It is the question every island homeowner faces eventually: patch the roof one more time, or bite the bullet and replace it? Get it wrong in either direction and you lose money — pouring cash into a roof that is beyond saving, or tearing off one that had a decade left. This guide gives you a clear framework for deciding, calibrated to the specific realities of roofing in the San Juan Islands. Start With Three Questions Before you look at a single estimate, answer these. They resolve most cases on their own. 1. How old is the roof? Age is the strongest single signal. Asphalt shingles on an island typically last 15 to 25 years, less if moss has been neglected. Standing-seam metal can run 50 years or more. If your asphalt roof is past 20 and giving you trouble, you are usually replacing. If it is 8 years old with one leak, you are almost certainly repairing. 2. How widespread is the damage? A single leak at a flashing detail is a repair. Water showing up in several places, sagging areas, or daylight through the deck point to systemic failure. Localized problems get fixed; widespread ones get replaced. 3. What condition is the deck in? If the wood decking beneath the roofing is rotted or soft — a real risk after years of moss holding moisture on shaded north slopes — patching the surface solves nothing. Deck rot almost always tips the decision toward replacement. The Decision Table Use this to place your situation. Ranges are an estimate, not a quote, and reflect island pricing including ferry logistics — crew and material staging plus off-island disposal — which add roughly 10 to 25 percent over a comparable mainland job. Situation Repair Replace Estimated Cost One isolated leak, roof under 15 yrs ✔ $450 – $3,500 Moss present, no deck damage yet ✔ (treat) $400 – $1,600 Multiple leaks, roof 20+ yrs ✔ $11,000 – $40,000+ Rotted or sagging deck ✔ $11,000 – $40,000+ Failing flashing, sound roof ✔ $450 – $3,500 Frequent repairs, rising cost ✔ Asphalt $9k–$24k / Metal $14k–$45k+ Flat section, aging membrane ✔ or ✔ $8,000 – $26,000 When Repair Is the Right Call Repair wins when the roof is fundamentally sound and the problem is contained. Classic repair situations on island homes include: A leak traced to worn flashing around a chimney, skylight, or vent. Wind damage on the west side that lifted or tore a small area — island wind runs roughly 20 percent stronger than Anacortes, so localized wind damage is common. A cracked valley or a few displaced shingles. Moss that has taken hold but not yet rotted the deck. In these cases a targeted repair, plus preventive steps like ice-and-water membrane at the fixed valley and zinc or copper ridge strips to slow moss, buys you years at a fraction of replacement cost. When Replacement Is the Right Call Replacement wins when repairs are chasing a losing battle. Signs it is time: The roof is at or past its expected lifespan. You are repairing the same roof year after year, and the costs are climbing. Leaks appear in multiple, unrelated locations. The deck is soft, sagging, or rotted. Granules are washing into the gutters in quantity, or shingles are curling across whole slopes. Think in cost-per-year, not sticker price A $2,500 repair that buys two years costs you $1,250 a year. A $28,000 standing-seam metal roof that lasts 50 years costs $560 a year — and it is the best long-term island roof, resisting salt air, wind, and moss when built right. When you find yourself repeatedly repairing an old roof, the "cheaper" repair is often the more expensive choice over time. Island-Specific Factors That Tip the Balance A few things weigh more heavily here than on the mainland: Salt air. Near saltwater, corrosion attacks cheap fasteners and coatings. If a repair means matching an aging, already-corroding system, replacement with 24-gauge marine-grade metal and PVDF (Kynar 500) coating may make more sense sooner. Ferry logistics. Mobilizing a crew and staging materials on-island carries fixed costs. If you are going to pay to get a crew out for major work anyway, doing the job once and completely often beats repeated trips. Moss and rain. With 40 inches of rain a year and heavy November downpours, a marginal roof degrades fast. Deferring replacement on a failing roof risks deck rot that raises the eventual cost. Homeowners weighing these factors and searching for guidance on https://sanjuanroofingco.com/ should get a professional inspection before deciding — the deck condition in particular is hard to judge from the ground, and it frequently settles the question. A Simple Rule of Thumb If your roof is young and the damage is localized, repair. If your roof is old and the damage is widespread — or the deck is compromised — replace. When you are genuinely on the fence, weigh cost-per-year and the island's harsh conditions, both of which tend to favor doing the job right rather than patching indefinitely. The Bottom Line There is no universal answer, but there is a reliable method: assess age, extent of damage, and deck condition; place yourself on the decision table; then think in cost-per-year rather than sticker shock. Do that honestly, factor in salt, wind, moss, and ferry logistics, and you will spend your roofing dollars where they actually protect your home. About the Author Nathan Prewitt is a Salish Sea building inspector who has evaluated hundreds of roofs on the question of repair versus replacement. He specializes in helping island homeowners read the true condition of an aging roof before they commit to a decision.
