If you’re planning a roof replacement or new roof installation, you need more than just shingles. A proper roofing system includes structural layers, moisture barriers, flashing, ventilation, fasteners, and finishing components.
Short answer:
To roof a house, you need roof decking (if replacing), underlayment, ice and water shield (where required), flashing, drip edge, roof covering (shingles, metal, tile, or slate), ventilation components, fasteners, and sealants. Material choice depends on climate, budget, roof pitch, and local building codes.
Whether you’re a homeowner comparing quotes or a contractor verifying your checklist, this guide walks through everything required step by step.
Understanding the Layers of a Roofing System
A roof isn’t one material. It’s a layered system designed to resist water, wind, heat, and structural movement.
From bottom to top:
- Roof framing (rafters or trusses)
- Roof decking (sheathing)
- Underlayment
- Ice & water shield (where required)
- Flashing and drip edge
- Roof covering (shingles, metal, tile, etc.)
- Ventilation components
Missing one layer can lead to leaks, mold, structural damage, or code violations.
Core Materials Needed for Roofing a House
1. Roof Decking (Sheathing)
Roof decking is the structural base installed over rafters.
Common materials:
- OSB (Oriented Strand Board)
- Plywood (CDX)
OSB vs Plywood
| Feature | OSB | Plywood |
|---|---|---|
| Cost | Lower | Higher |
| Moisture Resistance | Moderate | Better |
| Strength | Strong | Slightly stronger |
| Common in USA | Yes | Yes |
Decking must be replaced if:
- It feels soft or spongy
- There’s visible rot
- It has delamination or sagging
Building codes referenced by the International Residential Code (IRC), published by the International Code Council (ICC), require structurally sound decking before roofing installation.
2. Underlayment
Underlayment is a moisture barrier between decking and roofing material.
Types of underlayment:
- Asphalt-saturated felt (15 lb or 30 lb)
- Synthetic underlayment
- Ice and water shield (self-adhering membrane)
Who needs ice and water shield?
- Homes in northern states (Minnesota, Michigan, New York)
- Roofs with low slope
- Areas prone to ice dams
The IRC requires ice barrier protection in regions where there’s a history of ice forming along eaves.
3. Drip Edge
Drip edge flashing is a metal strip installed along roof edges.
It:
- Directs water into gutters
- Protects fascia boards
- Prevents wind-driven rain intrusion
Most U.S. municipalities now require drip edge under IRC R905 standards.
4. Flashing
Flashing prevents leaks at roof penetrations and transitions.
Types of flashing:
- Step flashing (sidewalls)
- Valley flashing
- Chimney flashing
- Vent pipe boots
- Skylight flashing
Most homeowners forget flashing but improper flashing is one of the top causes of roof failure.
5. Roof Covering (Top Layer)
This is the visible material.
Asphalt Shingles
Most common residential roofing material in the U.S.
- 3-tab shingles
- Architectural shingles
- Impact-rated shingles
Brands like GAF, Owens Corning, CertainTeed, and Tamko dominate the market.
Lifespan: 15–30 years
Cost: $1–$2.50 per sq ft (materials only)
Metal Roofing
Includes:
- Standing seam metal
- Corrugated panels
- Aluminum or steel systems
Lifespan: 40–70 years
Cost: $3–$7 per sq ft (materials)
Excellent for:
- Snow-heavy regions
- Fire-prone Western states
- Long-term homeowners
Tile Roofing (Clay or Concrete)
Common in:
- Arizona
- California
- Florida
Durable and heat-resistant but heavy. May require structural reinforcement.
Slate Roofing
Natural stone material with 75–100+ year lifespan. Premium category and structurally demanding.
6. Ventilation Components
Proper ventilation prevents moisture buildup and premature shingle failure.
Common components:
- Ridge vent system
- Soffit vents
- Gable vents
- Roof turbines
The National Roofing Contractors Association (NRCA) recommends balanced intake and exhaust ventilation for longevity.
7. Fasteners & Adhesives
- Galvanized roofing nails
- Roofing screws (for metal)
- Roofing cement
- Sealant caulk
Improper fasteners can void manufacturer warranties.
Roofing Material Quantity Calculation
Roofing materials are measured in “squares.”
1 roofing square = 100 square feet.
Example: 2,000 sq ft roof
2,000 sq ft ÷ 100 = 20 squares
Add 10–15% waste factor:
20 × 1.15 = 23 squares
If using shingles:
- 3 bundles per square
- 23 squares × 3 = 69 bundles
Always round up.
