Home Exterior Inspection Checklist for Arlington, Washington

Updated August 2026 · Alpine Exteriors · WA contractor license ALPINI751OW

Why This Checklist Matters in Arlington and the Stillaguamish Valley

Arlington sits where the flat farmland of the Stillaguamish Valley starts climbing toward the Cascade foothills near Darrington and Oso, and that location gives local homes a mix of weather challenges that a generic maintenance checklist won't cover. Winters here bring long stretches of steady, soaking rain from October through March, punctuated by the occasional atmospheric river event that can drop several inches of rain over a few days. That kind of sustained wet weather doesn't just test your roof and siding once a year during a big storm — it tests every seam, flashing detail, and gutter joint for months at a time, and it rarely gives wet building materials a real chance to dry out between rounds.

Because so many Arlington properties sit under mature fir, cedar, and maple trees, north- and east-facing roof slopes stay shaded for most of the day, which lets moss and moisture-loving algae take hold far faster than on a roof with open sun exposure. Moss looks cosmetic, but it holds water directly against the shingle mat and can work its way under tabs and shingle edges over a season or two. Homes closer to the foothills also see the occasional snow or ice event that homes down in Everett or on the Sound rarely deal with — cold air draining out of the Cascade valleys can drop temperatures and bring a few inches of snow or a glaze of ice even when the lowlands stay wet and mild, and that freeze-thaw cycling is hard on anything already compromised by moisture.

Wind is part of the picture too. Fall and winter storm systems moving through Western Washington regularly bring gusty conditions through the Stillaguamish Valley, and older or already-weakened roofing, siding, and fencing tend to show damage first. Finally, most homes built or remodeled in the last couple of decades in Snohomish County were built to the Washington State Energy Code, which requires a tighter building envelope for efficiency. A tighter envelope is good for heating bills, but it also means moisture that does get in — through a failed window seal, a gap in siding, or a poorly vented bath fan — has fewer ways to escape, so catching small exterior problems early matters more here than it would in a leakier, older-style home. A homeowner who walks the exterior once or twice a year, ideally before the fall rains start and again after a significant windstorm, catches most problems while they're still a repair rather than a replacement. Alpine Exteriors put this checklist together from what we actually see on service calls around Arlington, Stanwood, and the rest of our Snohomish and Skagit county service area, not from a generic national template.

The Exterior Inspection Checklist

Roof

• Moss or algae growth on shaded or north-facing slopes — moss holds water against the shingle surface and can lift tabs, shortening the roof's usable life in our wet climate.
• Missing, cracked, or curling shingles — exposed decking underneath has no protection during the heaviest rain months.
• Lifted, rusted, or gapped flashing around chimneys, vents, and skylights — flashing is the most common leak point on an otherwise sound roof, especially after wind events.
• Heavy granule buildup in the gutters — significant granule loss usually means the shingles are past the point of reliable protection.
• Sagging sections or soft spots when viewed from a ladder or binoculars — can point to water-damaged roof decking underneath.

Gutters & Downspouts

• Gutters pulling away from the fascia or sagging between hangers — standing water adds weight, and a sagging run can fail completely during a heavy storm.
• Downspouts discharging within a few feet of the foundation — this concentrates roof runoff exactly where crawl spaces and foundations are most vulnerable to saturation.
• Needles, cones, and moss clogging the gutter troughs — conifer debris builds up fast under Arlington's tree cover and causes overflow that runs straight down the siding.
• Staining or streaking on siding below gutter joints — usually means an overflow or leak point has been active for a while.

Siding & Trim

• Cracked, warped, or soft siding panels — extended rain exposure rots wood trim and can delaminate hardboard or composite siding over time.
• Peeling or bubbling paint — often a sign that moisture is trapped behind the paint film rather than simple sun weathering.
• Failed or missing caulk at trim joints, corners, and penetrations — this is where wind-driven rain gets behind the cladding and into the wall assembly.
• Dark streaking, mildew, or moss on shaded walls — north- and west-facing walls under tree cover stay damp longest here and grow biological staining faster than sunnier walls.

Windows & Doors

• Fogging or moisture between panes of double-glazed windows — the insulated seal has failed and the gas fill has escaped, hurting both comfort and energy performance.
• Soft, discolored, or spongy wood at sills and thresholds — sills take the brunt of wind-driven rain and typically rot from the bottom edge inward.
• Frames that stick, won't latch fully, or show visible gaps — settling or swollen frames let in both drafts and water.
• Worn, compressed, or missing weatherstripping — undermines the airtightness the Washington State Energy Code assumes your home has, and lets cold, damp air in around the frame.

Decks

• Soft, spongy, or splintering wood, especially near the ledger board where the deck attaches to the house — the ledger connection is structural, and rot there is a safety issue, not just a cosmetic one.
• Rust streaking around fasteners or joist hangers — signals corrosion that weakens the hardware's holding strength over time.
• Widening gaps between deck boards — some seasonal movement is normal, but persistent, growing gaps often mean boards are drying out and cupping.
• Water pooling on the deck surface instead of draining off — indicates the original drainage slope has settled, so water is soaking in rather than shedding.

Foundation & Drainage

• Grading that slopes toward the house instead of away from it — once fall rains start, this sends water straight to the foundation instead of away from it.
• Foundation cracks wider than a pencil — can indicate settling that's worth having evaluated before it progresses.
• White, chalky mineral deposits (efflorescence) on foundation walls — evidence that moisture is actively moving through the concrete.
• Blocked crawl space vents or a damp, musty crawl space — trapped moisture under the house feeds wood rot and mold that can eventually work into the floor framing above.

