Birch Bay Siding Exterior Work Built for Sumas Homes
Sumas sits in a part of Whatcom County where the weather doesn't do anything halfway. Winters bring long stretches of rain and fog, spring and fall track heavy moisture off the surrounding hills and valleys, and moss finds a foothold on almost any exterior surface that stays shaded and damp for more than a few weeks at a time. Add in the seasonal humidity that settles into this part of the county, and you've got a climate that is genuinely hard on siding, trim, roofing, and anything else on the outside of a house. Birch Bay Siding Company works throughout Whatcom County, and Sumas homes get the same attention to moisture management and material selection that we bring to every job.
What the Climate Does to a House Out Here
The biggest issue for homes in this area isn't one dramatic storm — it's the cumulative effect of being wet, or nearly wet, for a large part of the year. That shows up as:
- Moss and algae growth on north-facing walls, under eaves, and anywhere sunlight and airflow are limited.
- Paint and caulk failure where wood or composite siding has been repeatedly soaked and dried, cracking the surface film that's supposed to keep water out.
- Swelling, delamination, or soft spots in siding products that weren't engineered to handle sustained moisture exposure.
- Roof and gutter strain from prolonged rain events that test flashing details and drainage far more than an occasional heavy storm would.
None of this is unique to any one street or subdivision in Sumas — it's the nature of exterior work anywhere in this part of Whatcom County. The difference is in how a house is built and maintained to handle it.
Why We Install James Hardie — and Nothing Else
Birch Bay Siding Company installs James Hardie fiber cement siding exclusively. We don't offer vinyl, LP SmartSide, Cemplank, Allura, primed spruce, or cedar, and that's a deliberate call based on what holds up in this climate over the long run.
Wood-based and wood-composite siding products can perform well when maintained perfectly, but "perfectly maintained" is a high bar in a climate that keeps surfaces damp for months at a stretch. Once moisture gets past a compromised paint layer or a poorly sealed joint, wood-based products are prone to swelling and softening at the edges — and by the time it's visible, the damage is often already underway. Vinyl sidesteps the rot issue but has its own limitations: it can warp or fade with prolonged UV and temperature swings, and it doesn't hold paint if a homeowner ever wants to change the color down the road.
James Hardie fiber cement is cement, sand, and cellulose fiber — it doesn't absorb water the way wood-based products do, and it isn't vulnerable to swelling or rot from constant damp exposure. It's also non-combustible, which matters given wildfire smoke and dry-season fire risk are now a factor even in wetter parts of Washington. Hardie's ColorPlus finish is baked on at the factory under controlled conditions, which gives a more durable, consistent topcoat than field-applied paint — a real advantage when a house is going to spend a good part of the year wet. And Hardie backs its products with a strong, transferable warranty, which matters to homeowners who plan to sell at some point down the line.
We also install Hardie's HZ5 product line, engineered specifically for regions with heavy moisture and freeze-thaw cycles — a good match for what Whatcom County winters actually deliver.
Full Exterior Services for Sumas
Siding is our specialty, but siding doesn't work in isolation. We handle the full exterior envelope, because a house is only as weather-tight as its weakest connection point:
- Siding installation and replacement — James Hardie fiber cement, installed to manufacturer spec with proper flashing, clearances, and fastening for this climate.
- Roofing — because a roof and its flashing details work together with siding to keep water out of the wall assembly.
- Windows — window openings are one of the most common places water finds its way behind siding if they aren't flashed and sealed correctly.
- Decks — built to shed water and hold up to the same rain and moisture load as the rest of the exterior.
Correct installation matters as much as the product itself. Fiber cement siding installed with the wrong gap, missing flashing, or fasteners driven incorrectly can still let water in — the material only performs as well as the crew putting it on the wall.
Why a Local Crew Matters
A crew that works this part of Whatcom County regularly knows what actually happens to a house here over five, ten, twenty years — not just what a spec sheet says. We know which details tend to fail first in this climate, we size up ventilation and moisture management with the region's weather in mind, and we're around after the job is done if something needs a look.
If you're weighing a siding replacement, a roof, new windows, or a deck for your Sumas home, we're happy to take a look and give you a straightforward, no-pressure estimate — just fill out the form below to get started.