A roof estimate should be a clear map of the work, the materials, and the money. Too often it is a single number scrawled on a business card, and homeowners find out too late that "the price" quietly excluded the tear-off, the flashing, or the dumpster. Getting an accurate estimate is a skill you can learn, and it pays off directly in fewer surprises and better negotiating footing. This guide walks you through how to prepare, what to ask, and how to compare bids like a professional, with special attention to the realities of roofing in the San Juan Islands. Step 1: Know Your Roof Before You Call The more you can describe, the more precise your estimates will be. Before reaching out to anyone, gather a few basics. The approximate age of the current roof and its material. The rough square footage of your home's footprint and the slope, if you know it (steep roofs cost more to work on). Any known problem areas: leaks, sagging, missing shingles, moss. Photos of trouble spots and, if it is safe, a few from ground level of each slope. You do not need to be an expert. You just need enough detail that a roofer can tell whether they are quoting a repair, a partial job, or a full replacement. Step 2: Decide What You Are Actually Buying A repair and a replacement are different conversations. So are "overlay" (installing new shingles over old) and a full tear-off. On the islands, where roughly 40 inches of annual rain and corrosive salt air punish shortcuts, a full tear-off with fresh underlayment is almost always the sounder long-term investment. Know which scope you want quoted so every bid answers the same question. Step 3: Get At Least Three Written Estimates One estimate tells you a number. Three tell you a market. Verbal quotes are worthless for comparison. Insist on written, itemized documents. When you are comparing options for https://sanjuanroofingco.com/ , a written estimate is the single most important document you will collect, because it lets you line up bids apples to apples instead of trusting memory. Step 4: Read the Line Items A strong estimate breaks the job into parts. Here is what a complete one should address. Line Item What to Look For Red Flag If Missing Tear-off & disposal Number of layers removed, dump fees Hidden charge later Underlayment Ice-and-water at valleys and eaves Leaks at weak points Flashing New vs. reused around chimneys, valleys Reused rusted flashing Fasteners Corrosion-resistant near saltwater Early rust streaks Ventilation Ridge and intake vents Baked shingles, moisture Cleanup Magnetic nail sweep, haul-away Nails in your yard Warranty Labor years and material coverage No recourse later Permit Who pulls it Compliance problems If a bid is dramatically cheaper than the others, the difference is almost always hiding in this list, most often in the tear-off, the flashing, or the fasteners. Step 5: Ask the Island-Specific Questions Island jobs carry costs a mainland estimate never sees. Ask directly how they handle them, and expect the answers to add roughly 10 to 25 percent over a comparable Anacortes job. Materials and Coatings Near saltwater, the right specification matters. Ask whether they use 24-gauge marine-grade Kynar 500 or PVDF-coated metal and corrosion-resistant fasteners. Cheap coatings and standard nails fail fast in salt air. Logistics How do they get crew and material to your island, and where do the tear-off debris and old shingles go? Ferry scheduling, on-site material staging, and off-island disposal are real line items, not afterthoughts. Wind and Exposure If your home sits on an exposed west-facing shoreline where wind can run about 20 percent stronger than the mainland, ask how the fastening pattern and edge details account for uplift. Step 6: Understand the Ranges Prices vary with size, slope, access, and material. Use these as an estimate, not a quote, to sanity-check the bids you receive on island homes: Asphalt shingle roof: $9,000 to $24,000 Standing-seam metal roof: $14,000 to $45,000 and up Full replacement (any material): $11,000 to $40,000 and up Repair: $450 to $3,500 Moss treatment: $400 to $1,600 Flat or low-slope roof: $8,000 to $26,000 If a bid lands far below the low end, something is missing. If it lands far above the high end, ask what justifies it. Step 7: Compare Value, Not Just Price The cheapest estimate is rarely the best value. Weigh the warranty, the quality of materials, the specificity of the scope, and the roofer's track record on similar island homes. A standing-seam metal roof that lasts 50 years and up costs more upfront but often wins on cost per year of