Lynden Siding Siding Built for Sumas, Washington Homes
Sumas sits out at the edge of Whatcom County, and homes here take a steady beating from the same weather that shapes exterior work all across this part of Washington. Damp air moves in off the water and settles into the valley, driving rain works its way into anything with a seam or a soft spot, and a long, gray moss season gives algae and mildew months at a time to get established on north-facing walls and shaded siding. If you've owned a home out here for more than a few years, you've probably already seen what that combination does to paint, trim, and older siding materials.
Lynden Siding Company sends the same local crew out to Sumas that works throughout Whatcom County. We're not a call center dispatching whoever's closest — the people who show up to measure your house are the same people who install it, and they've seen how this specific climate treats different siding products over time. That matters more than it sounds like it should. A crew that only works in dry inland climates makes different assumptions about flashing, ventilation, and caulk joints than a crew that's been doing this work in the Pacific Northwest for years.
What This Climate Does to Siding
A few things show up again and again on homes in this area:
- Moisture intrusion at seams and penetrations. Driving rain doesn't fall straight down out here — wind pushes it sideways into joints, corners, and anywhere trim meets siding. Any gap in the water-management layer becomes a slow leak.
- Moss and algae growth. Shaded walls, roof lines, and anything under tree cover stay damp for extended stretches during the fall and winter. Materials that hold moisture at the surface give moss a foothold that's hard to fully remove without damaging the finish underneath.
- Paint and finish breakdown. Repeated wet-dry cycling stresses paint film over time. On materials that rely on field-applied paint, that means recurring maintenance to keep water out once the coating starts to fail.
- Swelling and softening at cut edges and butt joints. Wood-based and composite products that aren't fully sealed at every cut edge are especially vulnerable where installers didn't seal every exposed edge — moisture gets in and doesn't leave.
Why We Install James Hardie — Not Alternatives
We install James Hardie fiber cement exclusively. We don't install vinyl, LP SmartSide, Cemplank, Allura, or unfinished wood siding, and that's a deliberate standard, not an oversight. Each of those products has legitimate uses and reasonable trade-offs — but for the wet, moss-prone conditions we deal with here in Whatcom County, they ask a homeowner to take on maintenance and moisture risk we'd rather not put on your house.
Vinyl can warp and fade, and its seams rely entirely on lap and overlap rather than a sealed, factory-finished surface. Engineered wood products like LP SmartSide perform well when detailed correctly, but they depend on field-applied caulking and paint staying intact at every cut edge — miss one spot during a wet winter and moisture finds its way in. Unfinished or primed wood siding needs the most ongoing attention of all, with repainting and edge-sealing on a recurring cycle that this climate makes hard to skip.
James Hardie fiber cement is non-combustible, dimensionally stable, and doesn't feed moss and mildew the way wood-based products can. The ColorPlus factory finish is baked on under controlled conditions rather than brushed on at the job site, which means better adhesion and a longer stretch before repainting is even a conversation. Hardie's HZ5 product line is engineered specifically for the freeze-thaw and moisture cycles of climates like ours, and the warranty is transferable if you sell the home — a real consideration in a market where buyers ask pointed questions about siding condition and age.
Full Exterior Work, One Local Crew
Siding rarely fails in isolation. Roofing, windows, and decks all share the same job — keeping water out of your house — and problems in one area often show up as damage in another. A roof that's shedding water onto a wall instead of into a gutter will accelerate siding failure regardless of what material is installed. A window that isn't flashed correctly will rot the wall cavity behind good siding just as easily as bad siding.
That's why we handle siding, roofing, windows, and decks as one connected exterior, not four separate trades that don't talk to each other. When we're on a Sumas property, we're looking at how water moves across the whole building — not just the wall section we were called out for.
What Working With a Local Crew Means
| Concern | Why It Matters in Sumas |
|---|---|
| Flashing and water management | Correct detailing at windows, trim, and butt joints is what actually keeps driving rain out — not the siding material alone |
| Ventilation behind siding | Proper rainscreen gaps let moisture that does get in dry out instead of sitting against the wall |
| Familiarity with local permitting | Whatcom County jurisdictions each have their own process, and knowing it in advance keeps a project on schedule |
| Long-term accountability | A crew based in the area is still around if a question comes up years after installation |
If your Sumas home is showing signs of wear — soft spots, peeling paint, moss buildup, or siding that's simply reached the end of its service life — we'd be glad to take a look. Reach out for a free, no-pressure estimate using the form below, and we'll walk you through what we see and what your options are.