Step-by-Step Roofing Material Installation Order
- Install or repair decking
- Apply underlayment
- Install ice & water shield (if required)
- Install drip edge
- Install flashing
- Install shingles or metal panels
- Add ridge caps and ventilation
OSHA requires fall protection systems for workers during installation.
Roofing Material Cost in the USA (2026 Estimates)
| Material Type | Material Cost / Sq Ft | Installed Cost / Sq Ft |
|---|---|---|
| Asphalt Shingles | $1–$2.50 | $4.50–$8 |
| Metal Roofing | $3–$7 | $8–$16 |
| Tile Roofing | $4–$10 | $10–$20 |
| Slate | $8–$20 | $15–$30 |
Costs vary regionally:
- Higher on West Coast
- Moderate in Texas
- Elevated in hurricane zones due to code requirements
Search terms like “roof replacement cost in Texas” or “Florida hurricane roofing materials” often reflect code-driven material upgrades.
Climate-Based Material Requirements in the U.S.
Hurricane Zones (Florida, Gulf Coast)
- Impact-rated shingles
- Enhanced wind uplift rating
- Secondary water barrier
- Strict permit requirements
Insurance companies may require documentation.
Northern States (Snow & Ice)
- Ice and water shield mandatory
- Strong ventilation to prevent ice dams
- Metal roofing popular for snow shedding
Western Wildfire Zones
- Class A fire-rated roofing materials
- Metal or tile preferred
Southwest Heat
- Reflective shingles
- Cool roof coatings
- Tile roofing common
Energy-efficient roofing materials may qualify for federal tax incentives.
Permit & Code Requirements
Most U.S. cities require a building permit for roof replacement.
Common requirements:
- Inspection
- Wind rating compliance
- Ice barrier installation (where required)
- Proper fastening pattern
Check with your local building department before purchasing materials.
DIY vs Hiring a Contractor
DIY May Work If:
- Single-story home
- Simple roof pitch
- Asphalt shingles
- Construction experience
Hire a Contractor If:
- Steep roof
- Structural repairs needed
- Metal, tile, or slate roofing
- Insurance claim involved
Licensed contractors typically source materials from Home Depot, Lowe’s, or roofing supply distributors.
Common Mistakes to Avoid
- Skipping underlayment
- Reusing old flashing
- Underestimating material waste
- Ignoring ventilation
- Not checking HOA restrictions
- Installing over damaged decking
Disposal & Additional Materials
Don’t forget:
- Dumpster rental
- Tear-off tools
- Replacement fascia or soffit boards (if damaged)
- Gutter adjustments
Some states require specific disposal procedures for roofing waste.
Insurance & Warranty Considerations
- Wind uplift ratings affect insurance approval
- Impact-resistant shingles may lower premiums
- Manufacturer warranties require correct installation and approved fasteners
Always keep receipts and documentation.
FAQs
1. Do you need underlayment under shingles?
Yes. Underlayment is required by code and protects against moisture intrusion beneath shingles.
2. How many bundles of shingles per square?
Most asphalt shingles require 3 bundles per roofing square (100 sq ft).
3. Do I need new decking when replacing a roof?
Only if the existing decking is damaged, rotted, or structurally compromised.
4. What materials are needed for a metal roof?
Metal panels, synthetic underlayment, closure strips, screws, flashing, ridge caps, and ventilation components.
5. What roofing material is best for hurricanes?
Impact-rated architectural shingles or standing seam metal with high wind uplift ratings.
6. Can you install shingles over old shingles?
Some codes allow one additional layer, but full tear-off is recommended for inspection and warranty compliance.
7. How much extra roofing material should I order?
Add 10–15% to account for cuts, waste, and ridge caps.
8. Is drip edge required by code?
Yes, most jurisdictions following IRC standards require drip edge installation.
Conclusion
Roofing a house requires more than shingles. A complete system includes decking, underlayment, flashing, drip edge, ventilation, fasteners, and the roof covering itself. The right materials depend on climate, budget, local code requirements, and long-term plans.
Before purchasing materials:
- Measure your roof in squares
- Add 10–15% waste
- Check local permit requirements
- Consider climate-specific upgrades
- Compare material lifespan vs cost
A properly installed roofing system protects your home for decades. Cutting corners on materials often leads to costly repairs later.
