How is composite decking different from the pressure-treated wood most older decks around here use?

Composite boards are a wood-plastic blend that absorbs far less moisture than solid wood, so they resist cupping, splintering, and staining through our long wet season. They also skip the annual sanding and sealing that pressure-treated wood needs to stay in good shape. The trade-off is a higher upfront material cost in exchange for less ongoing maintenance.

What should I check when vetting a contractor for a composite deck build, beyond just price?

Ask specifically about their fastener and hardware spec, how they flash the ledger board where it meets the house, and how they handle ventilation under the deck — these details matter more to long-term performance than the brand of board they install. Also ask whether their warranty is the manufacturer's, their own workmanship warranty, or both. A contractor who can answer those clearly without hedging is usually one who's done this build correctly before.

Are all composite decking brands built the same way?

No — boards vary by how they're capped (fully wrapped vs. capped on fewer sides), the wood-to-plastic ratio, and the fastener system they're designed around. Some tiers hold color and resist staining noticeably better than others, especially in a climate with this much sun-to-rain cycling. We'll go over which options fit your budget and exposure during an estimate rather than defaulting to one product for every job.

Do composite deck boards need special fasteners, and does it matter for this area?

Most composite decking uses a hidden clip fastener system rather than face screws, and in a salt-air, high-rain climate the hardware needs to be corrosion-rated, not standard interior-grade steel. Using the wrong hardware is one of the most common causes of early rust staining and loose connections we see on decks in this area. It's a small cost difference upfront that avoids a much bigger repair later.

Does Goshen's location near the Sound and the Canadian border affect how a deck should be built?

The combination of frequent rain, a long moss season, and periodic salt-tinged air off the Sound means drainage, ventilation, and hardware choices matter more here than in a drier inland climate. It doesn't change what composite decking is, but it does change how the substructure and fasteners need to be specified to hold up over decades rather than years. That's the main reason we build to a higher hardware and drainage standard than a generic spec sheet calls for.

Composite Decking in Goshen: A Sumas, WA Buyer's Guide

Why Goshen Decks Take a Beating

Goshen sits in the part of Whatcom County where weather doesn't do things halfway. Winters bring long stretches of driving rain that don't let up for days. Spring and fall add heavy dew and fog that keep exterior surfaces damp well into the afternoon. Add in the moss season that runs from roughly October through April, plus the salt-tinged air that moves inland off the Sound on a west wind, and you've got a combination that ages an outdoor deck faster than most homeowners expect. None of that is a reason to avoid a deck — it's just the reason a Goshen deck has to be built differently than one going in somewhere dry and inland.

A composite deck that's installed correctly for this climate should outlast a poorly built one by decades, not years. The material itself matters, but so does the substructure underneath it, the fasteners holding it together, and whether the crew actually accounts for how water and moss behave in this part of Whatcom County. That's the whole point of this page — not to sell composite decking in general, but to explain what a composite deck needs to hold up specifically in Goshen.

What Composite Decking Actually Solves Here

Composite boards are made from a blend of wood fiber and plastic, capped or coated to resist moisture absorption. In a climate like ours, that matters for a few concrete reasons:

They don't absorb standing water the way solid wood does, so they're less prone to swelling, cupping, and splintering after a wet winter.
They don't need annual staining or sealing, which matters when the dry window to do that work safely each year is short.
Modern capped boards resist mold and algae staining better than uncapped wood or older composite generations — though "resist" doesn't mean immune, and we'll get to that.
They hold color and texture longer under UV and rain cycling, so a deck doesn't gray out or go blotchy after a couple of seasons.

What composite decking does not solve on its own is moss and mildew growth on the surface, or moisture problems in the framing underneath. Those come down to how the deck is built, not just what the boards are made of.

What a Correct Build Looks Like in This Climate

Substructure and Drainage

Most deck failures we get called out to inspect aren't a board problem — they're a framing problem. Joists that sit in standing water, ledger boards without proper flashing, or a substructure with no airflow underneath will rot or corrode long before the composite decking on top shows any wear. In a climate that stays wet for months at a stretch, we treat drainage and airflow as non-negotiable:

Joist tape or a comparable moisture barrier on every joist top, so fastener penetrations don't become entry points for water.
Proper slope away from the house, even on a low deck, so water doesn't pool against the ledger.
Enough clearance and ventilation underneath the deck that the framing can actually dry out between rain events instead of staying damp all winter.
Corrosion-resistant hardware throughout — coated or stainless fasteners, hangers rated for exterior/coastal exposure, not standard interior-grade hardware.

Fasteners and Hidden Hardware

Composite boards are usually installed with hidden fastener clip systems rather than face screws, which gives a cleaner look and avoids the small water traps that screw heads create. In a salt-air, high-rain area, the fasteners and clips need to be rated for that exposure — plain steel components will corrode and stain the boards around them well before the decking itself is due for replacement. We spec hardware for the climate it's going into, not just whatever ships cheapest with a given board line.

Board Selection and Ventilation

Board spacing matters more here than in a dry climate. Composite boards expand and contract with moisture and temperature, and if gapping is too tight, water sits between boards instead of draining through. We set gapping to manufacturer spec and adjust slightly based on install temperature and expected moisture exposure — a deck installed on a cold, damp day needs different gapping than one installed in August.

