How is composite decking different from PVC decking?

Composite blends wood fiber with plastic, giving it a look and slight flex closer to natural wood, while PVC is fully synthetic with no wood content and typically resists moisture even more completely. PVC often costs more and can look slightly more "plastic," which is a trade-off some homeowners prefer to avoid. We can walk through both options based on your budget and how much you want the deck to read as natural wood.

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

Ask whether they'll show you the actual joist spacing and flashing plan for your specific board profile, not just the visible board pattern, since that's what determines long-term performance. Also ask how they handle drainage on sloped lots, what fastener hardware they use, and whether they're pulling the required local building permit. A contractor who can't answer those specifics clearly is worth a second look before you sign.

Do all composite decking brands perform the same in a wet, shaded climate?

No — performance varies significantly based on whether the board is fully capped, how dense the core is, and what surface treatments the manufacturer uses against algae and mold. Entry-level and uncapped products tend to show staining and fading noticeably sooner in shaded, damp conditions than mid-tier or premium capped composites. We'll point out which tier fits your specific site rather than just the lowest-cost option.

Does composite decking need a permit in Whatcom County?

Most deck construction or replacement, including composite decking on a new or altered structure, requires a building permit in Whatcom County, particularly if the deck is elevated or attached to the house. Requirements can vary based on deck size, height, and whether you're replacing an existing structure versus building new. We handle the permitting conversation as part of the estimate so there are no surprises mid-project.

Why does moss come back on my deck every year even after I clean it?

In shaded, damp areas like much of Edgemoor, moss spores are constantly present in the air and will resettle on any surface that stays damp and shaded long enough, so a one-time cleaning doesn't stop future growth. Board spacing, surface texture, and how much airflow reaches the deck all affect how fast it returns. A properly ventilated substructure and a twice-yearly cleaning routine keep it from getting ahead of you rather than eliminating it outright.

Edgemoor Composite Decking Built for Sudden Valley's Wet Climate

Edgemoor Decks Face a Different Set of Problems Than Decks Inland

If your property sits in or near Edgemoor, close enough to Bellingham Bay and the Sudden Valley shoreline to catch the marine air, your deck lives a harder life than a deck twenty miles inland. Salt-laden moisture rides in on the wind and settles into every joint, fastener, and shaded corner. Whatcom County's driving rain doesn't just fall straight down here — it comes in sideways off the water and gets driven under rail caps, behind fascia boards, and into end grain that wasn't sealed. And because so many Edgemoor lots sit under mature conifers with limited afternoon sun, decks here run a long moss and algae season that stretches from fall through late spring.

None of that means composite decking is a bad choice for this neighborhood. It means the installation has to account for those conditions from the start — not as an afterthought once the boards start looking green or the fasteners start weeping rust. This page covers what that actually looks like.

Why Composite Makes Sense Here — With Honest Caveats

Composite decking (a blend of wood fiber and plastic, usually with a protective cap layer) resists moisture absorption far better than raw lumber, which matters when a board is going to be damp more often than dry for half the year. It won't splinter, doesn't need annual staining, and holds up to the freeze-thaw cycles Whatcom County gets in winter without the surface checking that cedar and untreated pine eventually show.

It isn't maintenance-free, and we don't sell it that way. Composite still needs periodic cleaning to stay ahead of moss and mildew, the color can fade slightly over years of UV and salt exposure, and the substructure underneath it — the part nobody sees — still has to be built to shed water, because composite boards don't dry out the way wood does once trapped moisture gets underneath them.

Capped Composite vs. Uncapped

Most composite sold today is "capped" — a solid polymer shell wrapped around the wood-plastic core on some or all sides. In a climate like Edgemoor's, that cap layer is what actually keeps moisture and algae from working into the board itself. Uncapped or partially capped boards (usually the lower-cost end of a manufacturer's line) absorb more moisture at cut ends and exposed faces, and in a shaded, damp lot that shows up as premature graying and mildew staining years before a fully capped board would. We'll tell you plainly which tier a product falls into before you buy it.

