Custer Exterior Work Built for Sumas Homes
Sumas sits in a part of Whatcom County where the weather doesn't do anything halfway. Homes here see long stretches of driving rain, damp air that never fully clears, and a moss and algae season that can stretch across most of the year. That combination is hard on exterior materials, and it's the reason we approach every project in this area the way we do: with materials and installation methods chosen specifically for what Pacific Northwest weather actually does to a house over time, not just how a product looks on day one.
Custer Siding works throughout the Sumas area on siding, roofing, windows, and decks. We're a local crew, which means we're not guessing at what this climate does to a home — we see it in the field year-round, on tear-offs, re-sides, and repair calls.
What Whatcom County Weather Does to a House
The moisture load in this region is the central issue. Rain doesn't just fall here — it drives sideways into wall assemblies during storms, and it lingers in shaded, north-facing, and tree-covered areas of a property for days after a storm passes. Add in the region's naturally high humidity and you get conditions where moss, algae, and mildew take hold on exterior surfaces far faster than they would in a drier climate.
- Moisture intrusion: Repeated wetting and drying cycles stress seams, caulk joints, and any material that swells or absorbs water.
- Moss and algae growth: Shaded siding, roof valleys, and north-facing walls stay damp longer, giving organic growth a longer season to establish itself.
- Salt and coastal air influence: Whatcom County's proximity to marine air adds a corrosive element that accelerates wear on fasteners, trim, and lower-grade siding materials.
- UV and freeze-thaw cycling: Even with cloud cover, seasonal temperature swings put ongoing stress on caulking and material joints.
None of this is unusual for the area — it's just the reality of building and maintaining a home in this part of Washington. What matters is choosing materials and installation details that are designed to hold up to it.
Why We Only Install James Hardie Siding
We made a deliberate decision years ago to install James Hardie fiber cement siding exclusively — not vinyl, not LP SmartSide, not primed wood, not cedar. That's not a marketing angle; it's a standard we hold because of what we've seen this climate do to other materials over time.
Vinyl siding can warp and become brittle with UV and temperature swings, and its seams give moisture more opportunities to find a way behind the cladding. Wood-based products, including engineered wood siding, depend on an intact factory coating and careful field sealing at every cut edge — miss one spot in a climate this wet, and moisture finds it. Cedar is a beautiful, traditional choice, but it requires ongoing maintenance — staining, sealing, and monitoring — to hold up against constant damp exposure and moss growth, and that upkeep burden only grows in a climate like this.
James Hardie fiber cement is engineered differently. It's non-combustible, dimensionally stable, and available in HZ product lines specifically formulated for regions with heavy moisture exposure. The factory-applied ColorPlus finish is baked on and resists fading, cracking, and peeling far longer than field-applied paint systems, which matters a great deal in an area where a house rarely gets a long dry stretch to properly cure fresh paint. Hardie also backs its products with a strong transferable warranty, which protects the investment for the homeowner, not just the original buyer.
None of this means other products are without merit — they simply come with maintenance schedules and moisture-management requirements that we don't think make sense to ask a Sumas homeowner to take on, given what this climate demands.
Siding, Roofing, Windows, and Decks — One Local Crew
Most of the exterior problems we see in this region don't come from one bad material — they come from gaps between systems: a roof that isn't properly flashed into the siding, a window that isn't correctly integrated with the water-resistive barrier, a deck ledger board that traps moisture against the house. Because we handle siding, roofing, windows, and decks as one crew, we can look at a home's exterior as a single connected system rather than a set of separate trades, which matters when the goal is keeping water out for good.
For roofing, that means materials and flashing details suited to sustained rain exposure. For windows, it means correct flashing and sealing at the rough opening so water is directed out, not in. For decks, it means selecting materials and structural details that hold up to constant dampness and shade without becoming a moss trap or a rot risk.
A Local Crew Matters Here
Working in Whatcom County day in and day out means we've watched how homes in and around Sumas actually age — where moss establishes first, which sides of a house take the worst weather, and where past installations (regardless of material) tend to fail first. That local, hands-on knowledge shapes how we detail every project, not just which siding brand we put on the wall.
If you're planning a siding, roofing, window, or deck project in Sumas, we're happy to take a look and talk through what your home actually needs. Reach out for a free, no-pressure estimate — there's no obligation, just an honest assessment from a local crew that works in this climate every day.