Composite vs. Wood vs. PVC: An Honest Comparison

There's no universally "best" decking material — each has trade-offs that matter differently depending on budget, maintenance appetite, and how exposed the deck is to weather.

Material	Moisture Behavior in Our Climate	Maintenance	Typical Lifespan
Pressure-treated wood	Absorbs water readily; prone to cupping, splintering, and moss growth without regular sealing	Annual cleaning and re-sealing recommended	10–15 years before major repair or replacement
Composite (wood-plastic blend)	Low absorption; capped boards resist staining but surface moss/mildew still needs occasional cleaning	Periodic washing, no staining or sealing	20–30+ years depending on brand and install quality
PVC (cellular)	Essentially non-absorbent; performs well in constant moisture	Low; occasional washing	25–30+ years, typically at a higher material cost

For most Goshen homeowners, composite lands in the sweet spot: meaningfully better moisture performance than wood without the premium cost of full PVC systems. We'll walk through where your project actually falls on that spectrum during an estimate rather than defaulting to one answer for every house.

Our Process, Start to Finish

On-site assessment — we look at drainage, existing ledger/framing condition if it's a rebuild, sun and shade exposure, and how the deck will actually be used.
Design and material selection — board profile, color, fastener system, and railing to match the house and budget.
Substructure work — framing, flashing, and joist protection built to hold up through a full wet season before a single composite board goes down.
Decking installation — hidden-fastener composite boards installed to manufacturer spec, with gapping and ventilation set for this climate.
Final walkthrough — we go over basic care, warranty paperwork, and what to expect from the boards through the first wet season.

Moss, Mildew, and Salt Air: What Ongoing Care Actually Looks Like

Composite decking is low-maintenance, not no-maintenance. In Goshen's moss season, even the best-capped boards can develop a light surface film if the deck sits shaded and damp for months without any airflow or sun exposure. That's not a defect in the material — it's biology finding a surface to grow on, same as it will on a roof, a fence, or a sidewalk. A simple seasonal wash (soft brush, mild soap, garden hose or low-pressure washer) before moss gets a foothold keeps most decks looking clean year-round. Salt air mostly affects metal components rather than the boards themselves, which is why hardware selection during installation matters as much as the decking material.

A Simple Seasonal Checklist

Early fall: clear leaves and debris from board gaps and drainage points before the rain sets in.
Mid-winter: check that under-deck ventilation isn't blocked by stored items or overgrown landscaping.
Late winter/early spring: wash the surface before moss establishes, especially on shaded sides of the house.
Annually: inspect railing posts and stair connections for any movement, which is often the first sign of a framing issue, not a decking issue.

What Drives the Cost of a Composite Deck Here

Every project is different, but the same handful of factors move the price up or down on most Goshen jobs:

Factor	Why It Matters
Board tier and brand	Entry-level capped composite vs. premium multi-layer boards affects both material cost and expected lifespan
Substructure condition	A rebuild with rotted or under-spec framing costs more than decking over sound, well-built framing
Height and railing requirements	Elevated decks need code-compliant railing and stair systems, which adds material and labor
Site access and drainage grading	Sloped lots or tight access can add labor time for both structure and cleanup
Fastener and hardware spec	Corrosion-rated hardware costs more up front and pays off in fewer callbacks over the deck's life

We'll give you a real number after seeing the site — broad online estimates rarely account for what's actually under an existing deck or what a given lot needs for proper drainage.

Mistakes We Commonly Find on Existing Decks

When we're called out to look at a deck that's failing early, it's almost never the composite boards themselves. The recurring issues we see around this area are:

Ledger boards attached to the house without proper flashing, letting water track behind the siding.
Standard steel screws or clips used instead of corrosion-rated hardware, leading to rust staining and weakened connections within a few years.
No ventilation gap under low decks, trapping moisture against the framing year-round.
Board gapping installed too tight for our rainfall and temperature swings, causing water to sit between boards instead of draining.

Every one of these is preventable at the framing and fastener stage — they're expensive to fix after the fact and nearly free to get right the first time.

Why Hiring a Crew That Already Works Goshen Matters

A lot of decking problems in this area trace back to a build that would have been fine somewhere drier. A crew that hasn't worked Whatcom County's rain patterns, moss cycles, and drainage quirks before will often default to generic installation specs that don't account for what a Goshen winter actually does to a deck. We're a Sumas-based crew, so this isn't theoretical for us — it's the same weather we build in every job. That local familiarity shows up in small decisions: where we put ventilation gaps, which hardware we spec, how we grade drainage away from the house, and how we set expectations for seasonal upkeep before we ever hand you a quote.

Questions Worth Asking Any Contractor Before You Hire

What fastener and hardware system do you use, and is it rated for coastal/high-moisture exposure?
How do you handle ventilation and drainage under the deck, not just the boards on top?
Do you flash the ledger board where it meets the house, and can you explain how?
What's your warranty structure — is it the manufacturer's, yours, or both, and what does it actually cover?
Have you built decks in this specific area before, and can you speak to how they've held up?

If you're weighing composite decking for a home in Goshen, we're happy to walk the site, look at what's there now if you're replacing an old deck, and give you a straightforward estimate with no pressure to sign anything on the spot. The form below is the fastest way to get that started.