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Peaks &Valleys

Cornerstone guide

The PNW Roof Maintenance Calendar: What to Do, When, and What It Buys You

The Peaks & Valleys field teamWritten by the crews and inspectors on the roofs
Guide3 min readLast reviewed August 2, 2026How we research

The short answer

PNW roofs need a fall clean-out (gutters, debris, visual check) before the November storms, a spring inspection after winter's damage is done, moss treatment every 2–3 years, and a professional inspection every 2 years or after any major storm. Total cost: a few hundred dollars a year. Payoff: roughly 5 extra years on a $20,000 asset.

A 20-year roof and a 25-year roof are usually the same roof — one was maintained. Here is the entire calendar, honestly costed, for Washington and Oregon homes. Nothing on this list requires you on a ladder; most of it is a walk around the yard and two phone calls a year.

October — the one that matters most

The November storm season is the PNW roofing year’s main event, and October is your last calm month before it. Before the first big front:

  • Gutters and downspouts cleared — full gutters overflow at the eave, soak the fascia, and start ice dams east of the mountains. If you’re on the ladder twice a year and tired of it, micro-mesh guards retire the chore for good.
  • Debris off the roof — needle mats in valleys hold water against the exact seams that keep it out.
  • Ground-level visual check — curled tabs, dark exposure lines, anything crooked. Ten minutes with your phone camera; the photos become your before/after baseline if a storm hits.
  • Trees trimmed to clearance — limbs that touch the roof abrade it every windy night, and they’re the moss superhighway.

November–February — storm season protocol

Nothing scheduled — this is response season. After any storm with real wind: walk the yard, look for shingle pieces and granule piles, photograph anything suspicious within days (wind-lifted shingles reseal in warm spells and hide the evidence). Spokane-side homes: watch for icicles — they’re the attic warning light, not a decoration.

March–April — the damage audit

Winter’s bill arrives in spring. One walk-around: flashing lines straight? Ridge caps intact? Gutter seams weeping? Interior check of ceilings and attic (musty smell = ventilation problem). Every second spring — or every spring for roofs past 15 — make this a professional inspection. Ours are free, photographed, and plenty conclude “you’re fine,” which is the point of an audit.

May–June — moss treatment window

Late spring is the sweet spot for soft-wash moss treatment: growth is active (treatments work best on growing moss) and summer weather sheds the dead material. Every 2–3 years for most homes, every 2 under heavy canopy. Never pressure washing — here’s why that ruins roofs.

July–September — the project window

Dry season is when planned work happens on your schedule instead of a leak’s: replacements, ventilation corrections, skylight reseals, and the repairs spring’s audit found. Contractors’ calendars fill by June — homeowners who inspected in April pick their week; homeowners who waited for October’s first leak join a queue in the rain.

The math, plainly

Habit Cost What it buys
Fall clean-out (DIY or ~$150–$350 hired) ~$300/yr Prevents eave rot, ice dams, overflow damage
Moss treatment every 2–3 yrs ~$450–$1,200 Stops the #1 PNW shingle killer
Professional inspection every 2 yrs Free (ours) Catches $600 problems before they’re $6,000
Post-storm photo walk Free Preserves insurance evidence before it fades

Call it a few hundred dollars a year against a $12,000–$28,000 asset — and the difference between replacing at year 20 and year 25 is worth roughly $4,000–$7,000 in deferred cost alone. Maintenance isn’t a chore the roof demands; it’s the highest-yield investment the roof offers.

Want the calendar running without thinking about it? Book the free inspection and ask for the maintenance schedule — we’ll put your roof’s specific version in writing.

Peaks & Valleys crew soft-wash treating a moss-covered roof instead of replacing itSee it on a real jobMoss-Choked Roof Restored, Not ReplacedBothell, WA · A Bothell home shaded by mature firs had moss thick enough to hold moisture year-round. Another bid called for full replacement. The shingles underneath had life left.

Sources & methodology

Insurance, permit and code details vary by policy and jurisdiction. This guide is general information from our field experience, not individualized professional advice.

Questions homeowners actually ask

What's the single most important roof-maintenance task in the PNW?

Clearing gutters and roof debris before the November storm season. Full gutters overflow at the eave, soak the fascia, and start ice dams east of the mountains; needle mats in valleys hold water against the exact seams meant to keep it out. It's the cheapest task with the biggest payoff.

How often should I have my roof professionally inspected?

Every two years for most roofs, every spring once a roof passes 15 years, and after any major storm. Ours are free and photographed, and plenty conclude 'you're fine' — which is the whole point of an audit: catching a $600 problem before it becomes a $6,000 one.

Does roof maintenance actually extend the roof's life?

Yes — a 20-year roof and a 25-year roof are usually the same roof; one was maintained. For a few hundred dollars a year against a $12,000–$28,000 asset, deferring replacement from year 20 to year 25 is worth roughly $4,000–$7,000. It's the highest-yield investment the roof offers.

Everything in this series

The supporting guides under this cornerstone.

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