service, especially where salt and rain shorten the life of lesser systems. Watch for Estimate Warning Signs Pressure to sign immediately or pay large deposits in cash. Vague scope language like "repair roof as needed." No mention of permits, disposal, or cleanup. Reused flashing presented as new. A number with no supporting line items at all. Bringing It Together An accurate roof estimate is not luck; it is preparation. Describe your roof clearly, define your scope, collect at least three itemized written bids, and interrogate the island-specific logistics that make or break a coastal job. When every estimate answers the same detailed questions, the right choice tends to reveal itself, and you sign knowing exactly what you are paying for. About the Author Dana Fielding is a Pacific Northwest home-services writer and former estimating coordinator who spent years translating contractor bids into plain language for homeowners. She is a firm believer that a good estimate is the cheapest insurance a homeowner can buy.
If a roof has a weak point, it is almost never the wide-open field of shingles or panels. It is the transitions, the places where the roof meets a wall, a chimney, a valley, or a vent pipe. Flashing is the thin metal that seals those transitions, and on the San Juan Islands it does the hardest work on the roof. With roughly 40 inches of rain a year, wind that runs about 20 percent stronger on west-side exposures than in Anacortes, and salt air corroding anything cheap, flashing failures are the single most common source of island leaks. This guide explains what flashing is, where it goes, how it fails, and how to specify it so it lasts. What Flashing Is and Why It Matters Flashing is corrosion-resistant metal, most often formed and lapped so that water is directed away from vulnerable joints and back onto the roof surface. Shingles and panels shed water across the open field; flashing manages the seams where that shedding would otherwise leak. Get flashing right and a roof stays dry for decades. Get it wrong and even a brand-new, expensive roof will leak at the first wind-driven storm. The island climate raises the stakes. Wind pushes rain sideways and even uphill into laps that would stay dry on the mainland. Salt air attacks fasteners and coatings. Moss on shaded slopes dams water against flashing. Every one of those pressures concentrates exactly where flashing lives. The Types of Flashing and Where They Go Different transitions call for different flashing. Knowing the vocabulary helps you understand an estimate and spot a shortcut. Flashing Type Where It Is Used Primary Job Common Failure Step flashing Roof-to-wall along a slope Weaves each shingle course to the wall Reused old pieces, missing steps Counterflashing Over step flashing, into wall/chimney Caps and protects the joint Loose, pulled from mortar Valley flashing Where two slopes meet Channels heavy concentrated flow Undersized, corroded Drip edge Eaves and rakes Directs water into gutters Omitted, poorly lapped Vent/pipe boot Around penetrations Seals plumbing and vent pipes Cracked rubber collar Chimney flashing Around chimney base Seals a large, complex joint Sealant-only shortcuts Kickout flashing Bottom of a roof-wall junction Diverts water into the gutter Left off entirely The kickout flashing deserves special mention because it is the most commonly omitted piece. Without it, water running down a wall-to-roof junction pours behind the gutter and into the wall, rotting sheathing and framing invisibly for years. How Flashing Fails on the Islands Flashing rarely fails from one dramatic event. It fails from steady island exposure. Corrosion Near saltwater, cheap fasteners and thin coatings rust. A corroded fastener becomes a pinhole leak and a rust stain. This is why coastal flashing must use corrosion-resistant fasteners and durable metal, not the least expensive option in the truck. Sealant Dependence Sealant is a supplement, never the primary defense. Flashing should shed water by its shape and overlap. When an installer relies on a bead of caulk to do the flashing's job, that joint is on a countdown; sealant dries, cracks, and lets go, often within a couple of wet seasons. Reused Flashing During a re-roof, some crews leave old step or valley flashing in place to save time and money. Old metal that is corroded or improperly lapped undermines an otherwise new roof. Flashing should generally be replaced with the roof. Moss and Debris On shaded north slopes under Douglas fir, moss and needle debris dam water against flashing, forcing it under laps. Keeping valleys