Anacortes Siding Flounder Bay sits on the west side of Anacortes, close enough to the water that homes there deal with a different set of conditions than a deck built farther inland in Skagit County. Salt-laden air, wind-driven rain, and a moss season that can stretch across most of the year all take a toll on exterior wood, and a deck — flat, exposed, and taking weather from every angle — usually shows that wear before anything else on the property does.
Composite decking is built to handle that kind of exposure better than wood, but the category covers a wide range of quality and construction. This page walks through what a Flounder Bay home actually needs from a composite deck, what a correct installation looks like out here, and why the details matter more on this stretch of Anacortes waterfront than they do on a typical inland lot.
What Flounder Bay's Climate Actually Does to a Deck
Salt Air and Corrosion
Homes close to the water in Flounder Bay catch salt-laden air off the Salish Sea more consistently than properties a few blocks inland. That salt exposure works on exposed metal continuously — fasteners, brackets, railing hardware — and corrosion often starts well before it's visible on the surface. A corroding fastener loses holding strength gradually, which is one reason fastener grade on a deck this close to the water isn't a place to save money.
Driving Rain
Anacortes gets its share of wind-driven rain, and a waterfront property like Flounder Bay tends to take it more directly than a sheltered inland lot. Rain that's being pushed sideways by wind finds its way into gaps and joints that straight-down rain wouldn't reach, which is why board spacing, drainage beneath the deck surface, and how the deck ties into the house at the ledger all matter as much as the decking material itself.
A Long Moss and Algae Season
The Pacific Northwest's damp stretch runs long, and shaded or north-facing sections of a deck — especially under mature trees, which are common around Flounder Bay — stay wet longer between dry spells. That moisture holds onto surfaces and gives moss, algae, and mildew a foothold. On wood decking, that means regular treatment and cleaning just to keep the surface from staining and going slick. On composite, how the board is built determines how much of that growth actually takes hold.
Mild but Real Freeze-Thaw
Anacortes doesn't see the harsh winters that inland or higher-elevation parts of the state do, but there are still enough freeze-thaw cycles each winter to matter. Moisture that's gotten into a joint, a fastener hole, or an uncapped board's core can expand when it freezes, and repeated cycles of that will loosen connections and open up cracking over several seasons. It's a slower failure mode than storm damage, but it's a steady one.
What "Composite Decking" Actually Means
Capped vs. Uncapped
Capped composite boards have a plastic shell wrapped around a wood-plastic composite core, which keeps moisture, staining, and organic growth from reaching the core material. Uncapped composite — the older style of the product — leaves that wood-plastic blend exposed on all sides, so it absorbs more moisture and is more prone to mold, staining, and surface wear. In a climate with as much sustained dampness as Skagit County's, that difference shows up faster than it would somewhere drier, which is why we standardize on capped composite for decks in this area.
Composite vs. PVC
Some manufacturers offer fully cellular PVC decking, with no wood fiber in the board at all. PVC resists moisture absorption completely, which sounds like an obvious win in a wet climate, but it can flex more under heavy point loads and generally costs more than a well-built capped composite. For most Flounder Bay decks, capped composite gets the moisture resistance that matters here without the added cost — but we'll go over both options against your specific site and budget rather than assume one is automatically right.
What a Correct Composite Deck Build Involves Here
The decking boards get most of the attention, but on a waterfront lot like this, the substructure and fastening details are what actually determine whether the deck holds up. A build done right for Flounder Bay conditions includes:
- Framing material suited to sustained moisture exposure — pressure-treated lumber rated for ground contact and dampness, not a general-purpose grade
- Stainless steel or coated coastal-grade fasteners throughout, since standard hardware corrodes faster this close to salt air
- Hidden fastener systems on the decking surface where the product allows, reducing exposed metal and giving water fewer places to sit
- Correct board gapping for expansion, contraction, and drainage — composite still moves seasonally, just differently than wood does
- Ledger board flashing and attachment done correctly where the deck ties into the house, since wind-driven rain finds poorly flashed connections first
- Joist spacing matched to the specific composite product's span rating rather than a generic wood-framing layout
- Ventilation and drainage beneath the deck so moisture doesn't sit against the framing through the wet months
- Shaded or low-airflow sections planned for with a board product that resists mold and mildew, not just one chosen for color
Skip any one of these and the deck usually still looks fine on day one. The problems — a soft spot in the framing, a loosening railing post, corrosion staining around a fastener — tend to show up two, five, or ten years in, once the wet seasons have had time to work on whatever wasn't done right.
