Ferndale Window Custer sits close enough to the water and open farmland that its decks take a beating most inland homes never see. Salt-laden air off the Strait, wind-driven rain that finds every gap in a poorly built ledger connection, and a moss season that can stretch from October through April all work against a deck that wasn't built with this specific climate in mind. Composite decking, installed correctly, holds up to that combination better than most alternatives — but "composite decking" covers a wide range of products and installation quality, and the difference between a deck that lasts and one that fails early almost always comes down to what's underneath the boards, not the boards themselves.
Why Custer's Climate Is Hard on Decks
Whatcom County weather doesn't hit a deck all at once — it wears it down slowly, in ways that aren't obvious until a few seasons in. Three factors matter most for anything built outdoors here:
- Salt air corrosion. Fasteners, brackets, and any exposed metal hardware near the coast corrode faster than the same materials would inland. Standard deck screws and joist hangers that aren't rated for coastal exposure can start rusting within a few years.
- Driving rain. Rain here rarely falls straight down. Wind pushes it sideways and up under boards, into ledger connections, and behind fascia. Any gap in the flashing or drainage plane becomes a moisture entry point.
- A long moss season. Shaded, north-facing, and low-airflow deck areas stay damp for months at a stretch. Moss and algae take hold on surfaces that don't drain or dry quickly, and they make boards slick underfoot long before they cause structural harm.
None of these factors are unique to Custer, but the combination — coastal salt exposure plus heavy regional rainfall plus long damp stretches — is more aggressive than what a deck in, say, eastern Washington ever has to handle.
Why Composite Decking Makes Sense for This Climate
Composite boards don't absorb water the way wood does, so they don't swell, cup, or split from repeated wet-dry cycles the way an untreated or under-maintained wood deck will. They also don't need annual staining or sealing to stay protected — a real advantage in a climate where that maintenance window (a few dry, warm days in a row) can be hard to find between October and June.
That said, composite isn't maintenance-free, and it isn't automatically the right call for every application. It performs best when the substructure underneath is built to actually drain and dry, because composite boards themselves don't rot — but the framing, fasteners, and ledger connection underneath them absolutely can if water gets trapped against them. A composite deck installed over a poorly ventilated or poorly flashed frame can still fail structurally even while the boards on top look fine. That's the part homeowners rarely see, and it's where most of the actual workmanship in a deck build happens.
What a Correct Composite Deck Installation Involves
Framing and Substructure
The joists, beams, and posts underneath a composite deck need to be pressure-treated lumber rated for ground contact where applicable, spaced correctly for the specific composite product's span rating (composite boards generally require tighter joist spacing than wood — usually 16 inches on center, sometimes less), and set up to shed water rather than trap it against the frame.
Ledger Attachment and Flashing
Where a deck attaches to the house, the ledger board connection is the single most common failure point on any deck, wood or composite. It needs proper flashing that directs water away from the house's wall assembly, not just caulk or a wrap that will fail in a few seasons of driving rain. This is also where corrosion-resistant, coastal-rated fasteners and hardware matter most, given the salt air in this area.
Fasteners and Hardware
Hidden fastener systems (clips that hold boards from underneath, invisible from the surface) are standard on most composite decks now, but the clips, screws, and joist hangers still need to be rated for the exposure they'll see. In a coastal-influenced area, that means stainless steel or coated hardware rated for that environment — not the cheapest fastener that happens to fit.
Drainage and Airflow Underneath
A deck built low to the ground, over a patio, or in a shaded yard needs deliberate airflow and drainage planning underneath — gapping, slope, and sometimes a under-deck drainage system — so moisture doesn't sit trapped against the framing all winter. This is where the moss and algae problems this area sees usually start: not on the boards themselves, but in low-airflow pockets underneath and around the perimeter.
