Roofing & Shingles

Homeowner Summary

Your roof is the single most important protective element of your home. It shields the structure, insulation, and everything inside from rain, snow, wind, and sun. A failing roof doesn't just leak -- it can lead to mold, structural rot, ruined insulation, and tens of thousands of dollars in secondary damage. Understanding your roofing material, its expected lifespan, and what to watch for is one of the highest-value pieces of knowledge a homeowner can have.

Roofing materials vary widely in cost, durability, and appearance. Asphalt shingles cover roughly 80% of American homes due to their affordability and ease of installation. Metal, tile, and slate roofs cost more upfront but can last two to four times longer. The right choice depends on your climate, budget, local building codes, and how long you plan to stay in the home.

Most homeowners never think about their roof until something goes wrong. Annual inspections -- either from the ground with binoculars or via a professional -- catch small problems before they become catastrophic. A $300 flashing repair today prevents a $15,000 rip-and-replace tomorrow.

How It Works

A residential roof is a layered system, not just the visible shingles. From bottom to top on a typical sloped roof:

1. Roof deck (sheathing) -- Plywood or OSB panels nailed to the rafters. This is the structural foundation.
2. Underlayment -- A water-resistant barrier (felt paper or synthetic) laid over the deck. In cold climates, ice-and-water shield is applied along eaves and valleys.
3. Drip edge -- Metal flashing along eaves and rakes that directs water into the gutter.
4. Flashing -- Sheet metal installed at every penetration (chimneys, vents, skylights) and transition (valleys, dormers, walls). Flashing failures are the number-one cause of roof leaks.
5. Shingles or roofing material -- The outermost weathering layer.
6. Ridge cap and ventilation -- Specialized shingles or vents along the peak that allow attic airflow.

Water flows downhill by gravity. Every layer overlaps the one below it so water is always directed outward and downward. When any layer fails -- a lifted shingle, cracked flashing, or degraded underlayment -- water finds a path inward.

Maintenance Guide

DIY (Homeowner)

• Twice yearly (spring and fall): Visually inspect from the ground using binoculars. Look for missing, curling, or buckled shingles.
• After major storms: Check for debris impacts, lifted shingles, or dented metal panels.
• Keep roof clear: Remove branches and accumulated leaves, especially in valleys.
• Check attic interior: Look for daylight coming through the roof deck, water stains on rafters, or damp insulation.
• Maintain gutters: Clogged gutters back water up under shingles. Clean gutters at least twice per year.
• Trim overhanging branches: Keep tree limbs at least 10 feet (3 m) from the roof surface.
• Never pressure wash shingles. It strips granules and voids warranties.

Professional

• Annual inspection: A roofing professional should walk the roof, check all flashing, inspect sealant at penetrations, and evaluate shingle condition.
• After 15 years (asphalt): Increase inspections to twice per year. Look for granule loss in gutters and exposed fiberglass mat.
• Flashing reseal: Inspect and reseal all flashing every 5-7 years or whenever sealant shows cracking.
• Moss/algae treatment: In humid climates, professional treatment every 2-3 years prevents moisture retention and premature shingle decay.

Warning Signs

• Granules in gutters: Asphalt shingles shedding granules indicates aging or storm damage.
• Curling or buckling shingles: Moisture from below or manufacturing defects.
• Missing shingles: Immediate leak risk; exposed underlayment degrades rapidly under UV.
• Daylight visible in attic: Obvious deck breach.
• Water stains on ceilings or walls: Active leak; may appear far from the actual roof penetration point.
• Sagging roof deck: Structural concern. May indicate prolonged moisture damage or inadequate framing.
• Flashing pulling away from walls or chimney: Sealant failure or thermal movement.
• Ice dams forming at eaves: Indicates heat loss from the attic melting snow, which refreezes at the cold overhang.
• Interior mold or musty smell in attic: Chronic moisture intrusion.
• Increased energy bills: Poor roof/attic system allows conditioned air to escape.

When to Replace vs Repair

Repair when:

• Damage is isolated (a few missing or damaged shingles).
• Roof is less than 15 years old (asphalt) or less than half its expected lifespan.
• Flashing can be resealed or replaced at individual penetrations.
• Repair cost is less than 30% of full replacement.

Replace when:

• Roof is approaching or beyond its expected lifespan.
• Widespread granule loss, curling, or cracking across multiple sections.
• Repair costs exceed 50% of replacement cost.
• Deck sheathing requires replacement in multiple areas (indicates systemic moisture damage).
• You are re-roofing for the second time over existing shingles (most codes allow a maximum of two layers).
• After major hail or wind event where insurance covers replacement.

