Asphalt Shingle Roofing Cheat Sheet
Pick your roof pitch and climate to see the exact code requirements: underlayment by slope, nails per shingle, ice barrier, drip edge and flashing, plus the material list for your roof.
Doing this on a real job? Reroof with asphalt shingles: materials, tools and steps sized to your numbers.
Get the planCount squares, bundles, starter, ridge cap, drip edge and ice and water shield for your roof with the roofing calculator.
Your roof spec
| Item | Requirement | Code |
|---|---|---|
| Slope | Shingles allowed; standard single-layer underlayment. | IRC R905.2.2 |
| Underlayment | One layer, lapped 2 in at horizontal seams and 4 in at end laps, end laps offset 6 ft | IRC R905.1.1 |
| Fasteners | 4 galvanized roofing nails per shingle, 12 gauge shank, 3/8 in head, through the deck or 3/4 in into it, in the maker's nail line. | IRC R905.2.5, R905.2.6 |
| Ice barrier | Self-adhering ice and water shield from the eave edge to at least 24 in inside the exterior wall line. | IRC R905.1.2 |
| Drip edge | At eaves and rakes, lapped 2 in, extending 1/4 in past the sheathing. Under the underlayment at eaves, over it at rakes. | IRC R905.2.8.5 |
| Flashing | Step flashing at walls, 4 in minimum each leg, one piece per course; a cricket behind chimneys wider than 30 in. | IRC R905.2.8.3, R903.2.2 |
| Reroofing | One overlay layer is allowed over a single existing layer in fair shape; tear off if there are two layers or the deck is soft. | IRC R908.3 |
Materials for 2,000 sq ft (20.0 squares, 12% waste)
- Shingles: Architectural (laminated)
- Shingle bundles: 68 bundles (3 per square, waste included)
- Starter strip: 2 bundles (184 linear ft of eaves and rakes)
- Hip and ridge cap: 2 bundles (57 linear ft)
- Roofing nails, 1-1/4 in: 57 lb (about 7,168 nails at 4 per shingle)
- Underlayment: 3 rolls (Synthetic (10 squares per roll))
- Ice and water shield: 2 rolls (3 ft up the eaves and along valleys, 200 sq ft per roll)
- Drip edge: 20 10 ft pieces
- Ridge vent: 14 4 ft pieces (Stop 1 ft short of each end)
Edge lengths are estimated from the area. For exact eaves, rakes, hips and valleys use the roofing calculator.
Save this roof plan to Blueprint: the material list, every step in install order, the permit and inspection reminders and a photo log for the underlayment inspection, on your phone on the roof or at the store.
Reroof 2,000 sq ft (20.0 squares) at 6/12
Tear off and reshingle 2,000 sq ft of 6/12 roof with architectural shingles. That is 68 bundles with 12% waste, plus underlayment, ice and water shield, drip edge, starter and ridge cap.
- Materials
- $4,204
- Time
- 2 weekends
- Level
- Advanced
- 1
Permit, weather and safety setup
Most towns require a permit for a reroof, so pull it first. Pick a 3-day dry window. Install a roof anchor at the ridge before anyone works above the eave, and set roof jacks on anything you cannot walk comfortably.
- Pull the permit and order a dumpster
- Anchor installed and harness on
- Ladder tied off 3 ft above the eave
- 2
Tear off and inspect the deck
Strip shingles and underlayment to bare decking one section at a time, never more than you can dry in that day. Replace soft or delaminated sheathing and pull or set every old nail.
- Tear off one section at a time
- Replace soft decking with matching thickness
- Pull or hammer flat old nails
- 3
Drip edge and ice and water shield
Nail drip edge at the eaves first. Roll ice and water shield along the eaves to 24" inside the warm wall and down every valley. Then underlayment, then drip edge on the rakes over it.
- Eave drip edge first
- Ice and water at eaves and valleys
- Rake drip edge goes over underlayment
- Pitch
- 6/12
- Bundles
- 68
- Nails
- 4 per shingle
- Est. cost
- $4,204
10 steps · 10 tools · 8 materials
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3/5Reroof 2,000 sq ft (20.0 squares) at 6/12
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Flashing sequence
- Eaves: drip edge first, then ice and water shield over it (water runs over the metal).
