Birch Bay Roofing Board & Batten Siding for Sumas Homes
Board and batten is one of the most requested siding styles we install in the Sumas area, and for good reason. The look is clean and distinctly Pacific Northwest — wide vertical boards with narrow battens covering each seam, giving a home strong vertical lines and a rugged, cabin-meets-modern character that works on everything from a full exterior to an accent gable or entry feature. But the style that makes board and batten attractive is also the style that makes it unforgiving if it's built wrong. Every seam is a vertical channel that water can travel down, and in a climate like ours, that detail matters more than most homeowners realize until something goes wrong behind the wall.
We install board and batten for Sumas homeowners using James Hardie fiber cement exclusively. This page walks through what the local climate actually does to this style of siding, what a correct installation involves, and why the details we insist on aren't optional extras — they're what keeps a board and batten exterior looking sharp for decades instead of five to seven years.
What Whatcom County's Climate Does to Vertical Siding
Sumas sits in a part of Whatcom County that deals with a specific combination of weather stress: salt-laden air moving in off the Sound, long stretches of driving, wind-blown rain rather than gentle vertical rainfall, and a moss and mildew season that can run most of the year in shaded or north-facing exposures. Each of these has a distinct effect on board and batten siding.
Salt Air and Fastener Corrosion
Salt air accelerates corrosion on any exposed or marginal metal fastener. On board and batten specifically, the battens are face-nailed or blind-nailed in a long vertical run, which means there are more total fastener penetrations per square foot than on horizontal lap siding. If the wrong fastener is used, or fasteners are placed where they'll stay damp, corrosion shows up as rust streaking down the face of the siding within a few seasons — a cosmetic problem that's really a sign of a materials mistake.
Driving Rain and Vertical Water Paths
Wind-driven rain doesn't fall straight down here — it gets pushed sideways and upward under eaves and around corners. Board and batten's vertical joints give water a direct path down the wall if the gaps, laps, and flashing details aren't correct. Horizontal lap siding sheds water outward at every course; vertical board and batten depends entirely on the quality of the seams and the drainage plane behind the boards to do that same job.
Moss Season and Sustained Moisture
Long moss season means many exterior surfaces in this region stay damp for extended stretches, especially on shaded elevations and under tree cover common around Sumas properties. Untreated wood battens and boards hold that moisture, feeding moss, algae, and eventually rot at the board edges and batten strips. Any siding installed here needs a finish and substrate that resists that biological growth, not just a coating that looks good on day one.
Wood vs. Fiber Cement Board & Batten
Traditional board and batten was almost always wood, and a lot of homes in this region still have it. It's worth understanding honestly what that trade-off looks like next to James Hardie fiber cement before deciding what to put back on a wall.
| Factor | Wood Board & Batten | James Hardie Fiber Cement |
|---|---|---|
| Moisture absorption | Absorbs and swells; edges and battens rot first | Engineered to resist moisture-driven warping and swelling |
| Moss and mildew resistance | Low — needs regular cleaning and re-coating | ColorPlus factory finish resists mildew growth better than field-applied paint |
| Repainting cycle | Every 3–5 years in this climate | ColorPlus finish holds color for years longer with far less upkeep |
| Fire resistance | Combustible | Non-combustible fiber cement |
| Insect vulnerability | Vulnerable to carpenter ants and rot-driven insect damage | Not a food source for insects |
| Long-term cost | Lower upfront, higher lifetime maintenance cost | Higher upfront, lower lifetime maintenance cost |
We don't install wood board and batten, LP SmartSide, vinyl vertical panel, Cemplank, or Allura on Sumas homes. That's a standard we hold across every job, not a sales pitch specific to this page — we've made the call that James Hardie's engineered fiber cement is the only product we're willing to put our name behind in this climate, and board and batten is exactly the style where that decision matters most.