50% Rule: If the repair estimate exceeds 50% of the cost of a full replacement, replace the entire roof. You get a new warranty, uniform appearance, and reset the lifespan clock.

Pro Detail

Specifications & Sizing

Asphalt Shingles

| Type | Weight (per square) | Wind Rating | Lifespan | Warranty | |------|---------------------|-------------|----------|----------| | 3-Tab | 200-240 lbs (91-109 kg) | 60-70 mph | 15-20 years | 20-25 year | | Architectural (dimensional) | 240-400 lbs (109-181 kg) | 110-130 mph | 25-30 years | 30-lifetime | | Premium/luxury | 350-480 lbs (159-218 kg) | 110-130 mph | 30-50 years | Lifetime |

• UL 2218 Impact Resistance: Class 1 (lowest) through Class 4 (highest). Class 4 resists a 2-inch steel ball dropped from 20 feet.
• ASTM D3462: Standard specification for asphalt shingles made from fiberglass mat.
• ASTM D7158: Wind resistance classification (Class D: 90 mph, Class G: 120 mph, Class H: 150 mph).

Metal Roofing

| Type | Gauge | Wind Rating | Lifespan | Cost/sq ft | |------|-------|-------------|----------|------------| | Standing seam (steel) | 24-26 ga | 140-180 mph | 40-70 years | $8-$14 | | Standing seam (aluminum) | 0.032-0.040 in | 140-180 mph | 40-60 years | $10-$18 | | Metal shingles (steel) | 26 ga | 110-120 mph | 30-50 years | $7-$12 | | Copper | 16-20 oz | 110+ mph | 60-100+ years | $25-$40 |

• Galvalume (55% Al-Zn) coating standard on steel panels. Kynar 500/Hylar 5000 PVDF paint finish preferred.
• Minimum roof slope for standing seam: 3:12 (some systems rated to 1/2:12 with sealant).
• Thermal movement: steel expands approximately 0.0065 in/ft per 100 degrees F. Clip-fastened systems accommodate this; face-fastened systems are prone to loosening.

Tile Roofing

| Type | Weight (per square) | Wind Rating | Lifespan | |------|---------------------|-------------|----------| | Concrete tile | 900-1,100 lbs (408-499 kg) | 125-150 mph | 40-50 years | | Clay tile | 800-1,000 lbs (363-454 kg) | 125-150 mph | 75-100+ years |

• Requires structural evaluation: dead load of 9-11 lbs/sq ft vs 2-4 lbs/sq ft for asphalt.
• Underlayment is the true waterproofing layer under tile. Tiles shed bulk water; underlayment handles the rest.

Slate Roofing

• Weight: 700-4,000 lbs per square depending on thickness.
• Lifespan: 75-200 years (hard slate like Vermont or Welsh).
• Soft slate (Virginia, Pennsylvania black): 50-75 years.
• Fastened with copper or stainless steel nails only. Galvanized nails corrode and cause slate to slip.

Common Failure Modes

1. Flashing failure (40% of all roof leaks): Sealant dries out, metal corrodes, or step flashing is improperly integrated with siding.
2. Wind uplift: Shingles peel starting at edges and ridges. Improper nailing (high nails) drastically reduces wind resistance.
3. Ice dams: Heat loss melts snow on the upper roof; meltwater refreezes at the colder eave overhang, creating a dam that forces water under shingles.
4. Thermal cycling (metal): Repeated expansion/contraction loosens face-fastened screws. Standing seam with floating clips is the solution.
5. Biological growth: Moss and lichen retain moisture against shingles, accelerating deterioration. Zinc or copper ridge strips inhibit growth.
6. Ponding (low-slope): Water pools on flat or near-flat sections, degrading any roofing material over time.
7. Nail pops: Improperly seated nails back out over time, creating leak points.

Diagnostic Procedures

1. Interior inspection: Start in the attic. Look for daylight, staining, wet insulation, or mold on sheathing.
2. Exterior walk: Systematically inspect each roof plane. Check shingles for granule loss, cracking, lifting. Probe flashing sealant with a screwdriver.
3. Flashing check: Pay special attention to chimney, plumbing boots, skylights, and wall transitions. These are the top failure points.
4. Valley inspection: Valleys concentrate water flow. Look for wear, exposed underlayment, or debris accumulation.
5. Nail pattern verification: Lift shingle tabs to verify 4-nail or 6-nail pattern per manufacturer specs. High nails (above the nailing strip) reduce wind resistance by up to 60%.
6. Moisture scan (infrared): IR camera identifies wet insulation or sheathing beneath the roof surface without destructive testing.
7. Core sample (built-up/modified bitumen): Cut a small sample to evaluate layer adhesion and moisture content.