- Underlayment: from the eave up, shingle-fashion.
- Rakes: drip edge over the underlayment, so wind-driven rain cannot get behind it (IRC R905.2.8.5).
- Walls: step flashing, 4 in minimum each leg, one new piece per course, nailed to the deck only.
- Counterflashing: over the step flashing, let into the mortar joint or behind the siding and housewrap.
- Chimneys: a cricket on the uphill side of any chimney wider than 30 in (IRC R903.2.2).
- Pipes: new boots; the upper flange goes under the shingles above, the lower flange over the shingles below.
Never reuse rusted or bent step flashing, and never rely on caulk or roof cement where a piece of metal should be.
Shingle Types & Warranty Grades
Understanding Shingle Quality
Asphalt shingles are rated by warranty length, weight, and wind resistance. Higher-grade shingles last longer, resist wind better, and often have better aesthetics. The warranty period directly correlates with thickness and durability.
3-Tab Shingles
Basic, economical option
- • Warranty: 20-25 years
- • Weight: 200-250 lbs per square
- • Wind rating: 60-70 mph
- • Appearance: Flat, uniform pattern
- • Cost: $80-120 per square
- • Best for: Budget projects, rentals
Architectural/Dimensional
Most popular choice
- • Warranty: 30-50 years (limited lifetime)
- • Weight: 300-380 lbs per square
- • Wind rating: 110-130 mph
- • Appearance: Dimensional, wood-shake look
- • Cost: $120-200 per square
- • Best for: Residential, best value
Premium/Luxury
Highest quality
- • Warranty: Lifetime limited warranty
- • Weight: 400-480 lbs per square
- • Wind rating: 130+ mph
- • Appearance: Ultra-dimensional, designer
- • Cost: $200-400+ per square
- • Best for: High-end homes, curb appeal
Special Features to Consider
- Algae resistant: Copper or zinc granules prevent black streaks (add $5-15 per square)
- Impact resistant (Class 4): UL 2218 rated, insurance discounts in hail areas
- Cool roof rated: Reflective granules reduce heat, energy savings in hot climates
- Enhanced wind resistance: SBS modified asphalt, higher nail strip adhesive
- Warranty transferability: Some limited lifetime warranties transfer to new homeowner
Underlayment Selection
15 lb Felt (Tar Paper)
Traditional option
- • Type: Asphalt-saturated organic felt
- • Cost: $15-25 per roll (400 sq ft)
- • Installation: Staple or nail down, 2" overlap
- • Pros: Inexpensive, breathable
- • Cons: Tears easily, limited water resistance
- • Best for: Budget reroof, low-slope areas
30 lb Felt
Heavier duty felt
- • Type: Thicker asphalt-saturated felt
- • Cost: $25-40 per roll (200 sq ft)
- • Installation: Staple or nail, 2" overlap
- • Pros: More durable than 15 lb, better water resistance
- • Cons: Heavier, still tears, wrinkles
- • Best for: Steep slopes, temporary weather protection
Synthetic Underlayment
Modern standard
- • Type: Woven or spun polypropylene
- • Cost: $50-90 per roll (1000 sq ft)
- • Installation: Plastic cap nails or staples, 4" overlap
- • Pros: Tear-resistant, slip-resistant, UV stable
- • Cons: Higher cost than felt
- • Best for: New construction, quality projects
Ice & Water Shield
Self-adhering membrane
- • Type: Rubberized asphalt, peel-and-stick
- • Cost: $60-100 per roll (200 sq ft)
- • Installation: Self-adhering, 6" overlap
- • Pros: Waterproof seal, self-heals around nails
- • Cons: Expensive, can trap moisture if overused
- • Required: Eaves, valleys, penetrations, low-slope
High-Temp Ice & Water
For metal and dark roofs
- • Type: Higher temp tolerance membrane
- • Cost: $80-120 per roll (200 sq ft)
