What's the difference between composite decking and PVC decking?

Composite decking is made from a blend of wood fiber and plastic, often with a protective cap layer, while PVC decking is 100% synthetic plastic with no wood content. PVC tends to resist moisture slightly better and weighs less, while composite generally has a more natural wood-like look and feel. Both can perform well in a salt-air climate when installed with proper flashing and corrosion-resistant hardware.

How do I vet a contractor for a composite deck build on Lummi Island?

Ask specifically about their experience with island logistics — ferry-dependent material delivery and scheduling — since that affects both cost and timeline. Ask what fastener and hardware grade they use for salt-air exposure, and get specifics on ledger flashing rather than a vague answer. A contractor who can speak plainly about these details, rather than just naming a board brand, is usually the safer bet.

Does it matter which composite decking brand I choose?

The brand matters less than the board type — whether it's capped or uncapped composite — and how the substructure underneath is built. Most major composite manufacturers offer comparable capped products with similar warranty structures, so we help homeowners compare based on color, cost, and warranty terms rather than brand reputation alone. We're happy to walk through the specific product lines available for your project.

Do composite boards come with a warranty against fading or staining?

Most capped composite products carry a manufacturer warranty covering structural integrity and, separately, fading or staining, typically with different terms and lengths for each. Warranty coverage varies significantly by product line and is worth reading carefully before choosing a board, since coverage on lower-cost or uncapped products is often more limited. We can go over the warranty details for any product we're recommending before you commit.

Is composite decking worth it for a shaded, wooded Lummi Island lot?

Shaded, wooded lots hold moisture longer and are more prone to moss and algae, which makes composite's rot resistance especially useful in that setting. That said, no material eliminates the need for periodic cleaning in a shaded spot — composite just reduces the consequences of moisture sitting on the surface longer between cleanings. We can assess your specific lot's sun and shade pattern before recommending a board and finish.

Composite Decking for Lummi Island's Salt Air Climate

Building Decks for an Island Climate

Lummi Island sits out in Bellingham Bay, and that location changes what a deck has to survive. Homes here deal with a level of salt exposure, wind-driven rain, and shaded moisture that most inland Whatcom County properties never see. A deck built with mainland assumptions — standard fasteners, no salt-air-rated hardware, minimal drainage planning — tends to show its age fast on the island. Composite decking, installed correctly for this environment, is one of the more sensible answers to that problem, but "composite decking" covers a wide range of products and installation approaches, and not all of them hold up the same way out here.

This page is about composite decking specifically for Lummi Island homes: what the local climate actually does to a deck, what a correctly built composite deck looks like in this setting, and how our process accounts for the realities of working on an island.

What Salt Air, Rain, and Moss Actually Do to a Deck

It helps to be specific about the forces at work, because they don't all attack a deck the same way.

Salt Air and Corrosion

Airborne salt from the surrounding water settles on every exposed surface, including the deck itself and everything holding it together. The boards may be unaffected, but standard steel fasteners, brackets, and ledger hardware corrode faster near the water than they would a few miles inland. Corrosion at a ledger connection or a joist hanger is a structural issue, not a cosmetic one.

Driving Rain

Storms coming off the water tend to arrive with wind behind them, which pushes rain sideways into ledger boards, fascia, and any gaps in flashing. A deck built without proper ledger flashing and a slight drainage slope will trap water against the house rather than shedding it.

Moss and Shade

Whatcom County's long wet season, combined with tree cover common on wooded island lots, keeps many deck surfaces damp for extended stretches. Moss and algae need exactly that — shade and moisture — and they'll colonize any surface that stays damp long enough, composite or wood. The difference is how easily the surface sheds that growth and how much damage it does while it's there.

Why Composite Makes Sense Here — With Caveats

Composite decking's main advantage in this climate is that the boards themselves don't rot, splinter, or need annual staining. A quality capped composite board resists moisture absorption far better than wood, which matters when a deck is wet more often than it's dry for several months of the year. That said, composite isn't maintenance-free, and it isn't immune to the climate — it just fails differently than wood does, usually more slowly and more predictably.

Where Composite Still Needs Attention

Moss and algae will still grow on composite surfaces that stay shaded and damp — the boards need periodic cleaning, not zero cleaning.
Uncapped or older-generation composite boards can absorb some moisture at cut ends and fastener points if those areas aren't properly sealed or protected during installation.
Color and finish vary by manufacturer — lighter colors show pollen and organic buildup faster; darker colors show less growth but run hotter in direct sun.
The substructure underneath (joists, ledger, flashing, fasteners) does not become salt-air resistant just because the boards on top are composite — it has to be specified and built for that separately.

Capped vs. Uncapped Composite: Why It Matters More Near Water

Composite boards generally fall into two categories, and the difference matters more on Lummi Island than it does inland.

Capped Composite

These boards have a polymer shell wrapped around a wood-plastic composite core. The cap is what actually resists moisture, staining, and surface wear. In a salt-air, high-rain environment, that outer cap is doing most of the work of keeping moisture out of the core, so it's worth prioritizing on an island property.

