How is composite decking installation different from a standard wood deck build?

The boards themselves install differently — composite uses hidden fastener systems and requires expansion gaps that wood doesn't — but the bigger difference is in the substructure. Because composite is meant to last decades without staining or sealing, the flashing, joist protection, and drainage underneath have to be done right the first time, since you won't be pulling boards to fix a hidden problem later the way you might with a wood deck repair.

What should I ask a contractor before hiring them for a composite deck?

Ask how they handle ledger flashing and joist protection, not just what board brand they carry — the substructure work is what determines whether the deck holds up. Also ask whether they're licensed and insured, whether they pull the required permit, and whether they've built decks in your specific area recently, since local conditions affect material and fastener choices.

Are all composite decking brands basically the same?

No. The biggest functional difference is capped versus uncapped composite — capped boards have a polymer shell that fully encloses the core, while uncapped boards expose the wood-plastic material at the surface. In a wet climate, that difference significantly affects how much the board absorbs moisture, stains, and grows mildew over time, so it matters more than brand name alone.

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

Capped composite has a wood-plastic composite core wrapped in a protective polymer shell, while PVC decking is cellular plastic all the way through with no wood content. PVC is essentially waterproof and slightly more resistant to moisture over time, but it costs more and can run hotter underfoot in direct sun, while capped composite offers very similar low-maintenance performance at a lower price point.

Does Custer's coastal location actually make a difference in how a deck should be built compared to further inland?

Yes — the salt air here accelerates corrosion on standard fasteners and metal hardware, so corrosion-resistant, composite-rated screws and connectors matter more than they would inland. Combined with the area's rainfall and long moss season, proper drainage, airflow underneath the deck, and capped composite boards all matter more here than they would in a drier, less coastal part of the county.

Expert Composite Decking for Custer Homes

Why Decking in Custer Takes a Different Approach

Custer sits close enough to the water that salt air is a constant factor in how outdoor materials age, and it gets the same driving rain and long gray stretches that define the rest of Whatcom County's exterior season. A deck built here isn't just furniture for the backyard — it's a structure that spends most of the year wet, shaded part of the day by evergreens, and exposed to airborne salt that corrodes fasteners and finishes faster than it would inland. Add in a moss season that can run from fall through spring, and you've got a surface that needs to shed water, resist organic growth, and hold its hardware without babysitting.

Composite decking earns its keep in this environment specifically because it doesn't absorb water the way wood does, doesn't need annual staining, and — when installed correctly — gives moss and algae a much harder surface to colonize. But "composite decking" covers a wide range of products and installation quality, and the difference between a deck that looks good for fifteen years and one that cups, mildews, or loosens at the fasteners within three usually comes down to what's underneath the boards, not the boards themselves.

What a Correct Composite Deck Build Involves

Composite boards are only as good as the frame and detailing beneath them. This is where most of the long-term problems we get called out for actually originate — not with the decking material itself.

Substructure and Ledger Flashing

Any deck attached to the house needs a ledger board that's properly flashed to keep water from working its way behind the siding and into the wall framing. In a climate that sees as much driving rain as this one, a poorly flashed ledger is one of the most common sources of hidden rot we find on older decks — often long before the decking itself shows any wear. Joists should be either naturally rot-resistant lumber or pressure-treated and capped with a joist tape or flashing membrane, since composite boards themselves shed water but the framing underneath still needs its own protection.

Fasteners and Board Spacing

Hidden fastener systems and stainless or coated composite-rated screws matter more here than in a drier climate — cheap fasteners corrode faster in salt air, and corroded fasteners are what cause boards to work loose or streak with rust stains over time. Board spacing also needs to account for the material's expansion and contraction, which is more pronounced across the temperature swings and damp-to-dry cycles typical of a Whatcom County year.

Airflow and Drainage Underneath

A deck built low to the ground or over poorly graded soil traps moisture underneath, which is exactly the environment moss, mold, and mildew need to take hold — both on the underside of the boards and on the ground below. Proper joist height, ventilation gaps, and grading or gravel underneath all reduce how much standing moisture the structure has to deal with through a wet winter.

Composite vs. Wood vs. PVC for This Climate

Each decking material has real trade-offs. We install composite most often in this area because it strikes the best balance of upkeep and durability for salt-air, high-rainfall conditions, but it's worth understanding why.

