Ferndale Roofing The Shingles Get the Credit, But They're Not the Whole Story
When people think about their roof, they picture the shingles — the color, the texture, the brand. But shingles are really just the visible skin. The parts doing the heavy lifting against water intrusion are underneath and around them: the underlayment, the flashing, and the details at every edge, valley, and penetration. In Ferndale and the rest of Whatcom County, where salt air off the Strait of Georgia, driving winter rain, and a long moss season all put steady pressure on a roof system, those hidden layers often determine whether a roof lasts fifteen years or thirty.
What Underlayment Actually Does
Underlayment is the water-resistant layer installed directly on the roof deck, before shingles ever go down. Its job is simple but critical: if wind-driven rain gets past the shingles — which happens more often than people assume in a coastal wind pattern like ours — the underlayment is the backup that keeps the deck dry.
- Felt paper is the traditional option. It's inexpensive and has a long track record, but it can wrinkle when it gets wet and tears more easily during installation.
- Synthetic underlayment is more tear-resistant, sheds water better during the install process itself (useful when a job spans more than one dry window, which is common here), and holds up longer under UV exposure if it's left exposed for a few days.
- Self-adhered membrane (ice-and-water type products) gets used in specific high-risk zones — eaves, valleys, around chimneys — rather than across the whole roof, because it's a different tool for a different problem.
None of these is automatically "the right one" for every roof. The right choice depends on the roof's slope, the shingle product going over it, and how exposed the deck will be during construction.
Flashing: Where Most Leaks Actually Start
If you ask most roofers where leaks originate, the honest answer is almost never "in the middle of a flat shingle field." It's at the transitions — where a roof plane meets a wall, a chimney, a skylight, or another roof plane. That's flashing's job: metal (or sometimes rubber) formed to shed water at exactly those seams.
Common flashing points worth understanding:
- Step flashing along walls and dormers — individual pieces woven in with each course of shingles, not one long strip caulked over the top.
- Valley flashing where two roof slopes meet, which carries a concentrated volume of water during heavy rain events.
- Chimney and skylight flashing, which needs to accommodate a rigid object sitting in the middle of a roof plane that expands, contracts, and moves slightly with temperature and moisture.
- Kickout flashing at the bottom of a wall-roof intersection, directing water into the gutter instead of behind the siding — a small detail that's frequently skipped and causes slow, hidden rot over years.
Caulk and roofing cement have their place, but they're a maintenance item, not a substitute for correctly formed and layered flashing. A roof that depends on sealant to stay dry is a roof that will eventually leak once that sealant ages, shrinks, or gets missed on a maintenance visit.
Why This Matters More Here Than in a Dry Climate
Whatcom County doesn't get occasional hard rain — it gets sustained, wind-driven rain across long stretches of fall and winter, often from a direction that pushes water sideways into laps and seams rather than straight down. Add in salt-laden air moving inland from the coast, which accelerates corrosion on lower-grade metal flashing and fasteners, and you have conditions that expose weak underlayment or poorly detailed flashing faster than they would in a milder or drier region. Moss is part of this picture too — a long moss season means organic growth holding moisture against the roof surface for months at a time, which puts extra strain on any flashing or underlayment that was installed as an afterthought rather than a priority.
What This Means When You're Getting a Roof Quoted
A roof estimate that only talks about shingle brand and color is leaving out half the conversation. Questions worth asking any contractor include:
- What underlayment are you using, and why that one for this roof specifically?
- How are you handling step flashing at walls and dormers — new metal, or reusing what's there?
- What's the plan for valleys, and is kickout flashing included at wall-roof intersections?
- What metal or material is being used for flashing, and how does it hold up to coastal air over time?
These aren't trick questions. They're the difference between a roof that's built to shed water for decades and one that looks fine until the first hard windstorm finds the weak point.
Our Standard
Our approach is to treat flashing and underlayment as the actual waterproofing system, with shingles as the outer layer on top of it — not the other way around. That means proper step flashing woven into each course, correctly lapped underlayment matched to the roof's exposure and slope, and attention to the small details like kickouts and valley metal that don't show up in a curb-side photo but show up in a roof's lifespan.
If you're planning a re-roof or just want a straight answer about what's going on under your current shingles, we're happy to take a look. We offer free, no-pressure estimates for homeowners in Ferndale and throughout Whatcom County — reach out using the form below.