More than half of my career has been spent working in the Pacific Northwest. When it rains for nearly 9 months continuously, the sunny respite of summer pulls everyone outdoors onto porches, decks, and patios to celebrate. Since rain and cold weather can be damaging to a deck, my clients typically hire me during the drier seasons to help with clean-up and new deck installation.
I’m consistently looking to give my clients more value, and over the years, I’ve done some experimenting with materials to find the ones that work best for every climate. As it turns out, building a long-lasting, beautiful and low-maintenance deck for a rainy climate means moving away from wood. Below, we’ll explore the best decking materials for Seattle, Portland and the Pacific Northwest.
Finding Materials That Will Survive Months of Rain
It probably goes without saying that the levels of precipitation out in the Pacific NW can be epic and downright depressing sometimes. And while people can take shelter from the continuous rainfall, decks and outdoor structures don’t have that luxury. Understanding why rain causes such a problem for decks can help when it comes to choosing a decking material.
- Moisture Infiltrates and Deteriorates Boards: Water will always find the lowest level and the path of least resistance. That means that horizontal surfaces like decking boards are especially vulnerable to water erosion and penetration. Unprotected wood will soak up water like a sponge, channeling the moisture through the board’s paths of least resistance until it pools, saturates, and expands the wood. This action, paired with periods of drying out in the sun, leads to cracks and warping in the wood or decking material. It can also lead to swelling and shrinking that forces nails and screws out of the decking boards.
- Different Materials Require Different Methods: The two main choices in decking are wood and composite. Both types need to be protected from extended, heavy rain. Here’s how.
- Wood: Whether it’s cedar decking or Brazilian ipe, wood decks require a sealer or an oil to form a thick enough layer to repel water. Some sealers are more durable and long lasting than others. On average, though, most decks could use a reapplication of sealer about every two years. In the Pacific Northwest, this is usually sufficient, but doing it once a year is usually even better.
- Composite Decking: For a while, composite was not a good choice in my area. In the first generations of composite decking, water would find its way into the board (made of a combination of plastic and sawdust), leading to the same kind of deterioration experienced by wood. These boards tended to swell, chip, crumble, and mold. In short order, though, composites underwent a revolution. Most now have a full cap--a tough waterproof coating that completely encases the composite board below. If using composite decking, I always advise getting boards with this kind of protection. And even fully capped decking isn’t all the same. Some composites are made with a combination of plastic and bamboo flour, rather than sawdust, which makes the core of the boards much more moisture resistant than typical composites.
The Best Decking Material for Seattle and the Pacific Northwest
After the challenge of moisture is addressed, there are a couple qualities that make life far easier for those with Seattle and NW decks:
- Easy Cleanup to Enjoy the Sunny Months: When spring and summer do arrive, Seattleites want their decks to be usable with as little fussing with cleanup as possible. While cleanup requirements will differ from location to location, wood and composite have consistent needs when it comes to getting them ready for the season.
- Wood: When the seal is strong and fresh, wooden decking cleans up very easily. Once the protection wears down, though, the porous surface of the wood attracts dirt, mold, and mildew. Clean-up usually requires pressure washing, sanding, and then a reapplication of sealer.
- Composite: Clean-up of composite decking is typically as easy as a mopping session or a quick hosing off. Since the capping isn’t as porous as wood, dirt and other detritus don’t collect as easily, and mold and mildew are rare and easy to rinse off.
- A Combination of Style and Durability: High-quality composite does very well in rainy climates, but all the functionality and durability in the world won’t matter if the material is ugly. Luckily, there is now composite decking that looks like wood, including ipe and other hardwoods, but without the maintenance load.
I’ve put in dozens of decks in the Pacific Northwest, particularly around Seattle, and I’ve maintained and repaired even more. As my skills have grown, I’ve learned to accomplish more with less effort and expense. While I still install plenty of cedar and ipe decks, many of my clients want to spend more time enjoying their decks instead of working on them. I almost always steer these clients in the direction of high-quality, fully capped composite decking.
There are a few types of composites out there, but the first product I usually suggest they consider is the bamboo composite Infinity® I-Series composite decking produced by Fortress Building Products. It’s all the things high-quality decking should be--beautiful, realistic, tough against sun, rain, and mold, elegant, safe, and barefoot friendly. When clients’ deck projects get bigger, and require a railing or structure like a pergola, I usually suggest looking at Fortress®' full line of building materials. The other Fortress products I’ve worked with – like railing, fencing or framing - are just as sturdy, unique, and well-made as their decking.