What a Correct Board & Batten Installation Involves
The visual style of board and batten is simple. The water management behind it is not. Here's what we consider non-negotiable on every board and batten job in this area.
Drainage Plane and Rainscreen Gap
A weather-resistant barrier goes over the sheathing first, and we build in a drainage gap behind the boards so any moisture that does get past the face can drain and dry rather than sitting against the wall assembly. This matters more on vertical siding than horizontal, because vertical seams create more direct paths inward if that gap isn't there.
Board and Batten Spacing and Fastening
James Hardie specifies exact gap widths between boards and precise fastening patterns for both the boards and the battens covering the seams. Too tight a gap and the assembly can't handle seasonal movement; too wide and you lose water protection at the joint. Fasteners have to land in framing or proper backing, at the right distance from board edges, using corrosion-resistant fasteners rated for this environment.
Flashing at Every Transition
Windows, doors, roof lines, and horizontal trim bands are where board and batten installations most commonly fail. Each of these transitions needs proper flashing integrated with the water-resistive barrier — not just caulk bridging a gap. Caulk fails; flashing sheds water by geometry and lasts.
Factory-Finished Edges
Every cut edge of a Hardie board should be sealed with the manufacturer-approved edge sealer before installation, especially at butt joints and batten overlaps. Skipping this step is one of the most common shortcuts that leads to premature swelling and paint failure at the seams, exactly where board and batten is most exposed.
Our Process for a Sumas Board & Batten Project
We keep this process consistent regardless of whether a job is a full re-side or an accent application on gables and entries.
- On-site assessment: we look at existing siding, sheathing condition, moisture history, and how the specific elevations face prevailing wind and rain.
- Tear-off and sheathing inspection: old siding comes off and we check for rot, hidden moisture damage, or compromised sheathing before anything new goes up.
- Water-resistive barrier and rainscreen installation: the drainage plane goes in correctly before a single board is hung.
- Board and batten installation to Hardie spec: proper spacing, fastening, and edge sealing at every board and every batten.
- Flashing and trim integration: windows, doors, and transitions are flashed and detailed before final trim goes on.
- Final walkthrough: we inspect every seam, fastener line, and transition with the homeowner before calling the job complete.
Maintaining Board & Batten Siding in This Climate
Even with the right product installed correctly, board and batten siding in a salt-air, high-moisture environment benefits from a few basic maintenance habits.
- Rinse salt residue and grime off the siding a couple of times a year, especially on elevations facing open water or prevailing wind.
- Trim back vegetation and tree cover that keeps any wall shaded and damp longer than it needs to be, since that's where moss takes hold first.
- Inspect caulking at window and door transitions annually and have any cracked or shrunk sealant redone promptly.
- Watch batten seams for any staining or discoloration, which is often the first visible sign of a fastener or flashing issue.
- Keep gutters and downspouts clear so overflow doesn't run down the face of vertical siding at concentrated points.
Why Local Experience with Sumas Homes Matters
Board and batten failures we're called to repair on other companies' installs almost always trace back to the same handful of shortcuts: no rainscreen gap, wrong fastener spacing, missing edge sealer, or flashing that was caulked instead of properly integrated. None of those mistakes are visible on installation day. They show up two, five, or ten years later as swelling, staining, or soft spots at the seams — usually right when a homeowner assumed the siding was maintenance-free.
A crew that regularly works in Sumas and the surrounding Birch Bay area understands how the specific combination of salt air, driving rain, and prolonged damp shade plays out on this style of siding, because we've seen what happens when those factors are ignored. That's the difference between a board and batten exterior that still looks sharp after a decade of Whatcom County winters and one that needs seam repairs before the original warranty period is even up.
Get a Straight Answer on Your Project
If you're considering board and batten siding for a home in the Sumas area, we're glad to take a look and give you an honest assessment of what your walls actually need, with no pressure and no inflated scope. Request a free estimate below and we'll walk the property, answer your questions, and tell you plainly what a correct job looks like for your home.