What You Need Before You Start
Roof shingle installation requires specific tools, materials, and safety equipment. Before you climb onto the roof, gather everything on the ground so you are not making trips up and down. You will need a hammer or pneumatic nailer, a utility knife, a tape measure, a chalk line, roofing nails (typically 1¼ inch), shingles themselves, roofing cement or adhesive, and a ladder rated for your weight plus 250 pounds.
Safety equipment is not optional. Wear a harness attached to a roof anchor or ridge strap, non-slip shoes with good grip, and work gloves. If you are working on a steep pitch (over 6:12 slope), a harness is essential — falls from roofs are the leading cause of serious home injuries. If the roof is wet or icy, wait for dry conditions. Do not work alone.
Check the weather forecast before starting. Shingles install best when the temperature is between 50°F and 85°F. Cold shingles become brittle and crack; hot shingles are too soft and can tear. Rain will wash away the adhesive seal before it sets, so plan for a full dry day with no rain in the forecast.
Key Takeaways
- Shingles must be nailed in a specific pattern — typically four nails per shingle in the nail strip, or six nails if the roof pitch exceeds 8:12 — or they will lift in wind.
- The first course (bottom row) is installed upside down as a starter strip, then covered by the first visible row of shingles.
- Each shingle overlaps the one below it by 5 inches, and each row is offset so seams do not line up vertically.
- Nails must go through the nail strip marked on the shingle, not above or below it, or the shingle will not seal properly and will blow off in wind.
- Ridge caps (shingles that cover the peak) are installed last and require a different nailing pattern than field shingles.
Preparing the Roof Deck and Underlayment
Before the first shingle goes down, the roof deck must be clean, dry, and solid. Walk the roof and look for soft spots, which indicate rot underneath. Press on the deck with your foot — it should not give. If you find soft areas, those boards must be replaced before you shingle over them, or the shingles will fail prematurely.
Underlayment (also called roofing felt or synthetic barrier) goes down next. This is the waterproof layer between the deck and the shingles. Roll it out horizontally, starting at the eaves and working toward the peak. Overlap each row by 4 to 6 inches and nail or staple it every 12 inches along the edges and seams. At the eaves, the underlayment should hang slightly over the edge so water drains into the gutter, not behind it.
Drip edge (a metal strip that channels water) is nailed along the eaves and gables on top of the underlayment. This prevents water from running under the shingles and into the fascia board. Nail it every 12 inches with roofing nails.
Installing the Starter Strip and First Course
The starter strip is a row of shingles installed upside down along the eaves. Cut full shingles in half lengthwise (so each piece is about 12 inches tall instead of 36 inches) and nail them with the adhesive strip facing up. Use four nails per shingle piece, spaced evenly. This starter strip gives the first visible row something to grip and prevents water from running up under the shingles.
The first visible course goes on top of the starter strip, right-side up. Snap a chalk line 5 inches above the eaves to keep this row straight — shingles are not perfectly uniform, and a chalk line prevents the row from drifting upward as you work. Nail the first shingle at the corner, then work across. Each shingle gets four nails driven through the nail strip (the dark band printed on the shingle). Do not nail above or below this strip.
Offset the second course so the seams do not line up with the row below. Most roofers start the second row with a shingle cut in half lengthwise, so the seams are staggered by half a shingle width. This pattern continues up the roof and prevents water from finding a straight path down through the seams.
Nailing Pattern and Spacing for Field Shingles
The nail pattern is the most common mistake in DIY roof installation. Each shingle has a nail strip — a dark band with small rectangular marks showing exactly where nails should go. On a standard roof (pitch 4:12 to 8:12), drive four nails per shingle, one in each marked spot. On steep roofs (over 8:12 pitch), use six nails per shingle to resist wind uplift.
Nails must be driven straight and flush with the shingle surface — not so deep that they tear the shingle, and not so shallow that they stick up. A nail that sticks up will catch water and cause leaks. A nail driven too deep will tear the waterproof layer and create a leak point. The nail head should sit just barely below the surface of the shingle.
