Lynden Siding Composite Decking Built for Kendall's Climate
Kendall sits at the edge of Whatcom County where the valley starts climbing toward the foothills, and that location comes with a specific kind of weather punishment: long wet winters, heavy dew, low winter sun angles that leave shaded areas damp for days at a time, and a moss season that can run from October clear through April. A deck out here doesn't just get rained on — it stays damp. That's the difference between a deck that looks good for five years and one that looks good for twenty-five.
Composite decking was built to solve exactly this problem. It doesn't absorb water the way wood does, it doesn't need annual staining, and it resists the slow rot that eventually gets into every wood deck's joints, fastener holes, and end grain. But composite isn't magic — installed wrong, or installed with the wrong hardware and drainage details for our climate, it can still trap moisture, grow moss on the surface, or fail at the fasteners. The install matters as much as the material.
What Kendall Homes Actually Deal With
Every deck we look at in this area has the same underlying stressors, just in different combinations depending on the lot:
- Moss and algae growth — shaded decks under trees or on the north side of a house stay damp long enough for moss spores to take hold, especially on textured wood-grain surfaces that hold moisture in the grain pattern.
- Standing water at low points — decks that weren't framed with a slight pitch collect puddles that never fully evaporate during our wet months, which accelerates staining and mildew.
- Ledger board and rim joist rot — the connection point where a deck attaches to the house is the single most common failure point we find, because flashing was skipped or done wrong on the original build.
- Fastener corrosion — cheap or mismatched screws streak composite boards with rust stains and eventually work loose as they corrode.
- UV fade combined with damp — Whatcom County gets enough sun in summer to fade lower-grade composite unevenly, especially where part of the deck is shaded and part isn't.
None of these are exotic problems. They're just what happens to an exterior structure in a place with driving rain, salt-tinged marine air moving up from the Sound, and long stretches without direct sun.
Why Composite Makes Sense Here Specifically
Solid wood decking needs regular sealing to keep water out of the grain, and once that maintenance schedule slips — which it almost always does — the wood starts absorbing moisture, swelling, cupping, and eventually rotting from the inside out. In a climate with as much sustained dampness as we get around Kendall, that maintenance window is short. Composite doesn't need that upkeep. It's engineered to shed water rather than absorb it, which is the single biggest advantage in a region where "dry season" is a relative term.
What a Correct Composite Deck Installation Involves
A composite deck is only as good as what's underneath it. We don't treat the substructure as an afterthought — it's where most long-term failures start.
Framing and Structure
We check joist spacing against the manufacturer's specs for the specific composite board being used — some boards require tighter joist spacing than standard wood decking, especially on diagonal layouts. We also confirm the frame is pressure-treated rated for ground contact where it's close to grade, since our soil stays damp for months at a stretch.
Ledger Attachment and Flashing
Where the deck ties into the house, proper flashing is non-negotiable. This is the point where water runs down the siding, hits the ledger board, and either sheds away or works its way behind the band joist into the house framing. We flash this connection correctly every time — it's the cheapest insurance against the most expensive repair.
Drainage and Pitch
We build in a slight pitch away from the house so water moves off the deck instead of pooling. On lower decks close to grade, we also think about airflow underneath — a deck that can't breathe underneath stays damp longer after every rain, which feeds moss growth on the underside of boards and joists.
Hidden Fasteners and Board Spacing
Most composite systems today use hidden fastener clips rather than face screws, which avoids the rust-streak problem entirely and gives a cleaner look. Board spacing has to account for composite's expansion and contraction with temperature swings — too tight and boards can buckle, too wide and debris collects in the gaps.
Railing and Stair Integration
Railings and stair stringers need to be sound structurally, not just decorative. We check post attachment points carefully since these take the most repeated stress and are usually the first thing a home inspector or buyer notices.
Comparing Composite to the Alternatives
| Factor | Composite Decking | Pressure-Treated Wood | Cedar |
|---|---|---|---|
| Moisture resistance in wet climate | High — doesn't absorb water like wood | Moderate — needs sealing to hold up | Moderate — naturally rot-resistant but still absorbs moisture |
| Moss/algae resistance | Better on smooth or capped boards; still needs occasional cleaning | Prone to moss in shaded, damp areas | Prone to moss, though less than PT pine |
| Maintenance | Occasional wash, no staining or sealing | Annual or biannual sealing/staining required | Regular sealing to maintain color and protection |
| Upfront cost | Higher material cost | Lowest material cost | Mid-to-high material cost |
| Long-term cost | Lower — minimal upkeep over 20+ years | Higher — ongoing sealing, earlier replacement | Higher — ongoing sealing, earlier replacement |
| Fastener/warranty structure | Manufacturer warranties on boards, often 25+ years | No material warranty, only workmanship | No material warranty, only workmanship |
Pressure-treated and cedar both have their place, and we install both when a homeowner wants that look or has budget constraints. But for a deck that's going to sit in Whatcom County weather for the next few decades with minimal upkeep, composite is generally the more honest long-term recommendation.
Our Process for a Kendall Composite Deck Project
- On-site assessment — we look at the existing structure (if replacing a deck) or the site conditions (if building new), checking grade, drainage, sun/shade exposure, and how the deck ties into the house.
- Material walkthrough — we go over composite board options, colors, and price tiers honestly, including where a mid-tier board makes more sense than the top-tier one for a given budget.
- Structural plan — joist layout, flashing details, footing placement (for new builds), and drainage pitch get worked out before any material is ordered.
- Installation — framing first, then flashing and waterproofing at the ledger, then decking, railings, and stairs.
- Final walkthrough — we check fastener seating, board spacing, railing rigidity, and drainage before calling the job done.
What to Check Before You Hire Anyone for This
- Do they flash the ledger board properly, or just bolt it to the house?
- Do they know the specific joist spacing requirements for the composite brand you're considering?
- Will they show you the drainage plan before building, not after you notice puddles?
- Are they using hidden fastener systems, or face-screwing boards and leaving rust streaks down the road?
- Do they carry liability insurance and pull the required permit for a deck of this size?
Why Local Experience in This Area Matters
A contractor who mostly works drier climates or different soil conditions can build a technically fine deck that still struggles here, because they're not used to designing for standing moisture, moss pressure, and the marine-influenced rain patterns that move through Whatcom County. Working in and around Kendall and Lynden regularly means we've already seen how different composite lines actually perform locally — not just what the manufacturer's brochure says, but how a board looks after five wet winters on a shaded lot versus a sunny one.
That local pattern recognition changes real decisions: which board colors show water spotting less, where extra drainage detail is worth the cost, and which framing shortcuts that might pass in a drier region will cause problems here in year three or four.
Maintenance Once It's Built
Composite decking is low-maintenance, not no-maintenance. A seasonal rinse to clear pollen, moss spores, and organic debris — especially before the wet season sets in — keeps the surface from ever giving moss a foothold. Keeping gutters and downspouts clear near the deck also matters more here than in drier climates, since overflow during heavy rain events is a common source of unexpected moisture at deck edges.
If you're planning a new deck or replacing an aging one in Kendall, we're happy to walk the site, look at what you're working with, and give you a straight assessment of what it needs. Reach out below for a free, no-pressure estimate.