How to Shingle a Roof With Architectural Shingles

The order of work is the same on a house or a shed: drip edge and underlayment, a starter course, then straight, offset courses nailed in the right spot, flashed at every wall and finished with ridge cap. The details that cause leaks are the edges, the nail line and the flashing, so that is where this guide spends its time. Always follow the instructions printed on the bundle; they decide your warranty.

Before you start

• Check the pitch. Asphalt shingles need at least 2/12. Between 2/12 and 4/12 the IRC requires two layers of underlayment (or an approved equivalent). Measure yours with the roof pitch calculator.
• Tear-off or layover? Code allows at most one layer over one existing layer, and never over a damaged deck. See shingles over old shingles.
• Order materials. Most architectural shingles come 3 bundles to the square (100 sq ft), some heavier lines 4. Use the calculator below for bundles, starter, ridge cap, underlayment, drip edge and nails.
• Permit and safety. Many towns require a reroof permit. Use fall protection: roof anchors and a harness, or roof jacks with planks on steeper pitches.

For a shed (single-slope) roof, use the shingle calculator figures for one plane, or work it out by hand as in the shed example further down.

Step by step

1. Prepare the deck. Pull old nails flush, replace soft or delaminated sheathing, and sweep it clean. Shingles telegraph every bump underneath.
2. Drip edge at the eaves. Nail metal drip edge along the eaves first. Under the IRC, underlayment laps over the drip edge at the eaves.
3. Ice barrier where required. In areas with a history of ice dams, code requires a self-adhering ice barrier from the eave edge to at least 24 inches inside the exterior wall line. Many roofers also run it in valleys and around chimneys and skylights everywhere.
4. Underlayment. Roll synthetic or felt underlayment horizontally, starting at the eave and lapping each course over the one below, per the product's lap marks. On 2/12 to 4/12 roofs, install two layers as code requires.
5. Drip edge at the rakes. Rake drip edge goes over the underlayment so water running along the rake can't get behind it.
6. Starter course. Install starter strip along the eaves (and along the rakes if the manufacturer calls for it) with its sealant strip at the edge, overhanging the drip edge slightly, typically 1/4 to 3/4 inch. Don't use upside-down field shingles as starter on laminated shingles unless the instructions allow it.
7. Snap chalk lines. Snap a line for the top of each course, or every few courses, at the exposure printed on the wrapper. Most metric-size architectural shingles have a 5-5/8 inch exposure; some older or regional products use 5 inches. Snap vertical lines too, so the offsets stay true across the roof.
8. First course. Lay the first full shingles flush with the starter's bottom edge, starting at a rake and cutting the first piece if the instructions call for a starting offset.
9. Offset each course. Stagger the end joints from course to course by at least the minimum the manufacturer prints. It's commonly 4 to 6 inches or more for laminated shingles, and some lines need a specific stepped pattern to avoid visible zippers or repeating patterns.
10. Nail in the nailing zone. Drive nails flush (not cut into the mat, not angled) in the marked nailing area on the shingle: 4 per shingle normally, 6 where the instructions require it for high-wind warranties or steep slopes. Nails must penetrate at least 3/4 inch into the deck or go through it. A nail too high misses the shingle below; too low, it shows or leaks. See roofing nail size.
11. Valleys. Use an open metal valley or a closed-cut valley. Most makers of laminated shingles don't recommend woven valleys. Keep nails at least 6 inches from the valley centerline, and clip the upper corner of shingles that end in an open valley.
12. Walls, chimneys and pipes. Where a roof meets a sidewall, install step flashing with each course (the IRC calls for pieces at least 4 by 4 inches) and lap the siding or counterflashing over it. Use apron flashing where the top of a roof plane meets a wall, and new pipe boots at vents.
13. Ridge and hips. Finish with hip and ridge cap shingles made for the product line. Laminated field shingles can't be cut into cap pieces the way 3-tabs can. Leave the ridge vent slot open if the roof is vented at the ridge.
14. Clean up. Run a magnet over the yard and driveway for nails, and keep the bundle wrappers until the job is inspected and the warranty is registered.

Shingling a shed roof

A shed roof is a single plane, so it is the easiest roof to shingle, but it has two details a gable roof doesn't.

• Pitch. Sheds are often 2/12 to 4/12. That means double underlayment, and under 2/12 shingles aren't allowed at all; use roll roofing, a membrane or low-slope metal instead.
• The top edge. If the high side butts a wall, finish with apron (headwall) flashing tucked behind the siding or housewrap. If the high side is a free edge, trim the last course and cap it. Many roofers bend hip and ridge cap shingles over the edge, use a metal edge, or use a shed-ridge vent. Check the shingle maker's detail.
• Rakes. Both side edges are rakes, so drip edge goes over the underlayment on both, and starter along the rakes helps keep wind from lifting the edge shingles.

Mistakes that void warranties or cause leaks

What it costs

Materials for a typical house are a small part of a professional bid; labor, tear-off and disposal make up most of it. For a planning range for your roof size and material, use the roof replacement cost estimator, and if you're comparing contractor bids, see your roofing estimate, explained.

This guide summarizes common practice and model code (IRC) requirements for asphalt shingles. Your local code and the manufacturer's printed installation instructions take priority.

Last reviewed 2026-10-22. Results are estimates for planning; confirm quantities with your supplier and requirements with your local building code and the manufacturer's instructions.