Birch Bay Exterior Board & Batten Siding, Done Right, for Sumas-Area Homes
Board and batten has become one of the most requested siding looks in Whatcom County — the clean vertical lines read as modern farmhouse on a new build and as understated and classic on an older one. It's a style choice, but out here it's also a performance decision. Homes in and around Sumas and the broader Birch Bay service area deal with long stretches of wet weather, humid air that lingers in low spots, and a moss season that can run most of the year if a house isn't detailed to shed water and dry out between storms. Board and batten looks simple from the curb. Installed correctly, it's actually a more exacting job than lap siding, and installed poorly, it's one of the faster ways to trap moisture behind a wall.
This page is specific to board and batten siding for the Sumas area. We're not going to give you a generic rundown of siding styles — we're going to walk through what this particular look needs to hold up here, what a correct installation actually involves, and why we install it exclusively in James Hardie fiber cement rather than the wood, vinyl, or engineered-wood versions of the same look.
Why This Climate Changes How Board & Batten Should Be Built
Whatcom County's mix of driving rain, salt-tinged marine air near the coast, and heavy moss pressure inland means vertical siding systems take on water differently than lap siding does. Board and batten relies on the seams between boards and battens to stay tight and to let any moisture that does get behind them find a way back out. In a dry climate, a mediocre installation might go years without showing a problem. In a climate where the siding rarely gets a long uninterrupted dry stretch, the same shortcuts show up much sooner — as staining at the battens, soft spots at the base, or moss and algae taking hold in the vertical channels where water sits longest.
That's the backdrop for every decision below: fastening pattern, gap sizing, flashing details, and drainage plane. None of it is exotic. It's just not optional here.
What Homeowners Usually Notice First
- Dark streaking or green/black growth concentrated at the battens or board seams
- Soft or discolored siding near the bottom courses, close to grade or a deck ledger
- Paint or caulk failing faster at vertical seams than on the rest of the house
- Visible gaps opening up at butt joints as boards move with seasonal moisture swings
- A house that looks fine from the street but has moss building up on the north or shaded elevation
What a Correct Board & Batten Installation Actually Involves
Board and batten is unforgiving of shortcuts because the batten strips cover the vertical seams — which means a lot of what makes the job right or wrong is hidden the moment installation finishes. A few things we won't skip, regardless of what a homeowner may have seen done elsewhere:
- A drainage plane behind the siding — furring strips or a rain screen gap so any moisture that gets past the surface has somewhere to go besides the sheathing
- Correct fastener placement and spacing — through both the board and the batten into framing, following the manufacturer's fastening schedule rather than "close enough"
- Proper gapping at butt joints — fiber cement expands and contracts with moisture and temperature; joints need room to move without buckling or opening a gap you can see daylight through
- Flashing at every horizontal transition — window heads, water tables, roof-to-wall intersections, and the base of the wall, so water is directed out and away rather than behind the panel
- Factory-cut and factory-primed edges wherever possible, with any field cuts sealed per manufacturer spec — an unsealed cut edge is one of the fastest ways fiber cement takes on water it wasn't designed to handle
None of this is visible once the job is buttoned up. It's the difference between siding that looks good in photos on day one and siding that still looks good — and is still dry behind the wall — ten years in.
The James Hardie Board & Batten System — What We Install
We install James Hardie fiber cement exclusively, and board and batten is one of the styles where that decision matters most. Hardie's vertical siding system (HardiePanel vertical siding paired with Hardie battens, or engineered board and batten profiles depending on the look a homeowner wants) is manufactured as a matched system — the panel, the batten, and the fastening approach are designed to work together, rather than a field-improvised combination of unrelated products.