Code & Compliance

• IRC Section R905: Governs roof covering requirements including material standards, slope minimums, flashing, and underlayment.
• IRC R905.2.7: Asphalt shingles require a minimum slope of 2:12 (with double underlayment below 4:12).
• IRC R905.2.8.1: Ice barrier (ice-and-water shield) required in areas where average January temperature is 25 degrees F (-4 degrees C) or less. Must extend at least 24 inches (610 mm) beyond the interior wall line.
• IBC 1507.2: Commercial asphalt shingle requirements parallel IRC for applicable buildings.
• Wind zone requirements: ASCE 7 wind maps determine minimum shingle classification. High-wind zones (coastal, tornado alley) may require Class H (150 mph).
• Re-roofing: Most jurisdictions allow a maximum of two layers of asphalt shingles. Adding a third requires full tear-off.
• Permit requirements: A roofing permit is required in most jurisdictions for full replacement. Repairs below a certain square footage threshold (typically 100 sq ft) may be exempt.
• Cool roof codes: California Title 24 and some other states require minimum solar reflectance for steep-slope roofing in climate zones with high cooling loads.

Cost Guide

| Service | Typical Cost | Factors | |---------|-------------|---------| | Full asphalt replacement (avg home, 2,000 sq ft roof) | $8,000 - $15,000 | Layers to remove, deck repair, complexity, region | | Metal roof (standing seam) | $15,000 - $30,000 | Material (steel vs aluminum vs copper), complexity | | Tile roof | $20,000 - $45,000 | Structural reinforcement, material type | | Slate roof | $25,000 - $75,000 | Slate source, structural work, skilled labor scarcity | | Minor repair (few shingles) | $150 - $400 | Accessibility, matching materials | | Flashing repair | $200 - $600 | Location (chimney vs plumbing boot) | | Full flashing replacement | $500 - $1,500 | Number of penetrations | | Ice dam removal | $400 - $800 | Severity, accessibility | | Annual professional inspection | $150 - $400 | Roof size and complexity | | Roof coating (flat/low-slope) | $2,000 - $5,000 | Roof size, coating type, condition |

Regional variation is significant. Labor rates in major metros (Northeast, West Coast) can be 30-50% higher than national averages. Material costs fluctuate with oil prices (asphalt) and metals markets.

Energy Impact

The roof system directly affects heating and cooling costs. Key factors:

• Solar reflectance (cool roofs): Light-colored or reflective roofing can reduce cooling costs by 10-25% in hot climates. ENERGY STAR-rated shingles have a solar reflectance index (SRI) of 25 or higher.
• Thermal emittance: How effectively the roof radiates absorbed heat. Higher emittance = less heat transfer to the attic.
• Attic insulation and ventilation interaction: Even the best roof material cannot compensate for poor insulation or ventilation. The roof, insulation, and ventilation work as a system.
• Metal roofing advantage: Metal reflects solar radiation and re-emits absorbed heat quickly. With a radiant barrier or above-sheathing ventilation, metal roofs can reduce cooling costs by 20-40%.
• Color impact: Dark roofing materials can reach surface temperatures of 150-170 degrees F (65-77 degrees C) on a summer day. Light-colored materials stay 50-60 degrees F cooler.
• Ice dam energy penalty: Ice dams indicate attic heat loss, which means your heating system is working harder than necessary. Fixing the insulation and ventilation that cause ice dams often pays for itself in 3-5 years of energy savings.

Shipshape Integration

• Age tracking: SAM records the roof installation date and material type. As the roof approaches the end of its expected lifespan, SAM escalates the Home Health Score impact and alerts the homeowner to plan for replacement.
• Storm damage alerts: SAM monitors local weather data (hail diameter, wind speed, storm path). When a severe weather event impacts the home's area, SAM triggers a post-storm inspection recommendation and can connect the homeowner with a qualified roofing contractor.
• Exterior photo analysis: Homeowners or dealers can upload roof photos. SAM's image analysis can identify visible issues such as missing shingles, moss growth, sagging areas, and staining patterns.
• Seasonal inspection reminders: SAM schedules biannual inspection reminders (spring after freeze/thaw season, fall before winter) based on the home's climate zone.
• Home Health Score: Roof condition is a high-weight factor in the overall Home Health Score. A roof past its expected lifespan or with known issues significantly reduces the score.
• Dealer actions: When SAM detects a roof approaching end-of-life or storm damage, it generates a service recommendation for the home's assigned dealer, including roof type, age, and any known issues.
• Maintenance history: All inspections, repairs, and replacements are logged in the home's timeline, creating a verifiable maintenance record that adds value at resale.