Roof replacement guide
Most roofs fail gradually: shingles age, granules wash away, and small leaks spread into decking and insulation. This guide explains what wears a roof out, how to read your symptoms, when a repair is enough, and what a full replacement includes beyond the shingles you see from the street.
The causes
Most foundation damage traces back to one of four sources. Identifying the cause determines which repair approach applies and whether other work, like drainage correction, needs to happen first.
Asphalt shingles dry out, shed granules, and turn brittle under years of sun and temperature swings. Three-tab shingles typically last 15 to 20 years and architectural shingles 20 to 30, so most roofs reach end of life on schedule even without a single storm.
Wind lifts and creases shingles or tears them off entirely, while hail bruises the mat and knocks granules loose. Storm damage can total a roof that looked fine the day before, which is why it is the most common trigger for insurance-funded replacements.
An attic that traps heat and moisture cooks shingles from below and condenses water on the decking. Poor ventilation can cut years off a roof's life and is a common reason a roof fails earlier than its rated lifespan.
Bad nailing, missing underlayment, sloppy flashing, and shingles installed over an old layer all shorten roof life. A roof-over saves money up front but hides the decking, traps heat, and usually has to come off entirely at the next replacement.
Urgency
Foundation problems exist on a spectrum. Most homeowners either underreact to serious movement or overreact to cosmetic cracks. Here is how to read the difference.
An aging but intact roof with no leaks, no missing shingles, and only early cosmetic wear. Get a baseline inspection, start budgeting, and revisit after each storm season.
Visible wear that has not yet caused interior damage. Not an emergency, but a pattern worth a professional inspection before the next storm season finds the weak spots for you.
Active leaks or structural symptoms. Water that has reached the interior is already damaging decking, insulation, and drywall, and the damage compounds with every rain.
Identify your problem
Pick the closest match. The goal is not to diagnose from a screen, it is to figure out what to document and confirm with an inspection before pricing or calling a roofer.
An asphalt roof nearing or past 20 years, shingles looking flat or brittle, and neighbors with same-age homes starting to replace theirs.
Age alone puts a roof at end of life for insurance and resale even without leaks. Price a full replacement so you can plan the timing instead of reacting to a failure.Shingles in the yard after wind, visible gaps or exposed underlayment, or cracked and torn shingles concentrated in one area.
Isolated damage on a younger roof is usually a repair. Widespread damage or an older roof tips toward replacement, so get the extent documented before deciding.Water stains on ceilings, drips in the attic during rain, damp insulation, or peeling paint below the roofline.
Find the source first. A flashing or penetration leak can be repaired, but leaks in the main shingle field on an aging roof usually mean the system is failing.Dents in vents or gutters, bruised or cracked shingles after hail, or wind damage across one or more roof slopes.
This is the insurance path. Document the damage with photos and dates before any repairs, and get an inspection that maps the damage slope by slope.A visible dip in the ridge or roof plane, decking that feels spongy underfoot, or sagging visible from the attic.
Sagging points to decking or structural problems beneath the shingles. The quote should separate decking replacement and framing repair from the new roof itself.Gritty granules collecting in gutters and downspouts, shingles curling at the edges or cupping in the middle, or bald spots showing dark fiberglass.
These are the classic aging signs. The roof may have a few years left, so use them to set a budget and replacement window rather than to panic.What gets fixed
Foundation repair is not one thing. The right method depends on what is causing the problem and how far it has progressed. Each approach has a different scope, cost range, and set of exclusions.
The standard replacement: all old roofing comes off down to the decking, damaged decking is replaced, and new underlayment, flashing, and shingles go on. It is the only way to inspect and fix what is under the old roof.
The default for roofs at end of life, after major storm damage, or whenever a roof already has two layers, which is the maximum most codes allow.Pricing detail in the cost guideNew shingles installed directly over the existing layer, skipping tear-off and disposal. It costs less up front but hides the decking, adds weight, can void or shorten warranties, and shortens the new roof's life.
Only an option when the existing roof is a single flat-lying layer with sound decking, and worth a hard comparison against tear-off pricing before committing.Pricing detail in the cost guideReplacing one slope or section, usually after localized storm damage on a roof that is otherwise mid-life. New shingles rarely match weathered ones exactly, and labor per square is higher on small jobs.
Makes sense when damage is confined to one area and the rest of the roof has 10 or more years of life left, or when insurance scopes only the damaged slopes.Pricing detail in the cost guideReplacing asphalt with metal, tile, or slate. Upgrades cost two to four times more than asphalt but last 40 to 70 years for metal and 50 to 100 for tile and slate, and can lower insurance premiums in hail-prone areas.
Worth pricing when you plan to stay long-term, when hail or fire resistance matters, or when the structure can carry the extra weight of tile or slate.Pricing detail in the cost guideReplacing rotted plywood or OSB decking, and occasionally repairing rafters or trusses, before the new roof goes on. Decking is priced per sheet and is the most common surprise cost discovered mid-project.
Scoped after tear-off exposes the decking. A reliable quote states the per-sheet price up front so the surprise is the count, not the rate.Pricing detail in the cost guideNext steps
Use the resource that matches where you are in the process.