Roof shingles are overlapping asphalt elements forming a watertight roof barrier, popular for affordability, ease, and durability. Installation involves measuring the roof, prepping the deck, laying underlayment, and nailing shingles in staggered rows. Use starter strips, flashing, and ridge caps to seal edges. Avoid misaligned seams and incorrect nailing.
What are roof shingles and why are they popular?
Roof shingles are overlapping elements made of asphalt that create a watertight barrier on sloped residential roofs. The shingles interlock and overlap to guide rainwater down to the gutters.
Asphalt shingles are the dominant material for residential roofing in the U.S., covering more than 70% of homes. They’re composed of a fiberglass mat core, asphalt coating, and ceramic granules for UV protection.
Why are asphalt shingles widely used?
- Affordability: Asphalt shingles cost between $90–$160 per roofing square (100 sq. ft.)
- Ease of installation: Lightweight and simple to cut or fasten
- Style variety: Available in many colors and textures
- Durability: Lifespan of 15 to 30 years for three-tab, up to 50 years for architectural types
Due to their compatibility with standard roof pitches, shingles are a common choice for asphalt shingle roof installation in both renovations and new builds.
What tools and materials are needed to install roof shingles?
Essential tools
- Roofing shovel
- Utility knife
- Chalk line
- Hammer or nail gun
- Tape measure
- Roofing square
- Ladder and roof harness
- Caulking gun
Required materials
- Asphalt shingles (three-tab or architectural)
- Starter strip shingles
- Roofing nails (galvanized, 1¼ to 1½ inch)
- Synthetic underlayment
- Drip edge flashing
- Ridge cap shingles
- Roof sealant and flashing
These components form a complete roofing system. Roof installation specialists recommend using only code-compliant materials for long-term performance.
How to measure your roof and calculate materials
Step 1: Measure area
Multiply each roof section’s length × width in feet. Add together for total square footage.
Example: 30 ft × 20 ft × 2 slopes = 1,200 sq. ft.
Step 2: Convert to squares
Divide total area by 100 to calculate roofing squares:
- 1,200 ÷ 100 = 12 squares
Step 3: Estimate shingles
Each square requires 3 bundles:
- 12 squares × 3 = 36 bundles
Step 4: Add 10–20% for waste
- Final order: ~40–43 bundles
Confirm calculations with a roof replacement contractor for complex designs or steep slopes.
How to prep the roof for shingle installation
1. Clear surroundings
Cover landscaping, move cars, and set up debris catchment.
2. Remove old roofing
Use a roofing shovel to strip off old shingles and nails. Sweep deck clean.
3. Inspect decking
Replace rotted or cracked plywood. Deck must be flat, dry, and solid.
4. Install underlayment
Roll synthetic underlayment from eave to ridge, overlapping each row 3–4 inches.
Apply ice-and-water shield in valleys or cold zones.
5. Apply drip edge flashing
Install at eaves and rakes, with 2-inch overlaps between pieces.
6. Lay starter strip shingles
Starter strips should extend ½ inch beyond the edge and align with drip flashing.
Before laying shingles, inspect for structural issues. If needed, book roof damage repair services to fix the deck or flashings.
How to install roof shingles step by step
Begin at the eave
Lay the first course directly over the starter strip, with a ½ inch overhang.
Nail shingles correctly
Use 4 nails per shingle, or 6 in high-wind areas. Nails must be:
- ¾ inch above the cutouts
- Driven flush, not overdriven
Stagger each row
Cut 6 inches off the first shingle of the second row. Continue stepping in 6-inch increments.
This prevents vertical seams from aligning — a cause of leaks.
Align with chalk lines
Mark horizontal guides every 5 inches. Maintain this exposure for each row.
Trim edges
Cut shingles flush to the rake using a hook blade. Cap exposed rake edges with flashing or sealant.
Finish the ridge
Use ridge cap shingles or cut three-tab shingles into thirds. Overlap each by 5–6 inches and seal the final piece with roofing cement.
For optimal finish at the top, partner with residential roof repair teams familiar with ridge detailing.
Common mistakes when installing roof shingles
Incorrect nailing
- Overdriven nails break through the shingle
- Underdriven nails don’t hold properly
- Misplaced nails miss the nail zone and void warranty
Skipping flashing or underlayment
Without them, water infiltrates valleys and penetrations.
Not staggering seams
Aligned vertical joints create leak paths.
Exposed fasteners
Unsealed nails rust and cause leaks. Cover with sealant immediately.
Improper ridge capping
Caps must face away from prevailing wind and overlap evenly.
After storms or bad installs, storm damage and restoration experts can fix vulnerable roof sections quickly.
FAQs about installing roof shingles
Can I install shingles over an old roof?
Yes, if there’s only one layer and the deck is sound. Still, most pros recommend full tear-off for best results.
How many bundles cover 1,000 sq. ft.?
30 bundles cover 1,000 sq. ft. Add 10–15% for waste = ~33 to 35 bundles.
Do I need starter shingles?
Absolutely. They seal the edge and protect against wind lift.
How long does it take to install?
For 2,000–2,500 sq. ft.:
- 1–2 days for pros
- 3–7 days for DIY
What’s a trusted resource for technique and safety?
Visit the IKO Roofing Shingle Installation Guide for professional product-specific instructions
