How is composite decking different from capped polymer or PVC decking?

Composite decking blends wood fiber with plastic, usually with a protective cap layer on modern boards, while PVC/polymer decking is fully synthetic with no wood content. Composite tends to feel and look closer to natural wood, while PVC is generally more resistant to moisture absorption but can cost more. We help homeowners weigh both based on their budget, sun exposure, and how much natural wood look they want.

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

Ask whether they follow the manufacturer's specific fastening and spacing requirements, since improper installation can void a composite board's warranty even if the material itself is fine. Also ask how they handle framing and flashing at the house connection, and whether they use corrosion-resistant hardware — that's often the real difference between a deck that lasts and one that doesn't in this climate. A contractor who can answer specifically, not just say "we've done a lot of decks," is a good sign.

Do all composite decking brands perform the same in wet, salty climates?

No — boards vary in cap technology, core density, and how they handle moisture at cut edges, and cheaper or older-generation composite can be more prone to moisture wicking and staining. We work with a handful of brands whose capped boards have held up well in coastal Pacific Northwest conditions and can walk through the differences using actual samples rather than marketing claims.

Can composite decking be installed directly over an existing wood deck frame?

Sometimes, but only if the existing framing is fully sound — composite is heavier than many people expect, and it doesn't forgive weak or rotted joists the way a quick cosmetic fix might suggest. We always inspect the substructure first, because installing new decking over compromised framing just hides the problem instead of solving it.

Why does moss come back on decks in this area even after cleaning?

Moss and algae spores are constantly present in the air in wet, shaded Pacific Northwest environments, so any surface that stays damp and shaded long enough will host new growth after a cleaning, not just the original spot. Improving drainage, sun exposure, and airflow under and around the deck slows regrowth significantly, even though it won't eliminate the need for occasional cleaning altogether.

Composite Decking in Alger: Built for PNW Rain, Salt Air & Moss

Composite Decking Built for Alger's Weather, Not Just Its Looks

Alger sits in the kind of Pacific Northwest microclimate where a deck earns its keep the hard way. Between the salt-laden air coming off the water, driving rain that finds its way into every seam and fastener hole, and a moss season that seems to stretch longer every year, an outdoor deck here is under more or less constant low-grade attack. Composite decking, when it's specified and installed correctly for this climate, holds up to that pressure far better than untreated wood ever will. But "composite" isn't a magic word — the material only performs as well as the framing, drainage, and fastening underneath it. This page is about what that actually looks like for a deck built in Alger, not a generic decking overview.

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

Before talking about materials, it helps to understand the three forces working against any deck in this part of Whatcom County. They don't act alone — they compound each other.

Moisture That Doesn't Just Sit on Top

Driving rain doesn't fall straight down here — wind pushes it sideways, under rail caps, into board gaps, and along ledger connections where the deck meets the house. On a poorly built deck, that water gets trapped between boards and joists, or behind flashing that was never properly lapped. The surface can look fine for years while the framing underneath quietly rots. This is the single biggest reason decks fail early in this region, and it has almost nothing to do with whether the decking boards themselves are wood or composite.

Salt Air and Hardware Corrosion

Airborne salt accelerates corrosion on anything metal — fasteners, brackets, joist hangers, railing hardware. A screw or bracket that would last decades inland can start rusting and weakening in a fraction of that time in a salt-air environment. Once a fastener corrodes, it loses grip strength long before it looks bad enough to notice from the surface, which is why hardware selection matters as much as the decking material itself.

Moss, Algae, and a Slippery Surface

Shade, moisture, and mild temperatures are exactly what moss and algae need to establish, and a long wet season here gives them plenty of time to do it. Beyond looking neglected, a mossy or algae-coated deck surface gets genuinely slick underfoot — a real safety issue on stairs and near entry points. Board texture, drainage, and how much sun and airflow a deck gets all affect how fast that buildup returns after cleaning.

Composite vs. Wood vs. PVC: An Honest Comparison for This Climate

There's no single "best" decking material for every situation — but for the conditions Alger deals with, the trade-offs are pretty clear-cut once you lay them out.

Material	Moisture Behavior	Moss/Algae Resistance	Maintenance	Typical Lifespan Here
Pressure-treated wood	Absorbs and releases moisture; prone to cupping, splitting, and rot at fastener points	Low — porous surface holds spores	Annual sealing/staining recommended	10–15 years before major repair
Composite (capped)	Resists absorption; core doesn't rot	Moderate to good, depending on cap and texture	Periodic washing, no sealing/staining	25+ years with proper install
PVC/vinyl decking	Fully moisture-resistant	Good, but very smooth profiles can show algae film	Low; occasional washing	25+ years

We install composite most often in Alger because it strikes a practical balance: it handles the wet season without the yearly upkeep wood demands, it's less prone to the brittleness some early PVC products showed in colder snaps, and today's capped composite boards resist moss and staining far better than the uncapped composite of a decade or two ago. We don't push one brand over another — we spec the board based on the deck's exposure, budget, and how much sun it actually gets, and we're upfront when a lower-maintenance option costs more up front.

