Burlington Decking Built for Guemes Island's Marine Climate
Guemes Island sits out in the Salish Sea, and that location shapes everything about how a deck should be built and maintained there. Homes on or near the island deal with salt-laden air off the water, driving rain that comes in sideways during winter storms, and a long stretch of the year where shade, moisture, and cool temperatures combine to grow moss on almost any horizontal surface that isn't actively shedding water. A deck on Guemes Island isn't just an outdoor living space — it's a structure that has to shrug off conditions that would slowly wreck a poorly chosen material or a rushed installation.
Composite decking has become the standard recommendation for homeowners in this part of Skagit County precisely because it doesn't feed the problems the climate creates. It won't absorb moisture and swell, it doesn't offer the same foothold for mold and moss spores that raw wood grain does, and it holds up to salt exposure without the surface degradation you'll eventually see in untreated or under-maintained lumber. That said, composite decking is not maintenance-free or foolproof — it still has to be installed correctly for the specific site conditions on the island, and not every composite product or installation approach is equally suited to a marine environment.
What Salt Air and Driving Rain Actually Do to a Deck
It helps to understand the specific failure modes we're designing against, because they're different from what you'd worry about with a deck in a drier inland part of Washington.
Salt air and hardware corrosion
Salt in the air accelerates corrosion on any exposed metal — fasteners, joist hangers, post bases, and railing hardware. On a standard-grade fastener, that corrosion can start showing within a few seasons on a waterfront or near-waterfront property. This is less about the decking boards themselves and more about everything underneath and holding them together, which is why hardware selection matters as much as board selection on Guemes Island jobs.
Driving rain and water intrusion
Wind-driven rain doesn't fall straight down — it gets pushed sideways and upward under railings, around post connections, and into ledger board attachments at the house. If flashing, drainage, and board spacing aren't handled correctly, water finds its way into framing and into the house band joist behind the ledger, which is where you get rot that's invisible from the deck surface until it's a structural problem.
Moss, algae, and shaded surfaces
Guemes Island has plenty of tree cover and damp, mild winters, which is exactly what moss and algae need to establish on decking. Wood decking gives these organisms a rough, porous surface to grip. Composite boards, especially fully capped ones, offer less to hold onto and clean up far more easily — but moss can still grow on any decking material if a deck is deeply shaded and never dries out between rain events.
Comparing Decking Materials for an Island Property
We get asked regularly why we steer most Guemes Island clients toward composite over wood or higher-end PVC. Here's the honest breakdown of trade-offs, not a sales pitch for one product.
| Material | Salt/Moisture Behavior | Moss & Mold Resistance | Maintenance | Typical Lifespan |
|---|---|---|---|---|
| Pressure-treated wood | Absorbs moisture, prone to cupping and splitting near the water | Low — porous grain holds spores | Annual cleaning, periodic sealing/staining | 10-15 years with upkeep |
| Cedar | Naturally rot-resistant but still absorbs water over time | Moderate, drops off without maintenance | Regular sealing to keep resistance | 15-20 years with diligent care |
| Capped composite | Does not absorb water; shell resists staining | High — smooth cap sheds moss and algae | Occasional washing, no sealing/staining | 25-30 year warranties common |
| Uncapped/first-gen composite | Can absorb moisture at the core over time | Lower than capped products; more prone to surface mold | More frequent cleaning | Shorter service life, largely phased out |
| PVC/cellular decking | Fully water-resistant, will not absorb moisture | High | Low | Comparable to capped composite, higher upfront cost |
For most Guemes Island homes, fully capped composite hits the right balance of moisture performance, appearance, and cost. We'll talk through PVC as an option too, especially for decks with heavy sun and salt exposure where every bit of extra durability counts, but it's a real cost jump and not always necessary to get the performance a homeowner needs.
What a Correct Composite Deck Build Involves Here
The board itself is only part of the job. A composite deck that actually holds up on Guemes Island depends on decisions made before a single board is fastened down.