- • Installation: Peel-and-stick, 6" overlap
- • Pros: Won't bubble in extreme heat
- • Cons: More expensive
- • Best for: Metal roofs, dark shingles, southern climates
Breathable Synthetic
Vapor-permeable option
- • Type: Micro-perforated polypropylene
- • Cost: $60-100 per roll (1000 sq ft)
- • Installation: Plastic cap nails, 4" overlap
- • Pros: Allows moisture to escape from attic
- • Cons: Higher cost
- • Best for: Cathedral ceilings, no attic ventilation
Underlayment Installation Requirements
- Eaves (ice dam protection): Ice & water shield from eaves to 24" inside warm wall (entire eave overhang + 24")
- Valleys: 18" wide centered on valley, or full ice & water shield
- Penetrations: Ice & water shield around chimneys, skylights, vent pipes
- Field: Synthetic or felt underlayment over entire roof deck
- Overlap: Horizontal laps 2-4", vertical laps 6", stagger end laps
- Fastening: Just enough to hold until shingles installed (don't over-fasten)
Nailing Patterns & Requirements
Critical Nailing Rules
Proper nailing is essential for shingle performance and warranty validity. Improperly nailed shingles will blow off in wind, void the warranty, and cause leaks. Always follow manufacturer specifications exactly.
Standard Nailing Specifications
| Shingle Type | Nails Per Shingle | High Wind Areas | Nail Location |
|---|---|---|---|
| 3-Tab Shingles | 4 nails | 6 nails | 5/8" above cutouts, 1" from ends |
| Architectural/Dimensional | 4 nails minimum | 6 nails | Through nailing strip, 1" from ends |
| Premium/Luxury | 4-6 nails (per specs) | 6 nails minimum | Check manufacturer specs |
| Starter Strip | 3-4 nails per shingle | Every 12" minimum | 3-4" from eave edge, above seal strip |
| Ridge Cap | 2 nails per cap | 2 nails (both sides) | 1" from each edge, 5 1/2" exposure |
Proper Nailing Technique
- Nail type: Roofing nails, 1-1/4" minimum (1-1/2" for thick decking)
- Nail head: 3/8" to 7/16" diameter minimum
- Material: Galvanized steel or aluminum (rust-resistant)
- Depth: Flush with shingle surface (not overdriven)
- Angle: Perpendicular to roof deck (90°), not angled
- Spacing: Follow manufacturer's nailing line precisely
Common Nailing Mistakes
- High nailing (above nail line) - shingles blow off
- Overdriven nails (cut through shingle) - creates holes
- Underdriven nails (nail head above surface) - tears shingles
- Angle nailing (not perpendicular) - poor holding power
- Missing deck entirely - no hold, will fail
- Too few nails - voids warranty, wind damage
Wind Zone Requirements
- Normal wind (under 110 mph): 4 nails per shingle standard pattern
- High wind (110-150 mph): 6 nails per shingle, hand-seal tabs with roofing cement
- Hurricane zones: 6 nails minimum, use high-wind shingles with enhanced sealant
- Coastal areas: Stainless steel nails recommended (salt air corrosion)
- Steep slopes (over 60°): 6 nails plus hand-sealing with cement
Starter Strips & Ridge Cap Installation
Starter Strip Installation
Starter strips provide a solid base for the first course and seal the eave edge to prevent wind-driven rain and uplift.
- Purpose: Fills gaps between shingle tabs at eave
- Options: Dedicated starter, or field shingles cut/reversed
- Overhang: 1/4" to 3/4" beyond drip edge (check code)
- Adhesive: Must have sealant strip facing up toward eave
- Nailing: 3-4" from eave edge, above sealant strip
- Rakes: Install starter along rake edges too
Ridge Cap Installation
Ridge caps seal the peak and hip ridges, provide finished appearance, and ensure wind and water protection at the most vulnerable areas.
