Ferndale Window Decking Built for the Marietta Waterfront, Not a Catalog Photo
Marietta sits close to the water outside Ferndale, and that changes what a deck has to survive. A composite deck built to a generic spec sheet from a big-box store often struggles here in ways it wouldn't twenty miles inland. Salt-laden air corrodes hardware faster, driving rain finds gaps that would stay dry in a drier climate, and a long, damp moss season turns any deck with poor drainage into a slick, green liability by late winter. We build decks in this area specifically, and the details we pay attention to reflect that.
This page covers composite decking as it applies to homes in and around Marietta: what the local climate actually does to a deck over time, what a correct installation looks like, how our process works, and why hiring a crew that already works this stretch of Whatcom County matters more than it might seem.
What Salt Air, Rain, and Moss Actually Do to a Deck
Salt Air and Hardware
Homes near the water in Marietta deal with airborne salt that settles on every exposed surface, including deck fasteners, railing brackets, and structural hardware. Standard zinc-coated screws and brackets corrode noticeably faster in this environment than they do a few miles inland. Once a fastener starts to rust, it weakens, stains the surrounding decking, and eventually needs to be replaced — often before the boards themselves show any wear.
Driving Rain and Moisture Intrusion
Whatcom County doesn't just get a lot of rain — it gets a lot of wind-driven rain, which pushes moisture sideways into ledger connections, under railing posts, and into any seam that isn't properly flashed or sealed. A deck that's watertight on a calm day can still leak where it attaches to the house if the flashing detail was skipped or done wrong. That's usually where rot shows up first, hidden behind the decking where nobody sees it until it's a real problem.
Moss, Algae, and Surface Traction
Between fall and spring, low sun angles and near-constant damp keep shaded deck surfaces wet for days at a time. That's exactly the environment moss and algae need to take hold. Beyond the appearance issue, a mossy deck surface gets genuinely slippery, and moss holds moisture against the board surface longer than it would otherwise sit there. Drainage, airflow underneath the deck, and board surface texture all affect how much of a moss problem a given deck ends up with.
Why Composite Decking Fits This Climate
Composite decking doesn't rot, doesn't need annual staining, and doesn't splinter the way wood does after a few damp winters. For a lot of Marietta homeowners, that's the whole appeal — less upkeep, more consistent appearance year over year. But composite isn't maintenance-free, and it isn't immune to problems if it's installed wrong. It handles moisture differently than wood: it doesn't absorb water into the board itself the way untreated lumber does, but it can still trap moisture underneath or between boards if the substructure and spacing aren't right, which is where mold and mildew on the surface usually come from.
The material itself is generally a wood-plastic composite, either capped (a plastic shell over the composite core) or uncapped. Capped boards resist moisture, staining, and fading noticeably better and are what we recommend for anything near the water. Uncapped composite is less expensive but absorbs more moisture at the core over time and is more prone to surface mold in a shaded, damp spot — a real consideration in a climate that stays wet as long as this one does.
What a Correct Composite Deck Installation Involves
Substructure and Drainage
The framing underneath a composite deck matters as much as the boards on top. Joists need to be spaced correctly for the specific composite product being used — composite has different span and support requirements than wood, and following the manufacturer's spacing is what keeps the deck from flexing or sagging over time. We also grade and detail the substructure so water sheds away instead of pooling under the deck, which matters in a climate where the ground rarely gets a chance to fully dry out.
Flashing Where the Deck Meets the House
The ledger board connection — where the deck attaches to the house — is the single most common place decks leak and eventually fail. Proper flashing here, installed correctly against the siding and sealed at every penetration, is non-negotiable on a job in this climate. It's also the detail that's easiest to rush or skip, and the one that causes the most expensive repairs down the line when it's done wrong.
Fastening and Hardware
Given the salt air, we use corrosion-resistant, marine-grade fasteners and structural hardware rated for coastal exposure rather than standard-grade hardware. It costs a little more up front and saves a homeowner from dealing with rust streaks and failing brackets a few years in.
