Home Exterior Inspection Checklist for Guemes Island, Skagit County

Updated August 2026 · Alpine Exteriors · WA contractor license ALPINI751OW

Why This Checklist Matters in This Region

Guemes Island sits in Rosario Strait, reachable only by the Guemes Island Ferry out of Anacortes, and that isolation changes how homeowners here have to think about maintenance. A missed problem on a mainland Skagit County property is an inconvenience; a missed problem on Guemes can mean waiting on ferry schedules to get a contractor, a materials delivery, or even a ladder over to the house. Catching issues early, on your own schedule, is worth more here than almost anywhere else in the service area.

The island's exposure to open water also means homes take a steady diet of salt-laden air, especially on west- and north-facing elevations that catch wind off the Strait and the broader Salish Sea. Salt air accelerates corrosion on fasteners, flashing, gutter hangers, and any exposed metal trim faster than it would on a home twenty miles inland in Mount Vernon or Burlington. At the same time, Guemes shares the same wet-winter pattern as the rest of Skagit and Whatcom counties: long stretches of steady rain from November through March, punctuated by windstorms that push horizontal rain into siding and window assemblies that would stay dry in a calmer climate. Shaded, tree-covered lots on the island's interior grow moss and algae on north-facing roof slopes just as readily as similar lots in Sedro-Woolley or the wooded parts of Camano Island.

Homes here are also built and permitted under the Washington State Energy Code, which sets requirements for insulation, air sealing, and window performance. An exterior inspection is a good moment to notice where that envelope has started to fail — gaps, rot, or moisture intrusion that let conditioned air escape and outside moisture in, undermining the energy performance the home was designed to have. This checklist is meant to be walked once or twice a year, ideally in early fall before the wet season sets in and again in spring once storms have passed, so you catch problems while they're still small and inexpensive to fix.

The Checklist

Roof

• Moss and algae streaking on shaded or north-facing slopes — Guemes has plenty of tree cover, and moss holds moisture against shingles or shakes, shortening their life and working under the tab edges.
• Lifted, cracked, or missing shingles/shakes, especially on the windward (west/north) side — this is the side that takes the brunt of wind off the Strait and is most likely to show wind damage first.
• Rusted or lifting flashing around chimneys, vents, and valleys — salt air corrodes exposed metal faster than it would on a mainland home, so flashing here needs closer, more frequent attention.
• Granule buildup in gutters or at downspout outlets — heavy granule loss signals the roofing has aged past its protective coating and is losing waterproofing ability.
• Sagging roof deck or visible dips between rafters — can indicate long-term moisture intrusion or rot in the sheathing underneath, often invisible until you look for the sag from a distance.

Windows

• Fogging or condensation between panes on dual-pane units — the seal has failed and the insulating gas is gone, which hurts both comfort and the Washington State Energy Code performance the window was rated for when installed.
• Soft, discolored, or crumbling wood trim around frames — a sign that wind-driven rain has been getting behind the trim, a common issue on west-facing walls that catch storms directly.
• Difficulty opening, closing, or latching — frames can swell from moisture or shift slightly as the house settles; either way it's worth diagnosing before it gets worse.
• Cracked or failing caulk and sealant at the perimeter — gaps here let both bulk water and drafts through, undercutting the airtightness the energy code assumes.
• Corrosion on aluminum or metal window hardware — salt air speeds this up noticeably compared to inland homes in Mount Vernon or Burlington.

Siding and Trim

• Cracked, warped, or separating siding panels or boards — once a gap opens, wind-driven rain finds its way behind the siding and soaks the sheathing.
• Peeling paint or a chalky residue on painted surfaces — a normal sign of UV and salt exposure, but it also means the protective coat is thinning and moisture can start getting in underneath.
• Soft spots when pressed, especially near the ground and around window/door trim — soft wood usually means rot has already started, most often where water collects or splashes back off the ground.
• Visible fastener corrosion or staining streaks below nail heads — rust streaks running down siding are a direct sign that fasteners are corroding, which is more common here than on the mainland due to salt air.
• Gaps at corner boards, trim joints, and where siding meets the foundation — these are the most common entry points for both bulk water and pests.

Gutters and Downspouts

• Sagging sections or gutters pulling away from the fascia — usually caused by debris weight or failing hangers, and it lets water spill down the siding instead of into the downspout.
• Clogs from needles, leaves, and moss debris — heavily treed lots on the island tend to fill gutters faster than open lots, and overflow during heavy rain events can drive water into the fascia and soffit.
• Downspouts that don't extend water well away from the foundation — with Skagit County's wet winters, undirected downspout discharge is one of the most common causes of foundation moisture problems.
• Rust spots or pinholes in metal gutters — again, salt air accelerates this; check gutters on the windward side more often than the sheltered side.
• Standing water in gutters after rain has stopped — a sign of poor pitch or a blockage that needs clearing rather than just a cosmetic issue.