- Options: Pre-cut ridge cap or field shingles cut into thirds
- Exposure: 5" to 5-1/2" exposure typical
- Direction: Install toward leeward side (away from prevailing wind)
- Nailing: 2 nails per cap, 1" from each edge, 5-1/2" back from leading edge
- Hips: Start at eave, work up to ridge
- Final piece: Seal last ridge cap nails with roofing cement
DIY Starter Strip Method
If dedicated starter strips aren't available, you can create them from field shingles:
- 1. Take full 3-tab shingle and cut off the tabs (keep the top portion with sealant strip)
- 2. For architectural shingles, reverse the shingle so tabs point up toward roof
- 3. Install with sealant strip toward roof, overhanging drip edge 1/4"-3/4"
- 4. Nail 3-4" above eave edge, spacing nails every 12"
- 5. Ensure joints in starter course don't align with joints in first course of shingles
Valley Installation Methods
Valley Importance
Valleys channel the most water on a roof (water from two slopes converges). Proper valley installation is critical to prevent leaks. Always use ice & water shield in valleys regardless of climate.
Open Valley (Metal)
Most durable method
- Material: 24" wide galvanized or aluminum valley flashing
- Base: Ice & water shield 18" wide centered on valley
- Flashing: Crimp center to form V-channel
- Shingles: Cut back 2-3" from centerline on each side
- Clip corners: Angle cut top corner to direct water
- Pros: Longest lasting, easy to clean, fast water shed
- Cons: Visible metal (aesthetics), higher cost
Closed Cut Valley
Most popular method
- Base: Ice & water shield full width of valley
- First plane: Run shingles across valley, extend 12" past centerline
- Second plane: Run shingles to valley, snap chalk line 2" off center
- Cut line: Cut second plane shingles along chalk line
- Clip corners: Angle top corner 45° to shed water
- Pros: Clean look, no exposed metal, good performance
- Cons: More labor, shingle waste
Woven Valley
Traditional method
- Base: Ice & water shield 18-24" wide
- Method: Weave shingles from alternating planes
- Pattern: Each course crosses valley, alternates overlap
- Nailing: No nails within 6" of valley center
- Best for: Similar-pitch roofs, 3-tab shingles
- Pros: Maximum coverage, no exposed membrane
- Cons: Most labor-intensive, debris can catch
Valley Installation Rules
- • Always install ice & water shield in valleys before any other underlayment
- • Extend ice & water shield at least 18" each side of valley centerline (36" total width minimum)
- • Never nail through valley within 6" of centerline (nails create leak points)
- • For closed/woven valleys, use two layers of ice & water shield in snow regions
- • Clip corners at 45° angle to prevent water from wicking under shingles
- • Open metal valleys must have crimped center to prevent water from crossing
Roof Ventilation Requirements
Why Ventilation Matters
Proper attic ventilation extends shingle life by 20-30% by preventing heat buildup (which accelerates aging) and moisture accumulation (which causes rot and ice dams). Most shingle warranties require adequate ventilation.
Code Requirement: 1 square foot of net free ventilation per 150 sq ft of attic space (1:150 ratio), split 50/50 between intake (soffit) and exhaust (ridge/roof).