Attic & Ventilation

• Visible daylight or noticeable drafts at roof vents — gaps here let in wind-driven rain and undercut the insulation's performance.
• Insulation that's damp, compressed, or matted down — wet insulation loses much of its R-value and usually signals a leak somewhere above it.
• Condensation, staining, or frost on the underside of the roof sheathing — often means a bathroom or kitchen exhaust fan is venting into the attic instead of outside, a common miss in tighter, energy-code-built homes.
• Blocked soffit or ridge vents — without steady airflow, attics trap moisture that can rot sheathing from the inside out.

What to Do If an Item Fails

Not every item on this list is an emergency, and it helps to sort what you find into three rough categories before deciding what to do next. The first category is small maintenance you can safely handle yourself: clearing debris from gutters and downspouts, touching up cracked exterior caulk on the ground floor, or resetting a loose downspout bracket. The second category is items worth photographing and monitoring, like hairline foundation cracks or minor paint peeling, where the fix isn't urgent but the item should go on a list to revisit each season so you can tell whether it's getting worse. The third category is anything that points to active water intrusion or a structural concern — a soft spot in roof decking, rot at a deck ledger, a window that's actively leaking during storms — and those deserve prompt attention rather than a wait-and-see approach, because our wet season doesn't give damaged materials time to dry out and stabilize on their own.

For anything involving roof access, be cautious about doing it yourself, especially on moss-covered or shaded slopes that stay slick well after the rain stops. A slippery roof is one of the more common ways a straightforward inspection turns into an injury. Whatever you find, take dated photos from a few angles — that record is useful both for tracking whether a problem is progressing and for supporting an insurance claim if damage turns out to be storm-related. If you do decide to power wash moss off a roof yourself, use a soft-wash approach rather than a pressure washer directly on the shingles, since high-pressure water can strip granules and shorten the roof's life faster than the moss would have.

When to Call a Professional

Some items on this checklist are reasonable for a homeowner to handle with basic tools and a free Saturday. Others aren't, and knowing the difference matters both for safety and for making sure a repair is actually done correctly rather than just patched over. Call a licensed contractor when you see structural warning signs — a sagging roofline, soft or spongy decking near a ledger board, foundation cracks that seem to be widening, or an active leak you can't trace to an obvious, accessible source. Roof, siding, and window work that requires proper flashing details or integration with the existing weather barrier is also worth having a professional handle, since a repair that looks fine on the surface but isn't flashed correctly underneath can trap water rather than shed it, turning a small fix into a bigger one down the road.

It's also worth calling in a professional simply for a second set of eyes if you're not confident interpreting what you're seeing — the difference between cosmetic weathering and an early leak isn't always obvious from the ground. Alpine Exteriors is licensed in Washington (contractor license ALPINI751OW) and inspects roofing, siding, windows, gutters, and decks across our Skagit, Island, and Snohomish county service area, including Arlington and the surrounding Stillaguamish Valley. A written scope and honest assessment of what actually needs attention now versus what can reasonably wait is worth more than a rushed sales pitch, and any contractor you hire should be willing to explain their reasoning, not just quote a price.

FAQ

How often should Arlington homeowners inspect their home's exterior?

Twice a year covers most homes well: once in early fall before the heavy rains set in, so you can clear gutters and catch anything that needs fixing before winter, and once in spring after the wet season has passed, to assess any damage from storms, wind, or the occasional freeze. If a significant windstorm or heavy snow event comes through, it's worth a quick walk-around afterward too, since storm damage isn't always obvious from inside the house.

Why does my roof grow moss when my neighbor's doesn't?

Moss growth mostly comes down to shade and moisture retention rather than shingle quality alone. Roof slopes facing north or shaded by mature trees stay damp longer after every rain, which gives moss spores time to take hold, while a neighbor's more sun-exposed roof dries out faster and resists growth better. Tree cover, roof pitch, and even which way the house faces on the lot all play a role, which is why two similar homes on the same street can age very differently.

Does homeowners insurance cover storm damage to my roof or siding in Snohomish County?

Most standard homeowners policies cover sudden, storm-related damage — a tree limb through the roof or shingles torn off in a windstorm, for example — but coverage details, deductibles, and exclusions vary by policy and insurer, so this isn't something a contractor can answer definitively for you. Gradual damage from long-term neglect, like moss that's been left to grow for years, is typically treated differently than sudden storm damage. Documenting your home's condition with dated photos before and after storms, and reviewing your specific policy with your insurance agent, is the best way to know where you stand.

Do window or siding replacements in Arlington need to meet the Washington State Energy Code?

Yes — new construction, additions, and most window and siding replacement work in Washington are subject to the Washington State Energy Code, which sets requirements for insulation values, air sealing, and window performance. The specific requirements depend on the scope of the project and whether it's treated as a repair, alteration, or full replacement, so it's worth confirming code requirements with your contractor or the local building department — in this case Snohomish County or the City of Arlington, depending on your property's jurisdiction — before work begins.

Ready to Have Your Home's Exterior Inspected?

A checklist gets you most of the way there, but some issues — a flashing detail that looks fine but isn't sealed correctly, or moisture damage hidden behind siding — are hard to fully assess without hands-on experience. Alpine Exteriors provides roofing, window, deck, and gutter inspections for homeowners throughout Arlington, Stanwood, Camano Island, and the rest of our Skagit, Island, and Whatcom county service area, and we're licensed in Washington under contractor license ALPINI751OW. If this checklist turned up something you'd like a second opinion on, or you'd simply rather have a professional walk the exterior before the fall rains arrive, reach out to Alpine Exteriors to schedule an inspection.