Decks and Outdoor Structures

• Soft or spongy deck boards, especially near the house or in shaded corners — moisture sits longest in these spots and rot progresses fastest there.
• Rust on fasteners, joist hangers, or railing hardware — coastal decks corrode noticeably faster; hardware rated for coastal exposure holds up much better here than standard interior-grade fasteners.
• Wobbly railings or loose posts — a safety issue as much as a maintenance one, and worth checking every season rather than waiting for a visible failure.
• Gaps or separation where the deck ledger attaches to the house — this connection carries structural load and needs to stay tight and properly flashed to keep water out of the band joist.
• Moss buildup on deck surfaces — beyond being slippery, trapped moss holds moisture against the wood the same way it does on a roof.

Foundation and Grading

• Cracks in the foundation wall wider than a hairline — most small cracks are cosmetic, but wider or growing cracks can indicate settling or hydrostatic pressure from wet soil.
• Grading that slopes toward the house instead of away from it — with the region's rainfall totals, poor grading is one of the more common causes of crawlspace and foundation moisture.
• Damp, musty smell or visible moisture in a crawlspace — often traceable to gutter discharge, grading, or vapor barrier gaps rather than the foundation itself.
• Efflorescence — a white, powdery mineral deposit on concrete or masonry — a sign that water has been moving through the material, even if the surface looks dry now.

What to Do If an Item Fails

Not every failed item is an emergency, and it's worth thinking about severity before you act. Cosmetic issues — chalky paint, minor moss on a deck, small hairline foundation cracks — are worth noting and monitoring, but they don't usually require immediate work. Functional issues, like a downspout dumping water at the foundation or a gap in trim caulking, should be corrected within the same season, ideally before the next heavy rain event, since Skagit County's wet months can turn a small gap into a much larger repair by spring. Structural or safety issues — a sagging roof deck, a loose deck railing, soft framing you can press a finger into, or an active leak — should be addressed promptly rather than left for the next inspection cycle.

For anything you can safely reach and diagnose from the ground or a stable ladder, simple fixes like clearing gutters, re-caulking a window perimeter, or redirecting a downspout extension are reasonable DIY tasks. Once an item involves roof access, structural framing, electrical proximity, or anything more than a few feet off the ground, it's worth weighing the risk of doing it yourself against the cost of having someone experienced handle it — especially on an island where a fall or an injury means a longer trip to get help.

When to Call a Professional

Some findings are worth a professional opinion even if they don't look urgent. Any sign of active water intrusion — staining on interior ceilings or walls that lines up with an exterior issue, a musty crawlspace, or a soft roof deck — deserves a proper assessment before it's patched over, since surface repairs on top of hidden rot rarely hold. Anything involving roof flashing, structural framing, deck ledger connections, or window and door integration with the building envelope is worth having inspected by someone who works on homes in this climate regularly, because the fix often needs to account for how wind-driven rain and salt air behave here specifically. If you're planning a larger project, such as replacing aging windows or re-siding a section of the home, that's also a good time to bring in a contractor rather than patching piecemeal, since coordinated work tends to hold up better against the next storm season than a series of one-off repairs.

Alpine Exteriors works with homeowners throughout Skagit, Island, and Whatcom counties — including Guemes Island, Anacortes, Mount Vernon, Burlington, Sedro-Woolley, La Conner, Stanwood, Camano Island, and Bellingham — on roofing, window, deck, and gutter work, and can help sort which items on this list are worth immediate attention versus ongoing monitoring. Because ferry logistics affect scheduling on Guemes, it's worth reaching out with some lead time rather than waiting until a problem is urgent.

FAQ

How often should I walk through this checklist on Guemes Island?

Twice a year is a reasonable baseline — once in early fall before the wet season builds, and once in spring after storms have passed — though homes with heavy tree cover or direct exposure to wind off the Strait may benefit from a quicker mid-winter check of gutters and roof drainage as well.

Does salt air really make that much difference compared to a mainland Skagit County home?

It's a real factor, particularly for exposed metal — flashing, gutter hardware, fasteners, and deck hardware tend to show corrosion sooner on Guemes and other coastal or island properties than on a similar home further inland in Mount Vernon or Sedro-Woolley, which is why coastal-rated fasteners and more frequent metal inspection are worth the extra attention.

Is moss on my roof actually a problem, or just cosmetic?

Light surface moss is mostly cosmetic in its early stages, but left alone it holds moisture against the roofing material, can lift shingle or shake edges over time, and tends to concentrate on the shaded, north-facing slopes that are common on wooded Guemes lots — so it's worth removing before it becomes established rather than treating it as purely cosmetic.

What does the Washington State Energy Code have to do with an exterior inspection?

The energy code sets standards for insulation, air sealing, and window performance that your home was built or upgraded to meet, and exterior problems like failed window seals, gaps in trim caulking, or moisture-damaged siding can quietly undermine that performance over time — an inspection is a chance to catch that drift before it shows up as higher energy bills or comfort complaints.

Ready to Schedule an Inspection?

If this checklist turned up items you're unsure about, or you'd simply rather have an experienced set of eyes look at your roof, windows, siding, gutters, or deck before the next wet season arrives, Alpine Exteriors (WA contractor license ALPINI751OW) serves Guemes Island along with the rest of Skagit, Island, and Whatcom counties. Reach out to schedule a walk-through and get a clear, honest read on what needs attention now versus what can wait.