Substructure and hardware
We use corrosion-resistant fasteners and connectors rated for coastal exposure, not standard interior-grade hardware. Joist hangers, screws, and post hardware are chosen for the environment, not just the budget — this is one of the areas where cutting corners doesn't show up for a couple of years, then shows up all at once.
Drainage and ventilation underneath
Composite decking needs airflow beneath the boards to dry out properly between rain events. We plan joist spacing, board gapping, and any under-deck drainage systems so water sheds away from the structure instead of pooling against framing or hardware.
Ledger attachment and flashing
Where a deck attaches to the house, correct flashing is what keeps driving rain from working its way behind the ledger board and into the wall assembly. This is a detail that's easy to shortcut and expensive to fix later, so we treat it as non-negotiable on every attached deck we build.
Board orientation and hidden fastening
Hidden fastener systems keep the deck surface clean and reduce the number of exposed fastener heads that can corrode or create pathways for water. We also plan board runs to minimize butt joints in high-traffic or high-exposure areas.
Our Process for a Guemes Island Project
- On-site assessment. We look at sun exposure, tree cover, proximity to the water, existing structure condition, and drainage before recommending anything.
- Honest material recommendation. We'll tell you where a mid-tier capped composite is genuinely enough, and where the extra cost of PVC or a premium composite line is worth it for your specific site.
- Written estimate. Clear scope, materials, and price before any work starts — no surprise add-ons partway through.
- Scheduling around ferry logistics. Guemes Island is ferry-access only from Anacortes, so we plan crew and material delivery schedules around the ferry timetable to keep the job moving efficiently rather than losing time to missed sailings.
- Demo and structural prep, including addressing any rot or hardware issues in the existing substructure before new decking goes down.
- Installation, following manufacturer spacing and fastening specs exactly, since that's what keeps a warranty valid and the deck performing as designed.
- Final walkthrough, where we go over care, cleaning, and what to watch for so you're not guessing at maintenance later.
Living With a Composite Deck on Guemes Island
Composite decking cuts down maintenance dramatically compared to wood, but "low-maintenance" isn't "no-maintenance," especially in a moss-prone, salty environment.
- Rinse or sweep debris off the deck regularly, especially in fall when leaf litter and organic matter build up fast under tree cover.
- Wash the surface a couple of times a year with a soft-bristle brush and a composite-safe cleaner to keep moss and algae from getting a foothold in shaded areas.
- Avoid pressure washing at close range or high pressure — it can damage the cap layer on composite boards over time.
- Check railing posts and hardware periodically for early signs of corrosion, since hardware is more vulnerable than the boards themselves in salt air.
- Keep gutters and downspouts near the deck clear so roof runoff isn't dumping extra water onto or under the deck structure.
- Trim back overhanging branches where practical to cut down on shade and debris that both encourage moss growth.
Why a Crew That Already Works Guemes Island Matters
Building on an island changes the logistics of a project in ways that don't apply to a mainland job in Burlington or the rest of Skagit County. Every delivery, every crew trip, and every follow-up visit runs on the ferry schedule, which means a contractor unfamiliar with that rhythm can turn a straightforward job into a drawn-out one through poor planning alone. A crew that regularly works the island already accounts for this — materials get staged and timed correctly, and crew days are planned to make the most of ferry access instead of fighting it.
There's also a practical-experience side to it. A contractor who has built and later serviced decks on Guemes Island has seen firsthand how different hardware, fastening systems, and even board colors hold up after a few years of real salt air and winter storms — not just what a spec sheet promises. That kind of feedback loop, from install to years of exposure, is what separates a deck that still looks and performs well after a decade from one that starts showing problems in year three.
Getting Started
If you're planning a new composite deck or replacing an aging wood deck on Guemes Island, we're happy to come take a look, walk the site with you, and put together a straightforward estimate — no pressure, no pushy sales tactics, just an honest read on what your property needs. Use the form below to request a free estimate and we'll get in touch to schedule a time that works with your island logistics.