and wall junctions clear is part of protecting the flashing. Specifying Flashing That Lasts Here Homeowners planning https://sanjuanroofingco.com/ should hold their roof to a few island-appropriate standards. Corrosion-resistant metal and fasteners. Near saltwater, match the flashing quality to the roof; on premium metal roofs that means marine-grade materials and fasteners that will not rust. Ice-and-water membrane at valleys and eaves. This self-adhering membrane belongs beneath valleys and along eaves as a second line of defense where wind-driven rain and any winter ice back up. Proper step and counterflashing at walls. Insist on woven step flashing with counterflashing, not a smear of sealant. Kickout flashing at every wall-to-roof termination. Non-negotiable to protect the wall below. New flashing with a new roof. Do not let old flashing be reused under new roofing. Correct valley sizing. Valleys carry concentrated flow during heavy November rain and must be sized and lapped for it. Flashing and Roof Material Flashing choices interact with the roof type. Standing-seam metal, the best long-term island roof at 50-plus years, integrates metal flashing that matches the panels for a unified, corrosion-resistant system. Asphalt roofs rely on step, valley, and drip-edge flashing done correctly. Flat and low-slope roofs using TPO, PVC, EPDM, or torch-down modified bitumen depend on membrane-integrated flashing details at every edge and penetration, where most flat-roof leaks originate. What Flashing Work Costs The ranges below are an estimate, not a quote. Island jobs typically run roughly 10 to 25 percent above comparable mainland work because crews and materials arrive by ferry and old material leaves the same way. Flashing Scope Typical Range Single flashing repair (boot, small section) $450–$1,500 Chimney or valley reflashing $1,000–$3,500 Full flashing replacement during re-roof Included in roof scope Moss treatment protecting flashing $400–$1,600 The Bottom Line Flashing is small, cheap relative to the roof, and responsible for most of the leaks that damage island homes. Spend attention here. Demand corrosion-resistant materials, insist on proper step, counter, valley, and kickout details, add ice-and-water membrane at valleys and eaves, and never let old flashing survive a new roof. On the San Juan Islands, where wind and salt punish every seam, well-specified flashing is the difference between a roof that lasts its full life and one that leaks before its warranty is out. About the Author Grant Ellison is a roofing-systems writer and former sheet-metal apprentice who has documented flashing and waterproofing practices across the wet, wind-exposed Pacific Northwest coast. He writes to help homeowners recognize quality work at the roof's most vulnerable joints.
Flat Roof Systems Compared: TPO vs. EPDM vs. Torch-Down
Not every roof in the San Juan Islands is a steep, pitched slope shedding rain into the firs. Modern additions, garages, dormers, and contemporary homes often feature flat or low-slope sections — and those areas need a completely different roofing approach. Standing-seam metal and asphalt shingles rely on gravity and pitch to shed water. A flat roof has almost no pitch, so it must rely on a fully sealed, continuous membrane to hold water out. In a place that sees roughly 40 inches of rain a year, that membrane is doing serious work. Three systems dominate the low-slope world: TPO, EPDM, and torch-down modified bitumen. Each has real strengths and real drawbacks, and the right choice depends on your slope, your budget, salt exposure, and how long you plan to own the home. Let's compare them honestly. What "Flat" Really Means A truly flat roof would pond water and fail fast. What we call flat roofs actually carry a slight slope — enough to drain toward scuppers or drains. The membrane's job is to stay watertight across that entire plane, including around every penetration, edge, and seam. Because water sits longer on a low-slope roof than it ever would on a pitched one, seam quality and drainage design matter more than almost anything else. Homeowners researching https://sanjuanroofingco.com/ should understand that the membrane material is only half the equation — installation quality and proper drainage determine whether any of these systems reach their potential lifespan. The Three Contenders TPO (Thermoplastic Polyolefin) TPO is a single-ply white membrane that's become popular for its heat-welded seams and reflective surface. The welded seams are a genuine advantage: instead of relying on adhesive, the sheets are melted