Ridge Vent
Most effective exhaust
- • Type: Continuous vent along entire ridge
- • NFA: 18 sq in per linear foot typical
- • Coverage: Cut 2-3" slot both sides of ridge
- • Pros: Even exhaust, invisible, weather-resistant
- • Cons: Requires soffit intake to work
- • Cost: $3-6 per linear foot
Soffit Vents (Intake)
Essential for system
- • Type: Continuous soffit strip or individual vents
- • Coverage: 50% of total NFA requirement
- • Installation: Must have clear path to attic space
- • Baffles: Install rafter baffles to keep insulation clear
- • Pros: Creates airflow with ridge vent
- • Cost: $1.50-3 per linear foot
Box/Turtle Vents
Static roof vents
- • Type: Individual vents placed on roof
- • NFA: 50-60 sq in per vent typical
- • Spacing: 1 vent per 150 sq ft attic space
- • Location: Upper third of roof, both slopes
- • Pros: Inexpensive, works without ridge vent
- • Cost: $8-25 per vent
Gable Vents
End wall ventilation
- • Type: Louvered vent in gable end wall
- • Size: Based on attic size calculation
- • Location: High on gable end walls
- • Note: Don't mix with ridge vents (short circuits)
- • Pros: Good for gable roofs without ridge
- • Cost: $15-60 per vent
Turbine Vents
Wind-powered exhaust
- • Type: Wind-spinning turbine on roof
- • NFA: Equivalent to 2-3 static vents when spinning
- • Size: 12" or 14" diameter common
- • Pros: Active ventilation when wind blows
- • Cons: Can be noisy, visible, requires maintenance
- • Cost: $25-75 per turbine
Power Attic Vent
Electric or solar fan
- • Type: Thermostat-controlled fan
- • CFM: Size based on attic volume
- • Power: Hardwired or solar panel
- • Pros: Forced ventilation, very effective
- • Cons: Operating cost, can pull conditioned air
- • Cost: $150-500 installed
Ventilation System Design
- Best system: Ridge vent (exhaust) + continuous soffit vents (intake) for balanced airflow
- Calculate NFA: Attic sq ft ÷ 150 = total NFA required in square feet
- Split 50/50: Half NFA at soffit (intake), half at ridge/roof (exhaust)
- Don't mix types: Using ridge + gable vents creates short-circuit (air takes easy path)
- Rafter baffles: Install foam/cardboard baffles to keep soffit vent path clear of insulation
- Seal attic penetrations: Light fixtures, fans, plumbing stacks to prevent air leakage
Ventilation math
Net free area: 1,440 sq in, split 720 sq in intake at the soffits and 720 sq in exhaust, about 40 ft of ridge vent at 18 sq in per foot (IRC R806.2).
More on vents, baffles and the hatch in the attic ventilation calculator; insulation levels in the insulation R-value guide; and the water that leaves the roof in the gutter installation cheat sheet.
Step-by-Step Installation Process
Safety Setup & Deck Inspection
- •Install roof brackets or scaffolding for safe working platform
- •Set up ladder safely with stabilizer, secure at top
- •Wear fall protection harness if working on steep slopes (6:12 and up)
- •Inspect roof deck for damage, replace any rotten or broken sheathing
- •Ensure deck is properly fastened with no loose or missing panels
- •Verify deck is flat within 1/8" in 6 feet (sand high spots, shim low areas)
Install Drip Edge & Ice/Water Shield
- •Install drip edge along all eaves, nail every 12" with roofing nails
- •Drip edge should extend 1/4"-3/4" beyond fascia board
- •Apply ice & water shield from eave up to 24" past interior warm wall
- •In valleys, install 18-24" wide ice & water shield centered on valley
- •Around chimneys, pipes, and vents, install ice & water shield 6" beyond
- •Install drip edge along rakes (gable ends) over underlayment
Install Underlayment
- •Roll out felt or synthetic underlayment starting at eave
- •Overlap horizontal seams by 2-4", vertical seams by 6"
- •Stagger vertical seams (don't line up in straight line)
- •Fasten with plastic cap nails or staples every 12-18" and at seams
- •Cut underlayment around roof penetrations, seal with ice & water shield
- •Ensure underlayment is flat with no wrinkles or buckles
Install Valley Treatments
- •For open valleys: install 24" wide metal valley flashing with crimped center
- •For closed cut valleys: ensure full coverage with ice & water shield
- •Overlap valley metal sections by 6" minimum, upper piece over lower
- •Seal valley metal overlaps with roofing caulk
- •Install valley from bottom (eave) to top (ridge)
- •Mark chalk lines 2-3" from valley center for shingle cut lines (closed valleys)
Install Starter Strip
- •Install starter strip along all eaves and rake edges
- •Overhang drip edge by 1/4"-3/4" (check local code)
- •Place sealant strip toward roof (facing up)