Board Spacing and Fastening Pattern
Composite boards expand and contract with temperature more than wood does, so gap spacing between boards has to account for that movement — too tight and boards can buckle, too loose and the deck looks and feels sloppy. Hidden fastener systems, used correctly, also affect how well water sheds off the surface versus sitting in a screw head.
Composite Decking: Cost and Performance Comparison
Composite decking comes in a range of grades, and the differences matter more in a wet, salt-exposed climate than they would somewhere drier. Actual installed cost depends on deck size, substructure condition, railing choice, and site access, but the table below outlines the general trade-offs by tier.
| Decking Type | Moisture Resistance | Typical Maintenance | General Cost Range |
|---|---|---|---|
| Uncapped composite | Moderate — core can absorb moisture over time | Occasional cleaning; watch for surface mold in shaded areas | Lower end of composite pricing |
| Capped composite (standard) | Good — plastic shell resists moisture and staining | Periodic washing; low overall upkeep | Mid-range |
| Capped composite (premium) | Very good — enhanced fade and stain resistance, denser core | Minimal; longer warranty coverage | Higher end, reflects longer expected service life |
| Pressure-treated wood | Depends entirely on maintenance and sealing schedule | Annual cleaning and re-sealing to prevent rot | Lowest material cost, higher long-term labor cost |
For most homes in Marietta, we point people toward capped composite for anything with real sun and rain exposure, and reserve uncapped composite for covered or low-exposure areas like a shaded porch deck where moisture pooling is less of a factor.
Our Process, Start to Finish
We keep the process straightforward and transparent from the first visit to the final walkthrough:
- On-site assessment — we look at the existing structure (if there is one), drainage, sun and rain exposure, and how the space will actually be used.
- Written estimate — clear scope, materials, and pricing before any work starts, no surprise add-ons.
- Permitting — we handle the local permitting requirements for the job so the homeowner doesn't have to chase it down.
- Demolition and substructure work — removing any failing old decking and correcting framing, ledger flashing, and drainage issues before a single new board goes down.
- Composite installation — proper spacing, fastening, and hardware suited to a marine climate.
- Final walkthrough — we go over the finished deck together and cover basic care before we consider the job done.
Maintenance: What Marietta Deck Owners Actually Need to Do
Composite decking is low-maintenance, not no-maintenance — especially in a climate with a real moss season. A little regular care keeps it looking right and prevents small issues from becoming bigger ones:
- Sweep off leaves, needles, and debris regularly, especially in shaded corners where moisture lingers
- Wash the surface once or twice a year with a soft-bristle brush and a composite-safe cleaner to prevent moss and algae buildup
- Keep gutters and downspouts clear so runoff doesn't pour directly onto or under the deck
- Check railing hardware and fasteners periodically for early signs of corrosion, particularly closer to the water
- Make sure under-deck airflow isn't blocked by stored items, planters, or debris buildup
- Avoid pressure-washing at high pressure directly into board seams, which can drive water into the substructure
Why Hiring a Crew That Already Works Marietta Matters
A lot of what makes a deck last here isn't visible once the job is finished — it's in the flashing detail behind the ledger, the hardware grade chosen for salt exposure, and the drainage plan under the boards. Those are the things a crew learns by building decks in this specific climate repeatedly, not by following a generic national spec sheet. A contractor who already understands what Whatcom County's rain and moss season does to a deck over five or ten years builds differently from the start, rather than fixing it later.
We're a Ferndale-based crew, and Marietta is part of the area we regularly work in. That means we're not guessing at what the coastal exposure here requires — we've already seen how different hardware, board types, and drainage details hold up over time on homes nearby.
If you're considering a new composite deck or replacing one that's not holding up to the weather, we're happy to take a look and put together a free, no-pressure estimate. Use the form below to get in touch and we'll go from there.