Composite Decking Product Considerations
Not all composite decking is built the same way, and the differences matter more in a wet climate than in a dry one. Here's a general comparison of what's commonly available:
| Material | Moisture Behavior | Maintenance | Typical Trade-off |
|---|---|---|---|
| Wood (cedar, treated fir) | Absorbs water, prone to cupping/splitting | Annual staining/sealing | Lowest upfront cost, highest ongoing labor |
| Capped composite | Water-resistant shell over composite core | Periodic wash-down | Strong balance of durability and cost for this climate |
| Uncapped composite | More moisture-permeable, can fade/stain over time | More frequent cleaning | Lower cost than capped, shorter service life in wet climates |
| PVC/cellular decking | Fully water-resistant, no wood content | Lowest maintenance | Higher upfront cost, different look/feel underfoot |
For most homes in this area, capped composite hits the right balance — it resists the moisture cycling and moss growth that uncapped products struggle with, without the added cost jump to full PVC. We'll walk through the specific product lines that fit your budget and the deck's exposure during the estimate rather than pushing one brand across every job.
Our Process, From Estimate to Finished Deck
1. On-Site Assessment
We look at the deck's exposure — how much sun and airflow it gets, whether it's tied into the house or freestanding, and how water currently moves (or doesn't move) around the area. This tells us what the substructure actually needs, not just what the finished surface should look like.
2. Framing and Structural Work
Any existing structure that's compromised — soft framing, a poorly flashed ledger, undersized joists — gets addressed before a single composite board goes down. Building composite decking over a bad frame just hides the problem for a few years.
3. Installation
Boards go down per the manufacturer's span and fastening specifications for this climate, with attention to expansion gaps (composite still moves seasonally, just less than wood) and consistent drainage slope.
4. Finish Details
Fascia, stair details, and railing tie-ins are finished with the same coastal-rated hardware as the structural work, so there isn't a weak point hiding in the trim.
5. Walkthrough
We go over basic care for the specific product installed — most composite decks need very little, but a quick rundown of what to expect in year one helps avoid surprises.
Maintenance in a Long Moss Season
Composite decking is low-maintenance, not no-maintenance, especially in an area with as much sustained dampness as Whatcom County sees. A short seasonal routine goes a long way:
- Sweep debris (leaves, needles, seed pods) off the deck regularly — trapped organic matter is what feeds moss and algae growth in the first place
- Rinse the surface with plain water a few times a year, and use a soft-bristle brush with mild soap on shaded or low-traffic areas where moss tends to establish
- Check that gaps between boards stay clear so water can drain through rather than pool on the surface
- Keep an eye on the area underneath the deck — clear vegetation or debris that blocks airflow to the framing
- Inspect ledger flashing and visible hardware annually for any signs of corrosion or water staining on the house siding above the connection
Cost Factors to Expect
| Factor | Why It Matters |
|---|---|
| Deck size and shape | More linear footage of framing, board cuts, and fastening; complex shapes add labor |
| Height and access | Elevated decks need more substructure and railing work than ground-level ones |
| Existing structure condition | Reusing sound framing costs less than replacing a compromised substructure |
| Composite product tier | Uncapped, capped, and PVC decking span a wide price range per square foot |
| Site exposure | Coastal-rated hardware and added drainage detailing for shaded or low-airflow sites add cost but reduce long-term problems |
Broad ranges are all anyone can honestly quote before seeing the site — final numbers depend on the specifics above. We'll give you a real, itemized number after a walkthrough rather than a ballpark that doesn't hold up once work starts.
Why Hire a Crew That Already Works Custer
A lot of deck problems in this region trace back to plans and products that were fine somewhere else but weren't adjusted for what Custer actually deals with — salt-influenced air, sideways rain, and shaded areas that stay wet for months. A crew that already works this area knows to spec coastal-rated hardware without being asked, knows which composite products actually hold up here versus which ones look good in a showroom, and knows how to detail a ledger and drainage plane for the rain patterns this part of Whatcom County sees. That local familiarity shows up less in the finished look of the deck and more in how it performs five and ten years out.
If you're weighing composite decking for a home in Custer, we're happy to walk the site, look at your existing structure if there is one, and give you a straightforward, no-pressure estimate — just fill out the form below.