Anacortes Roofing Decking Built for March Point's Marine Exposure
March Point sits out along the water in Skagit County, which means homes here take a different kind of weather beating than a deck inland in Mount Vernon or Sedro-Woolley might see. Wind off the bay carries salt. Rain doesn't just fall here, it drives sideways into railings, ledger boards, and fastener heads. And with tree cover, shade pockets, and long damp stretches through fall and winter, moss gets a running start on any surface that can't shed water and dry out between storms. A deck built without those specifics in mind will show it within a few seasons — not because the material failed outright, but because the install didn't account for how this particular stretch of coastline actually behaves.
Composite decking can handle this environment well, but only when it's installed correctly for it. This page covers what March Point homes need from a composite deck, what a correct installation actually involves, and how we approach the work.
What the Climate Actually Does to a Deck
Salt Air and Hardware Corrosion
Salt-laden air off Fidalgo and Padilla Bay accelerates corrosion on anything metal — fastener heads, hidden clip systems, railing brackets, post connectors. Standard coated screws can start pitting years before they should. This matters more for the framing and hardware than for the decking surface itself, since a corroded fastener under a perfectly good composite board is still a structural problem waiting to surface.
Driving Rain and Trapped Moisture
Wind-driven rain finds its way into places vertical rain never would — under board edges, into fastener holes, behind ledger boards where a deck attaches to the house. Composite boards themselves don't absorb and rot the way wood does, but the framing underneath still can if water gets trapped there with no way to drain or dry.
The Long Moss Season
Shaded or north-facing decks, or ones tucked near trees and shrubs, can stay damp for weeks at a stretch through the wetter months. Moss and algae take hold in board grooves, in the gaps between boards, and anywhere debris sits and holds moisture. Beyond looking bad, a mossy deck surface gets slick and genuinely dangerous underfoot.
Why Composite Decking Fits This Environment
Composite decking doesn't rot, splinter, or need annual staining the way wood does, which is a real advantage in a climate that gives wood decking very little time to dry out between rain events. Capped composite and PVC boards resist moisture absorption at the surface, which limits the swelling, checking, and soft spots that show up on wood over time.
That said, "low maintenance" isn't the same as "no maintenance," and it isn't the same as "install it any way and it'll be fine." Composite still needs airflow underneath, correct slope, and periodic cleaning to keep moss and mildew from staining the surface texture — especially on wood-grain embossed boards, where the grooves in the pattern can hold organic debris just like real wood grain would.
Composite Decking Options
Not all composite board is built the same, and the right choice for a waterside March Point lot isn't always the cheapest option per square foot. Here's how the main categories compare for this kind of exposure:
| Board Type | Moisture Resistance | Typical Look | Maintenance |
|---|---|---|---|
| Capped Composite | High — protective cap over a composite core | Wood-grain, wide color range | Occasional wash; good balance of cost and durability |
| PVC / Fully Cellular | Highest — no wood fiber in the board | Cleaner, more uniform | Least prone to staining or moss buildup |
| Uncapped / Mineral Composite | Lower — exposed core absorbs surface moisture over time | Wood-grain, often more affordable | More prone to mildew staining in a constant-damp climate |
For most March Point homes we recommend capped composite as the practical middle ground, with PVC as an upgrade for decks in heavier shade or closer to the water where moisture exposure is greatest. As a matter of our own standard, we steer clients away from uncapped composite on waterside lots in this area — not because the product is defective, but because an exposed core simply doesn't hold up as well against years of driving rain and limited drying time, and we'd rather set that expectation up front than have a homeowner discover it themselves in year four.
A Practical Checklist for Choosing Boards
- Fully capped on all four sides, not just the top face
- Manufacturer-rated for coastal or high-moisture environments
- A grooved-edge profile compatible with hidden fastener clips
- A warranty that explicitly covers stain and mold resistance, not just structural failure
- A color and texture you're comfortable maintaining — lighter colors show pollen and organic staining faster than mid-tones
What a Correct Installation Involves
Substructure and Ventilation
The framing underneath a composite deck matters as much as the boards on top. Joist spacing needs to match the manufacturer's span tables — typically tighter for diagonal or picture-frame board patterns than for straight runs — and joist tops should carry a protective flashing tape to keep water from soaking into the framing through screw penetrations. Airflow underneath the deck is what lets everything dry out between storms instead of staying wet for days.
Fastening and Spacing
Hidden fastener clip systems give a cleaner look than face screws and keep fastener heads out of standing water, but they need to be installed with the gapping the manufacturer specifies so boards can expand and contract through temperature swings without buckling. In a salt-air environment, hardware rated for corrosion resistance is worth the upgrade over standard coated fasteners.
Drainage and Flashing
A deck needs a slight slope away from the house — roughly an eighth of an inch per foot — so water actually runs off instead of pooling. Where the deck ties into the house at the ledger board, flashing has to be detailed correctly to keep driving rain from working its way behind the siding and into the wall assembly. This is one of the most common places we find problems on existing decks in this area, and it's invisible until something goes wrong.
How We Approach a March Point Deck Project
We start with a site visit that looks at sun and shade patterns, wind exposure, and the condition of any existing structure. On older decks, or ones that were built or added onto without a permit, we often find framing that's undersized, poorly flashed at the ledger, or already showing rot damage hidden under the old decking surface — problems that need addressing before new composite boards go down, not after.
From there we plan board layout, fastening system, slope, and ledger flashing before any material gets ordered. Installation follows manufacturer specifications for span, gapping, and fastening, and we finish with a walkthrough covering how to care for the deck through its first wet season here.
Keeping Moss and Mildew From Taking Over
- Sweep leaves and needles off the deck promptly — trapped organic debris is what feeds moss growth
- Clear debris from the gaps between boards and at the perimeter so water can keep draining
- Keep nearby shrubs and low branches trimmed back to improve airflow and sun exposure
- Wash the surface once or twice a year with mild soap and water, or a manufacturer-approved cleaner
- Avoid pressure washing at close range or high PSI, which can damage the board's protective cap
- Check fastener heads and railing hardware periodically for early signs of corrosion
What Affects Cost
Composite decking is a bigger upfront investment than pressure-treated wood, but it avoids the recurring cost of sanding, staining, and board replacement over time. Rough installed pricing in this area generally runs somewhere in the $35–$70+ per square foot range, with the spread driven by the factors below rather than any single price per board.
| Factor | Why It Matters |
|---|---|
| Board tier (capped vs. PVC vs. mineral composite) | Material cost and moisture performance vary significantly by tier |
| Substructure condition | Replacing rotted or undersized framing adds cost but is not optional if found |
| Deck size and layout | Diagonal patterns, curves, and multiple levels add labor and material |
| Railing type | Composite, aluminum, and cable railing carry very different price points |
| Site access | Waterside or sloped lots can complicate material staging and equipment access |
Why a Crew That Already Works March Point Matters
A contractor who works this specific area regularly already knows how the wind and rain move off the water here, which lots hold shade and moss longer than others, and what Skagit County permitting looks like for attached and standalone decks. That familiarity matters when it comes to spotting the framing problems that years of driving rain tend to hide under old decking, and it matters when deciding where to spend a little more on hardware or board tier versus where standard specs are genuinely fine. A crew learning this coastline for the first time on your project is learning it at your expense.
If you're considering a new composite deck or replacing an aging one in March Point, we're happy to take a look and walk you through what your specific site needs. Reach out for a free, no-pressure estimate — the form below is the fastest way to get started.