps keep that waterproofing effort working as long as possible.
Here are habits that help your deck last longer:
- Clear snow regularly: Use a plastic shovel and move with the direction of the boards to avoid scratches.
- Watch for ice: Frozen build-up loves to collect in corners and under steps. Use a pet-safe ice melt to help manage slick areas without ruining your deck.
- Wipe off puddles: On the warmer days when snow melts, brush aside any small pools of water. Standing water is a warning sign that your drainage may need checking later.
- Look closely at corners and steps: Snow builds up here more than other spots. Mark anything that looks soft or discoloured for attention next season.
Here’s a seasonal check-in outline:
- October: Seal the deck before the freeze hits
- Mid-winter: Take a stroll after a major snowstorm
- March: Look for signs of damage as snow melts
- April: Plan repairs early, before spring showers roll in
A homeowner in Orleans even shared that ignoring a mound of snow near their deck box caused a corner board to rot right through. Since then, keeping that area clear has saved them from bigger headaches.
Make Winter Enjoyable with a Well-Tended Deck
Once your deck is treated and cared for, Ottawa’s long winter doesn’t have to be a time to shut your outdoor space down completely. Instead of letting it sit unused, make that winter-proofed surface welcoming.
Decks with sealed wood resist fading and decay, keeping their strength and shape longer and leaving you with less work to do in spring. There’s something comforting about seeing a clean, snow-cleared deck out the window, ready for some winter greenery or even a heater for short warm-ups outdoors.
Winter care doesn’t take away from the joy your deck brings. It adds to it. Regular maintenance, like waterproofing and snow clearing, helps keep your outdoor space safer, stronger, and more beautiful. Whether it’s a coffee on a crisp morning or planning spring updates, your deck can be a spot to enjoy through every season in Ottawa.
Prepare your deck for each season with guidance from Capital Yardworks. If you’re thinking about adding function and style to your backyard, take a look at our work in outdoor carpentry in Ottawa. With the right care and upgrades, your deck can become a go-to spot no matter the season.