Uncapped Composite

Older or budget composite products expose the wood-plastic core directly. They can still perform reasonably well inland, but on a property with this much moisture exposure, an uncapped product is more likely to show fading, staining, and surface roughening sooner. We're upfront with clients about this trade-off rather than installing a lower-cost product and letting the climate expose the difference in a few years.

The Substructure Is Where Decks Actually Fail

Most deck failures we see, on the island or anywhere in the county, start below the boards, not in them. On a salt-air property, three things get extra attention:

Ledger Flashing

The connection where the deck meets the house is the single most common point of water intrusion into a structure. Correct flashing — installed in the right order relative to the house's siding or trim — keeps wind-driven rain from tracking behind the ledger and into the wall framing.

Fasteners and Hardware

Near the water, we specify stainless steel or marine-rated coated fasteners and hardware for structural connections, not standard galvanized hardware that's adequate inland but corrodes faster here. This is a small cost difference at build time and a significant difference in how the deck holds up over 10-15 years.

Joist Protection and Drainage

Joist tape or an equivalent moisture barrier over the top of the joists keeps rain that gets between the boards from soaking directly into the framing lumber. Combined with a proper slope away from the house, this keeps water moving off the deck instead of sitting on the structure.

How We Approach a Lummi Island Composite Deck

Site visit and assessment — we look at sun/shade exposure, prevailing wind and rain direction, tree cover, and the existing structure if we're replacing a deck.
Board and hardware selection — matched to how exposed the site is, not a one-size-fits-all spec.
Framing and flashing — ledger flashing, joist protection, and corrosion-resistant hardware built in from the start.
Composite board installation — proper spacing for drainage and expansion, hidden or manufacturer-approved fastening systems, clean end cuts.
Final walkthrough — we go over basic care so the deck actually gets the lifespan it's built for.

Comparing Decking Materials for This Climate

Factor	Capped Composite	Pressure-Treated Wood	PVC Decking
Salt air / moisture resistance	Strong	Moderate, needs sealing	Very strong
Annual maintenance	Periodic cleaning	Staining/sealing, regular inspection	Periodic cleaning
Moss/algae resistance	Moderate — needs cleaning	Low, absorbs moisture	Moderate to high
Upfront cost	Mid to upper	Lower	Highest
Typical lifespan with proper install	25-30+ years	10-15 years before major repair	25-30+ years

Every material on this table can work on Lummi Island if it's specified and installed correctly for the site. Composite tends to be the best balance of upfront cost, appearance, and long-term durability for most homeowners here, which is why it's what we install most often — but we'll walk through the honest trade-offs for your specific lot before recommending anything.

Living With the Moss Season: Realistic Maintenance

No decking material on Lummi Island is truly maintenance-free once you factor in the region's long wet season. What composite buys you is less maintenance and less consequence when maintenance slips. A composite deck that goes uncleaned for a season will look dull and may develop some moss in shaded corners — it won't rot, cup, or splinter the way an unsealed wood deck can. Basic seasonal care is enough to keep it in good shape:

Sweep off leaves, needles, and debris regularly, especially in fall and through the wet months.
Rinse the surface periodically to clear salt film and organic buildup before it sets in.
Clean shaded, damp corners more often — that's where moss and algae take hold first.
Check the gaps between boards once or twice a year to make sure drainage paths aren't clogged with debris.
Have the substructure and ledger connection inspected every few years, even though the boards themselves need little attention.

Why a Crew That Knows Lummi Island Matters

Lummi Island is only reachable by ferry, which changes how a project has to be planned. Materials, equipment, and crew all need to be scheduled around ferry availability, and a contractor who hasn't accounted for that ahead of time can turn a straightforward deck build into a series of delays. We plan Lummi Island jobs with that logistics reality built in from the start — material orders staged in advance, crew time scheduled efficiently around ferry runs, and a realistic timeline given to the homeowner up front instead of one that assumes mainland conditions.

Beyond logistics, working this stretch of Whatcom County regularly means we've seen firsthand how salt air and shade affect decks built with different levels of care, which shapes what we recommend and what we won't cut corners on.

Signs Your Current Deck May Need Replacing

Soft, spongy, or visibly rotted boards, especially near the ledger or in shaded areas.
Rust staining around fasteners or visible corrosion on brackets and hangers.
Persistent moss or algae that returns quickly after cleaning.
Gaps, cupping, or splintering boards that have gotten worse over the past year or two.
Water pooling on the surface instead of draining off.
Any looseness or movement where the deck connects to the house.

If any of these sound familiar, it's worth having the deck looked at before it becomes a safety issue rather than a maintenance one.

If you're planning a new composite deck or replacing one that hasn't held up to Lummi Island's climate, we're happy to take a look and give you a straightforward, no-pressure estimate. Fill out the form below and we'll follow up to schedule a visit.