- •Nail 3-4" above eave edge, above sealant strip, every 12"
- •Ensure starter strip joints don't align with first course joints
- •On rakes, run starter strip flush with rake drip edge
Install First Course & Establish Pattern
- •Start first full shingle course, align bottom with starter strip
- •For 3-tab: cut 6" off first shingle to stagger pattern
- •For architectural: use full shingle at rake edge
- •Nail each shingle per manufacturer specs (4-6 nails)
- •Keep nails on or just above nail line (never high nail)
- •Maintain 1/4"-3/4" overhang at rake edges
- •Snap horizontal chalk line for each course to ensure straight rows
Continue Field Courses
- •Follow shingle exposure marks (typically 5" for 3-tab, 5-5/8" architectural)
- •Stagger shingle joints (offset by 6" minimum for 3-tab, random for architectural)
- •Check alignment every 3-4 courses with chalk line
- •In valleys, extend closed-cut shingles 12" past centerline on first plane
- •Cut second plane shingles along chalk line, clip top corner at 45°
- •Never nail within 6" of valley centerline
- •Work both sides of valley alternately to maintain balance
Flash Roof Penetrations
- •For pipe vents: use rubber pipe boot flashing, shingle below and sides
- •Leave top of boot exposed, slide under shingles above vent
- •For chimneys: install step flashing up sides, counter-flashing in mortar joints
- •Skylights: install per manufacturer instructions with proper flashing kit
- •Nail flashing to deck only, not to vertical surfaces (allows movement)
- •Seal all flashing edges with roofing caulk for watertight seal
Install Ridge Cap
- •If using ridge vent: cut 1-1.5" slot on each side of ridge peak
- •Install ridge vent per manufacturer instructions (nail flanges to deck)
- •Cut ridge cap shingles from field shingles (cut into thirds) or use pre-cut caps
- •Start ridge cap at end opposite prevailing wind direction
- •Install with 5" to 5-1/2" exposure, bending over peak
- •Nail each cap with 2 nails, 1" from each edge, 5-1/2" from leading edge
- •Final cap: seal nails with dab of roofing cement
Final Inspection & Cleanup
- •Walk entire roof checking for lifted or improperly nailed shingles
- •Verify all flashing is properly installed and sealed
- •Check all valleys for proper cuts and no exposed nails
- •Seal any exposed nail heads with dab of roofing cement
- •Clean all debris from roof and gutters (nails, wrappers, shingle pieces)
- •Inspect ground perimeter with magnet to pick up dropped nails
- •Document installation with photos for warranty purposes
- •Provide homeowner with warranty information and maintenance tips
Best Practices & Common Mistakes
DO:
- Use proper fall protection when working on roofs (harness, roof brackets)
- Install ice & water shield at eaves (entire overhang + 24\" inside) and valleys
- Follow manufacturer nailing patterns exactly (4-6 nails per shingle)
- Install starter strip at eaves and rakes for proper seal
- Ensure adequate attic ventilation (1:150 ratio, intake and exhaust balanced)
- Check the weather forecast: install in dry, moderate temperatures (40-85°F ideal)
- Snap chalk lines frequently to maintain straight, aligned courses
- Store shingles on flat, stable surface and mix bundles for color consistency
DON'T:
- Work on roofs without proper safety equipment (leading cause of contractor deaths)
- High nail shingles (above nail line) - causes blow-offs and voids warranty
- Overdrive or underdrive nails (flush with surface is correct)
- Install shingles in cold weather (below 40°F) - sealant won't activate
- Skip starter strips (causes wind blow-offs at eaves and rakes)
- Nail through valleys (creates leak points in critical water channel)
- Mix gable vents with ridge vents (creates ventilation short-circuit)
- Reuse old step flashing or skip the starter course to save time
- Install new shingles over multiple old layers (creates uneven surface, voids warranty)
Frequently asked questions
How many nails per shingle?
How much exposure do asphalt shingles have?
Can I install new shingles over one layer?
Felt or synthetic underlayment?
What is the minimum slope for asphalt shingles?
Do I need a permit to reroof?
Permit check
Often needs a permit
Reroofing usually needs a permit, especially a full tear-off.
Inspections: Underlayment or in-progress, then Final
Questions about this sheet
Ask about your situation. Posting needs a free account, and your question carries over so you get an answer with your project in view. Questions we hear often get answered on this sheet.
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