A few specifics worth knowing:
- Non-combustible fiber cement core — doesn't feed a fire the way wood-based sidings can
- Climate-engineered HZ formulation for the Pacific Northwest, built around moisture exposure rather than a one-size-fits-all national spec
- ColorPlus factory finish — a baked-on finish applied and cured under controlled conditions, which holds color and resists fading and moisture intrusion at the surface far better than a field-applied paint job, and comes with its own finish warranty
- Strong transferable manufacturer warranty when the system is installed to Hardie's published specifications — which is exactly why we follow those specs to the letter rather than treating them as a suggestion
We don't install LP SmartSide, vinyl board and batten, Cemplank, Allura, or primed wood versions of this look. That's not a knock on every homeowner who has one of those products on their house today — it's that after years of doing this work in this climate, we standardized on one system we can stand behind fully, including the warranty behind it.
Board & Batten Material Options Compared
| Material | How It Handles This Climate | Long-Term Maintenance | Fire Performance |
|---|---|---|---|
| James Hardie fiber cement | Engineered for Pacific Northwest moisture; stable when installed to spec | Low — ColorPlus finish resists fading and doesn't need repainting on the same cycle as wood | Non-combustible core |
| Primed wood or cedar | Attractive but absorbs moisture readily; prone to swelling, cupping, and rot in wet seasons | High — repainting, caulking, and rot repair on a recurring cycle | Combustible |
| Vinyl board and batten | Won't rot, but can trap moisture behind it and distorts in heat; seams are a weak point | Low upfront, but limited repair options once damaged or faded | Can soften/melt at lower temperatures than fiber cement |
| Engineered wood (e.g. LP-type) | Better moisture resistance than raw wood, but the wood-strand core is still moisture-sensitive at cut edges and joints | Moderate — edge sealing and joint maintenance matter more than with fiber cement | Combustible |
This is a general comparison of the category, not a claim about any specific competitor's product line — but it's the honest reasoning behind why our crews only carry Hardie onto a roof or wall in this climate.
Our Process for a Sumas-Area Board & Batten Project
- On-site assessment — we look at the existing siding, sheathing condition, and any signs of past moisture intrusion before quoting anything
- Moisture and drainage check — grading, gutter performance, and any spots where water currently sits against the house get flagged and addressed as part of the plan, not left as someone else's problem
- Removal and sheathing inspection — once old siding is off, we check the sheathing itself; hidden rot gets repaired before anything new goes on, not covered over
- Rain screen / drainage plane installation — furring strips set to allow airflow and drainage behind the new siding
- Hardie board and batten installation — panels and battens installed per manufacturer fastening schedule, with flashing detailed at every transition
- Final inspection and cleanup — a walk-through so the homeowner sees the finished work and understands what was done and why
Maintenance in a Moss-Prone Climate
Fiber cement board and batten with a ColorPlus finish is low-maintenance, not no-maintenance. A few habits go a long way in a region where moss and algae growth is a near-constant pressure:
- Rinse siding (garden hose pressure, not a pressure washer aimed directly at seams) once or twice a year to clear organic buildup before it takes hold
- Keep gutters clear so overflow isn't running down the wall and feeding growth at the battens
- Trim back vegetation and tree cover that keeps a wall shaded and damp longer than the rest of the house
- Have caulking at trim and window transitions checked periodically — caulk is a maintenance item even when the siding underneath isn't
Signs Your Current Siding Should Be Evaluated
- Visible gaps, warping, or separation at board and batten seams
- Soft siding when pressed near the base of the wall or below windows
- Persistent moss or algae that returns quickly after cleaning
- Peeling or bubbling paint, especially concentrated at vertical joints
- Interior signs like musty smell or staining on walls that back up to exterior siding
Why It Matters to Hire a Crew That Already Works This Area
Board and batten done wrong doesn't usually fail in year one — it fails in year five or eight, after the warranty conversation has been forgotten and the homeowner is left sorting out whether it's a manufacturer issue or an installation issue. A crew that works Sumas and the surrounding Birch Bay area regularly has already seen how this climate treats different fastening patterns, gap sizes, and flashing details over real winters, not just in a training manual. That's the difference between a crew that can install fiber cement and a crew that installs it correctly for where it's actually going.
If you're considering board and batten siding for a home in the Sumas area, we're happy to take a look and talk through what your specific house needs — no pressure, no obligation. Fill out the form below for a free estimate.