How Our Process Works
We start with a site visit to look at what's actually there: existing framing condition on a replacement, how close the deck sits to the water, how much shade and tree cover it gets through the day, and where drainage around the site currently goes. From there we go over composite product options that fit the budget and how the deck will actually be used, whether that's a quiet spot to sit or space built around entertaining.
Permitting in the City of Anacortes generally follows standard residential deck requirements, with additional review possible depending on setback, elevation, or proximity to the water for a given lot. We handle that permitting process as part of the job. Once permitted, the build follows the sequence above — substructure first, built for this site's actual exposure, then the composite surface, railing, and any trim work. We finish with a walkthrough covering what maintenance the specific product you chose actually needs, which with a good capped composite is genuinely minimal, but not zero.
Composite Decking Compared to the Alternatives
| Material | How It Handles Salt Air, Rain & Moss | Maintenance | Typical Lifespan Here |
|---|---|---|---|
| Capped composite | Strong — cap layer resists moisture absorption, staining, and organic growth | Occasional washing; no sealing or staining | Long-term, backed by manufacturer warranty |
| Cellular PVC | Excellent — no wood fiber to absorb moisture or feed mildew growth | Occasional washing; no sealing or staining | Long-term, at a higher upfront cost |
| Uncapped composite | Moderate — absorbs moisture, more prone to mold and mildew in shaded areas | Periodic cleaning to manage staining and growth | Shorter than capped products in this climate |
| Pressure-treated wood | Weak against sustained dampness — needs regular treatment to resist moss and rot | Regular sealing, staining, and moss treatment | Shortest, with the most ongoing upkeep |
| Cedar | Naturally moisture-resistant, but still grays and takes on moss without upkeep | Periodic sealing or staining to maintain appearance and protection | Moderate if maintained; degrades faster if neglected |
What Composite Decking Still Needs From You
Composite decking is low-maintenance compared to wood, not maintenance-free, especially in a climate that stays damp for months at a time. A little routine care keeps a Flounder Bay deck performing the way it's supposed to:
- Rinse or wash the surface periodically, particularly shaded sections, to keep moss, algae, and organic debris from taking hold
- Keep the gaps between boards clear of leaves and needles so water and airflow can move through as the design intends
- Check railing posts and fasteners annually for early corrosion or loosening, especially after fall and winter storms
- Trim back trees or shrubs that keep sections of the deck shaded and damp longer than they need to be
- Address any substructure issues — soft framing, standing water underneath — right away, since that's structural, not cosmetic
Why It Matters That We Already Work Flounder Bay
A crew that mostly builds decks inland can still install composite decking competently, but a waterfront job in a neighborhood like Flounder Bay comes with variables that don't show up as often elsewhere in Skagit County — salt exposure that's more constant, driving rain that hits harder without the shelter of surrounding development, and shaded lots where moss and mildew get a real head start most of the year. Working this area regularly means we're not guessing at those conditions or learning them on your project. We know what fastener grade actually holds up here, what substructure detailing keeps moisture from becoming a structural problem, and which composite products genuinely resist growth and staining through a long Pacific Northwest wet season rather than just looking good in a showroom.
That familiarity also means a straighter conversation about what your deck actually needs versus what's just an upsell — whether that's a full substructure rebuild or a straightforward resurfacing on framing that's still sound.
Get a Straight Answer About Your Deck
Whether you're replacing a worn wood deck, building new, or just want an honest read on what composite decking would take on your Flounder Bay property, we're happy to walk the site with you and lay out the options plainly. Reach out below for a free, no-pressure estimate.