Material	Maintenance	Moisture Behavior	Typical Lifespan Here
Pressure-Treated Wood	Annual staining/sealing recommended	Absorbs water, prone to cupping and splintering if neglected	10-15 years with upkeep
Capped Composite	Occasional washing, no staining	Sheds water, resists rot, low absorption	25+ years
Cellular PVC	Occasional washing	Essentially waterproof, no wood content to rot	25-30+ years

PVC is a reasonable option for homeowners who want zero organic content in the board at all, but it comes at a higher material cost and a different look and feel underfoot — it can also get noticeably hot in direct sun. Capped composite gives most Custer homeowners the moisture performance they need without that premium, which is why it's our default recommendation unless a homeowner has a specific reason to go PVC.

Choosing the Right Composite Board

Capped vs. Uncapped

We only install capped composite — boards with a polymer shell fully wrapping the wood-plastic core. Uncapped composite exposes that core at the surface, and in a climate this wet, an exposed core absorbs moisture, stains more easily, and is far more hospitable to mold and mildew growth. The cap is what makes composite genuinely low-maintenance here; without it, you're back to washing and treating a surface almost as often as wood.

Color and Heat Considerations

Lighter and mid-tone board colors show less contrast when pollen, moss spores, or organic debris settle on the surface between cleanings, and they run cooler underfoot on the rare sunny day. Darker boards look sharp but need more frequent rinsing to stay looking that way in a climate where airborne debris and moisture are near-constant. This is a preference call, not a right-or-wrong one — we walk through the trade-off with each homeowner rather than pushing a single color line.

Moss and Mildew: What Actually Works

Moss doesn't grow on a clean, dry, well-drained composite surface nearly as readily as it does on wood or on a deck with poor airflow underneath. That said, no decking material is immune in a Whatcom County winter. What actually keeps a composite deck clean here is simple and doesn't require chemicals or specialty products in most cases:

Sweep debris off regularly, especially fallen leaves and needles that trap moisture against the board surface
Rinse with plain water on a regular basis — a pressure washer on a wide, low-pressure setting works, but a garden hose is often enough
Keep gutters and downspouts clear so runoff isn't dumping directly onto the deck surface
Trim back overhanging branches that keep sections of the deck shaded and damp longer than the rest
Address any standing water or pooling promptly — it usually points to a drainage or slope issue worth fixing at the source

If a deck is built with the right slope, board spacing, and ventilation underneath to begin with, this level of upkeep is genuinely all most homeowners need.

Our Process, Start to Finish

We approach every composite deck project in Custer the same methodical way:

On-site assessment of the existing structure (for replacements) or the site conditions and drainage (for new builds)
Structural evaluation of ledger attachment, footings, and joist spacing against current code requirements
Review of board options, colors, and fastener systems based on the site's sun exposure and moisture exposure
Proper flashing, joist protection, and substructure work before a single composite board goes down
Installation with corrosion-resistant, composite-rated fasteners and correct expansion spacing
Final walkthrough covering care, cleaning, and what to watch for through the first wet season

Homeowners considering composite decking as a replacement for an aging wood deck should expect installed costs to generally run higher per square foot than pressure-treated lumber, reflecting both material cost and the lower long-term maintenance burden — the exact number depends heavily on substructure condition, deck size, railing, and stairs, which is why we price each job after seeing the site rather than off a flat rate.

Common Problems We Get Called to Fix

A lot of our composite deck work in this area isn't new construction — it's repairing or replacing decks that were installed without accounting for local conditions. The recurring issues we see:

Boards fastened with standard exterior screws instead of composite-rated, corrosion-resistant hardware, leading to rust streaking and loosening
Ledger boards without proper flashing, causing hidden rot in the house framing behind the deck
Decks built too close to grade with little to no airflow underneath, trapping moisture and encouraging moss and mildew on the underside
Uncapped composite boards installed in fully shaded, damp yard sections where they never fully dry out
Poor drainage slope leaving standing water pooled on the deck surface after every rain

Most of these are avoidable with correct installation from the start, which is a large part of why we spend as much time on what's underneath the decking as we do on the decking itself.

Why Hire a Crew That Already Works Custer

Custer's mix of coastal exposure, tree cover, and rainfall pattern isn't identical to conditions twenty or thirty miles inland, and a deck built to a generic spec sheet doesn't always hold up the same way here. A crew that regularly works this part of Whatcom County has already seen which fastener types corrode too fast in the salt air, which board profiles actually shed water well under a long moss season, and where drainage tends to go wrong on local lots. That local pattern recognition is what keeps a deck build from becoming a repair call five years later.

If you're planning a new composite deck or replacing an aging wood one, we're happy to take a look and give you a straightforward, no-pressure estimate — including an honest read on what your site's drainage, sun exposure, and structure actually need before any boards go down. Use the form below to get started.