9 Roof Maintenance Tasks to Do Every Fall
In the San Juan Islands, fall is the deadline. The heaviest rain arrives in November, wind pushes across the water harder on the west-facing slopes, and the roof you ignored all summer is about to be tested by roughly 40 inches of annual rainfall concentrated into the wet months. A weekend of maintenance now is the cheapest insurance you'll ever buy — a small repair caught in October costs a fraction of the interior damage a missed one causes in January. Here are the nine tasks worth doing before the storms settle in.
1. Clear the Gutters and Downspouts
Under the Douglas firs, gutters fill with needles and leaves that turn into a soggy dam. Blocked gutters overflow behind the fascia, rot the eave, and in a cold snap force water back under the shingles. Flush every run, confirm downspouts drain well away from the foundation, and check that hangers are still tight. This is the single highest-return task on the list.
2. Treat and Remove Moss on Shaded Slopes
Moss thrives on the north-facing slopes that sit in shade beneath the trees. It holds moisture against the roofing, lifts shingle edges, and shortens roof life. Fall is the time to treat it — before the growth explodes in the wet season.
Do not pressure-wash asphalt shingles; it strips the protective granules. Use a gentle treatment and let the rain rinse it. Budget an estimate, not a quote, of $400–$1,600 for professional moss treatment depending on roof size and severity. Installing zinc or copper ridge strips at the same time releases metal ions that slow regrowth for years.
3. Inspect and Reseal Flashing
Flashing — the metal at valleys, chimneys, skylights, and wall intersections — is where most island leaks actually start, not in the open field of the roof. Check for lifted edges, cracked sealant, and corrosion. Near saltwater, look hard for rust on fasteners and flashing metal, and confirm dissimilar metals aren't reacting. Reseal or replace anything questionable now.
4. Check Fasteners, Especially Near Saltwater
Salt air corrodes cheap fasteners from the inside out. On metal roofs, walk the slopes and look for rust streaking below screw heads, backed-out screws, and hardened washers. On any roof within sight of saltwater, corroded fasteners are a leading cause of premature failure. Replace failing ones with stainless, corrosion-resistant hardware rather than matching the original builder-grade screws.
5. Look for Damaged, Lifted, or Missing Shingles
Wind is stronger on the west side — roughly 20 percent stronger than across the water in Anacortes — so summer gusts may have already loosened material. From the ground with binoculars and, safely, from a ladder, scan for cracked, curled, lifted, or missing shingles and any exposed nail heads. Small shingle repairs run an estimate of $450–$3,500; letting them ride into November is how they become a full-slope problem.
6. Verify Valleys and Eaves Are Protected
Valleys concentrate water, and eaves are where ice and backed-up water do their damage. Ice-and-water membrane belongs at both. If your roof predates modern underlayment standards or you've had eave leaks before, this is the detail to confirm — because researching https://cruzefzi848.rivetgarden.com/posts/how-to-find-and-fix-a-roof-leak won't help if the water is already getting under the shingles at the most vulnerable points. Anywhere you see staining below a valley or eave, investigate before the wet season.
7. Trim Overhanging Branches
Douglas fir and cedar limbs that scrape the roof abrade the surface, drop debris that feeds moss, and become projectiles in a windstorm. Cut branches back so they clear the roof by several feet. This also opens shaded slopes to a little more light and air, which slows moss naturally.
8. Inspect the Attic From Inside
The best view of roof health is often from below. On a rainy day, go into the attic with a flashlight and look for daylight through the deck, water stains on the sheathing, damp or matted insulation, and any musty smell that signals trapped moisture. Confirm attic vents are clear — good ventilation keeps the deck dry and discourages condensation that mimics a leak.
9. Confirm Your Emergency and Documentation Plan
Storm damage happens even to well-maintained roofs. Before November, know where your tarps and buckets are, photograph the roof in its current sound condition (dated photos help any future insurance claim), and keep a record of the maintenance you've done. That documentation proves the roof was healthy before a storm — the line between a covered claim and a "deferred maintenance" denial.
Fall Maintenance Checklist at a Glance
Task Priority DIY or Pro Rough Cost (estimate, not a quote) Clear gutters & downspouts High DIY / Pro $ — mostly time Treat/remove moss High Pro recommended $400–$1,600 Inspect & reseal flashing High Pro Repair $450–$3,500 Check fasteners near saltwater High Pro Included in repair scope Fix damaged/missing shingles High Pro $450–$3,500 Verify valley/eave membrane Medium Pro Varies Trim overhanging branches Medium DIY / Arborist $ — labor Inspect attic from inside Medium DIY Free Confirm emergency plan & photos Low DIY FreeA Note on Island Timing and Cost
Getting a crew and materials out to the islands adds roughly 10 to 25 percent over a comparable mainland job once ferry staging and off-island disposal are factored in. That premium is another reason to schedule non-emergency work in early fall rather than in a January downpour — you'll have your pick of dates, and you won't be paying rush logistics to fix something a $20 tube of sealant could have prevented in October.
The Bottom Line
None of these nine tasks is glamorous, and most cost little more than a Saturday and a ladder. But in a climate this wet, this windy, and this salty, fall maintenance is what separates a roof that quietly does its job for decades from one that fails at the worst possible moment. Work down the list before the November rains, and you'll spend the wet season dry.
About the Author
Ted Halloran is a home-maintenance writer and former general contractor who has cared for houses across the rainy Pacific Northwest for over two decades. He specializes in practical, seasonal upkeep for high-moisture coastal climates.