What a Correct Composite Deck Build Actually Involves

The decking boards get all the attention, but most deck failures in this climate start below the surface. A correct build addresses each of these layers.

Framing You Won't See Again

Joists and beams need to be rated for exterior use and, ideally, wrapped or capped where composite decking will sit directly on top of them — this keeps moisture that gets past the boards from soaking into bare lumber. Ledger board attachment to the house gets flashed properly, since that's the single most common point where water intrudes into a structure over time.

Drainage and Airflow Underneath

A deck built low to the ground or against a slope without a clear path for water to escape stays damp longer after every rain, which is exactly what moss and rot need. We grade and gap for drainage and make sure there's airflow underneath — even a low deck — so the structure actually gets a chance to dry between storms instead of staying saturated through the whole wet season.

Fasteners and Hardware That Match the Environment

Given the salt-air corrosion issue, we use fasteners and structural hardware rated for coastal/marine-grade exposure rather than standard-grade hardware. It costs a bit more up front and it's the difference between hardware that's still sound in fifteen years and hardware that's already rusting through in five.

Choosing the Right Board

Within composite, board texture and color matter more here than in drier climates. Lighter colors and certain grain textures show water spotting and pollen/algae film differently than darker, more heavily textured boards. We walk homeowners through actual samples rather than a catalog page, because how a board looks in a showroom and how it looks on a shaded, rain-exposed deck in Alger are two different things.

Our Process for a Composite Deck Project

Every deck is a little different, but the sequence stays consistent:

On-site assessment — we look at sun exposure, drainage, existing structure (if it's a replacement), and how the deck ties into the house.
Design and material selection — board brand, color, and railing system are chosen together, with honest trade-offs explained, not just upsold.
Structural prep — framing repair or replacement, joist protection, and proper ledger flashing happen before a single composite board goes down.
Installation — hidden fastening systems where appropriate, correct board spacing for expansion and drainage, and manufacturer-spec hardware throughout.
Final walkthrough — we cover basic care specific to the board you chose so there are no surprises the first time moss season rolls around.

Living With a Composite Deck Through Whatcom County's Wet Season

Composite cuts maintenance drastically compared to wood, but "low-maintenance" isn't "no-maintenance" — especially with the moss and algae pressure this area sees. A simple seasonal routine keeps a composite deck looking and performing the way it should:

Sweep debris (leaves, needles, pollen) off regularly — trapped organic material is what feeds moss and algae growth
Wash the surface with a soft-bristle brush and mild soap/water a couple of times a year, more often in heavily shaded areas
Avoid pressure washers on the highest settings directly against board seams — it can drive water into fastener points
Check railing posts and stair connections annually for any looseness, which can signal a hardware issue underneath
Keep gutters and downspouts near the deck clear so runoff isn't dumping directly onto or under the structure
Trim back overhanging branches where practical to cut down on shade and debris that accelerate moss growth

What Affects the Cost of a Composite Deck in Alger

Pricing varies by project, but the main cost drivers are consistent:

Size and shape — square footage, plus how many angles, stairs, or transitions the design includes
Substructure condition — a full rebuild of failed framing costs more than decking installed over sound, code-compliant structure
Board tier — composite pricing spans a wide range depending on brand, cap technology, and warranty length
Railing and hardware — composite or metal railing systems cost more than basic wood but tend to match the deck's lifespan better
Site access — slope, height off the ground, and how materials get to the build site all factor into labor

We give a straight, itemized estimate rather than a vague ballpark, and we'll always explain what's driving the number — there's no reason a homeowner should have to guess why one quote is higher than another.

Why a Crew That Already Works in Alger Makes a Difference

A deck built by someone unfamiliar with this specific stretch of climate tends to get the visible parts right and the invisible parts wrong — the flashing detail, the hardware grade, the drainage gap that seems unnecessary until the second wet winter. Crews who work Alger and the surrounding Sudden Valley area regularly see how decks actually age here, not just how they perform in a showroom or a manufacturer's spec sheet written for a different climate. That local track record is what informs the framing choices, fastener grade, and board recommendations on this page — it's not theoretical.

If you're planning a new composite deck or replacing one that's showing rot, rust, or moss buildup, we're happy to take a look and put together a straightforward, no-pressure estimate. Use the form below to get started.