What a Correct Composite Deck Build Involves

The decking boards get most of the attention, but in this climate the substructure and detailing decide whether the deck looks good in year eight or needs boards replaced by year four. A correct install includes:

Joist tape or a flashing membrane over every joist top, so fastener penetrations don't become water entry points into the framing
Proper joist spacing for the specific composite product — many composites require tighter spacing than dimensional lumber decking, especially on angled or picture-frame layouts
Ledger board flashing that actually sheds water away from the house rim joist, critical anywhere driving rain is a factor
Hidden fastener systems where the board profile allows it, which reduces the exposed metal that corrodes fastest in salt air
Gapping between boards set for the manufacturer's spec and adjusted slightly for our wet-season swelling, not just eyeballed
Ventilation underneath the deck so airflow can carry moisture out from below instead of letting it sit and feed mold growth on the joists
Stainless or coated fasteners rated for coastal/marine exposure, not standard exterior-grade hardware that will streak and weaken faster here

Skip any one of these and the boards themselves — even a premium capped composite — won't perform the way the warranty assumes they will.

Edgemoor's Specific Conditions We Build Around

Proximity to the Water

Salt air accelerates corrosion on anything metal and speeds up UV breakdown on unprotected surfaces. It's a bigger factor for fastener choice and railing hardware than it is for the decking boards themselves, since quality composite is largely inert to salt.

Tree Cover and Shade

Many lots in this part of Whatcom County keep significant tree canopy for privacy and windbreak. That's good for the house, but it means less direct sun reaching the deck surface — which is exactly what moss, algae, and lichen need to establish. Board placement, gap width, and even which composite color and texture you choose can make a real difference in how fast growth shows up on a shaded deck versus an open one.

Drainage Off the Lot

Sloped Sudden Valley terrain means deck framing sometimes sits closer to grade on the downhill side than plans intended. We check actual site drainage during the estimate, not just the framing plan, because a deck built to spec on paper can still trap water if the ground around the footings doesn't drain the way it's supposed to.

Our Process for an Edgemoor Composite Deck

Site visit and assessment — we look at sun exposure, tree cover, existing structure condition (if replacing an old deck), and how water currently moves across the lot.
Product selection — we walk you through capped vs. better-capped tiers, board profiles, and color/texture options that actually resist algae staining in shaded spots, rather than just what looks best in a showroom.
Framing and flashing — this is where most of the long-term performance gets decided, and it's the part we don't rush or skip line items on to hit a lower bid.
Installation — boards, hidden fasteners where applicable, railing, stairs, and any picture-framing or accent detailing you've chosen.
Final walkthrough — we go over the specific maintenance this deck will need given its exposure, not a generic care sheet.

Composite Tiers: What Actually Changes Between Them

Factor	Entry-Level Composite	Mid-Tier Capped	Premium Capped
Moisture resistance	Moderate — uncapped or single-side cap	Good — fully capped	Best — fully capped, denser core
Algae/mold resistance in shade	Lower, shows staining sooner	Solid	Best, often with added surface treatment
Fade resistance over years	Noticeable fading	Moderate fade	Minimal fade
Typical warranty length	Shorter, prorated	Longer, often 25 years	Longest, sometimes limited lifetime
Rough installed cost per sq ft	Lower end of range	Mid range	Higher end of range

As a broad range, homeowners in this area are typically looking at roughly $40 to $70+ per square foot installed depending on tier, board profile, railing choice, and how much framing work the existing structure needs. We'll give you a firm number for your specific deck after the site visit — we don't quote sight-unseen for structures where drainage and framing condition matter this much.

Maintenance That Actually Fits This Climate

Composite is lower-maintenance than wood, not maintenance-free, and Edgemoor's moss season means a slightly more active care schedule than a composite deck would need in a drier part of the state.

Rinse and soft-wash the surface at least twice a year — before and after the wettest months — to keep moss and algae from establishing
Keep gutters and downspouts near the deck clear so runoff isn't dumping directly onto boards or railing posts
Sweep fallen needles and leaf debris off regularly in fall; trapped organic matter holds moisture against the board surface and feeds staining
Check fastener and hardware condition annually, especially anything closer to the water side of the property
Avoid pressure washing at close range or high PSI directly into the cap layer — it can etch or dull the surface finish over time

Why a Crew That Already Works Sudden Valley and Edgemoor Matters

A lot of the decisions above — joist spacing for a given composite profile, how much ventilation a shaded deck actually needs, which fastener coating holds up this close to the water — aren't things you learn from a spec sheet. They're things a crew learns from building and later servicing decks in this specific stretch of Whatcom County, season after season. We've built and repaired decks throughout Sudden Valley and the surrounding Edgemoor area, and we bring that site-specific judgment to every estimate, not just a generic install checklist.

If you're weighing composite decking for a home in Edgemoor, we're glad to come out, look at your lot's specific sun and drainage situation, and give you a straight answer on what it'll take to build it right — no pressure, no inflated scope. Reach out for a free estimate using the form below.