together into a continuous bond, which resists the water intrusion that plagues glued systems. The reflective white surface bounces sunlight, though on the islands — where cooling loads are modest and gray skies common — that reflectivity matters less than it would in a hot southern climate. TPO handles moisture well and holds up reasonably against the elements. Its main caveat is that quality varies by manufacturer and thickness, so specifying a robust membrane matters. EPDM (Ethylene Propylene Diene Monomer) EPDM is a synthetic rubber membrane, usually black, known for durability and flexibility. It's been used for decades and has a long track record. Its flexibility is a real asset in a climate with temperature swings, and it resists many forms of weathering well. The traditional weak point is the seams, which are often adhesive-bonded rather than welded — though modern tapes and detailing have improved this considerably. EPDM's black surface absorbs heat, which in a cold, wet climate can actually help dry the roof and shed light snow. Near saltwater, EPDM's chemistry holds up well, but as with any system, the fasteners and edge metal must be corrosion-resistant. Torch-Down (Modified Bitumen) Torch-down, or modified bitumen, is a multi-layer asphalt-based system applied with heat — the installer literally torches the rolls to melt and adhere them. It creates a thick, tough, redundant membrane that many island homeowners trust for its ruggedness underfoot and its proven waterproofing. The multiple layers provide backup: if one layer is nicked, others still protect. The trade-offs are installation risk (open flame requires an experienced, careful crew) and a heavier, less reflective surface. On a wet island, the ruggedness often outweighs the drawbacks, especially on roofs that see foot traffic. Head-to-Head Comparison Feature TPO EPDM Torch-Down Membrane type Single-ply thermoplastic Single-ply rubber Multi-layer asphalt Seam method Heat-welded (strong) Adhesive/tape Heat-fused Typical color White (reflective) Black (absorptive) Dark, granulated Flexibility Good Excellent Moderate Foot-traffic durability Moderate Moderate Excellent Salt-air tolerance Good Good Good Installation risk Low Low Higher (open flame) Typical lifespan 15–25 years 20–30 years 15–25 years Cost Expectations Flat roofing on the islands carries the same ferry-logistics premium as any other project — roughly 10 to 25 percent over comparable mainland work, once you factor in crew crossings, material staging, and off-island disposal. For planning purposes, a flat roof project typically falls in the range of $8,000 to $26,000. Treat that as an estimate, not a quote; the final number depends on square footage, insulation, tear-off, drainage work, and the number of penetrations. Project Type Typical Range Flat roof (any system) $8,000 – $26,000 Flat roof repair $450 – $3,500 Cheaper isn't better here. A poorly installed low-slope roof leaks, and a leak on a flat roof spreads horizontally before it ever shows inside — meaning damage is often extensive by the time you notice. Which System Fits Island Conditions? There's no universal winner. The right pick depends on your specifics: Choose TPO if you want welded seams and a reflective surface, and you're specifying a quality-grade membrane. Choose EPDM if flexibility and a long, proven track record matter most, and your roof sees minimal foot traffic. Choose torch-down if durability underfoot and layered redundancy are priorities, and you're hiring a crew experienced with the open-flame application. Whatever you select, the fundamentals stay constant: positive drainage so water doesn't pond, corrosion-resistant edge metal and fasteners for our salt air, careful flashing at every penetration, and an installer who has done low-slope work on the islands before. The membrane is only as good as the hands that install it and the drainage designed beneath it. The Bottom Line Flat roofs demand respect in a wet climate. Get the drainage, the seams, and the flashing right, and any of these three systems will serve you well for two decades or more. Get them wrong, and no membrane on earth will save you. Compare the materials, but scrutinize the installer just as hard — on a low-slope island roof, workmanship is the difference between a dry home and a slow, invisible leak. About the Author Terrence Boyle is a commercial and residential roofing writer with a background in building envelope consulting across the Pacific Northwest. He specializes in low-slope and flat-roof systems and enjoys demystifying membrane choices for homeowners.