Space shingles so they align vertically with the row below. Most shingles are 36 inches wide and have three tabs (the visible sections). Each tab is 12 inches wide. When you offset by half a shingle, the seams in the second row fall in the middle of the tabs in the first row, creating a brick-like pattern that sheds water efficiently.
Working Around Obstacles and Roof Features
Chimneys, vents, and skylights require special treatment. Shingles are cut to fit around these obstacles, and the gaps are sealed with roofing cement and flashing (metal pieces that direct water away from the opening). Flashing is installed before the shingles that cover it, so water runs down the flashing and onto the shingles below, not behind them.
At a chimney, for example, the flashing on the uphill side (the side facing the peak) is installed first, then shingles are laid over it. The flashing on the downhill side is installed after the shingles, so water running down the roof hits the shingles first, then the flashing, then continues down the roof. This order prevents water from pooling behind the chimney.
Roof vents (for bathroom exhaust or attic ventilation) have a flange that sits under the shingles above and over the shingles below. Install the vent flange, then shingle over the top portion and under the bottom portion. Seal all edges with roofing cement rated for your climate.
Installing Ridge Caps and Finishing the Peak
Ridge caps are shingles that cover the peak where two roof planes meet. They are installed last, after all field shingles reach the peak. Ridge caps are typically made from the same shingle material, cut into individual tabs (one tab per cap). Each cap overlaps the one below it by about 5 inches, just like field shingles.
Ridge caps require six nails per cap on standard roofs and eight nails on steep roofs, because the peak is the most exposed to wind. Two nails go on each side of the cap, driven through the shingle into the roof deck below. The nails must go through the nail strip, just as with field shingles. After nailing, cover each nail head with roofing cement to seal it.
Work from one end of the ridge to the other, overlapping each cap by 5 inches. The last cap at the peak is cut and sealed with roofing cement on all edges to prevent water from entering. Some roofers use a ridge vent (a porous strip that allows attic air to escape) instead of solid ridge caps — if that is your plan, install the vent before the caps and shingle over it.
Common Installation Mistakes and How to Avoid Them
Nails driven above or below the nail strip are the most common error. These nails do not hold the shingle down properly, and the shingle will lift in wind. The nail strip is printed on every shingle for a reason — use it. If you cannot see the nail strip clearly, mark it with a pencil before you start nailing.
Insufficient overlap is another frequent problem. If the overlap is less than 5 inches, water can run up under the shingles during heavy rain or when wind drives rain sideways. Measure the overlap as you go, especially on the first few rows. Once you establish the correct height, snap chalk lines every few rows to keep the pattern consistent.
Nailing too many times per shingle or in the wrong spots wastes nails and can actually weaken the shingle by creating extra holes. Stick to the pattern: four nails on standard roofs, six on steep roofs, all in the marked strip. Do not add extra nails "for safety" — they do the opposite.
Working in cold weather causes shingles to crack and split. If the temperature is below 50°F, the asphalt in the shingles becomes brittle. If you must work in cool weather, leave the shingles in the sun to warm them, or store them indoors overnight so they are pliable when you install them.
Frequently Asked Questions
How many nails does each shingle need?
Standard roofs (4:12 to 8:12 pitch) use four nails per shingle, all driven through the nail strip. Steep roofs (over 8:12 pitch) use six nails per shingle to resist wind uplift. The nail strip is marked on the shingle — follow those marks exactly.
What if I nail through the shingle above the nail strip?
The shingle will not seal properly and will lift in wind. Nails must go through the nail strip or the adhesive seal does not set up. If you drive a nail in the wrong spot, pull it out, fill the hole with roofing cement, and drive a new nail in the correct location.
Can I install shingles in cold weather?
Shingles become brittle below 50°F and will crack or split when nailed. If the temperature is below 50°F, warm the shingles in the sun or indoors before installation. Check the forecast — if it will be cold all day, wait for warmer weather.
How much should each row overlap the one below?
The overlap should be 5 inches. This means the top of the shingle below is covered by 5 inches of the shingle above. Measure this on the first few rows and snap chalk lines to keep it consistent. Insufficient overlap allows water to run up under the shingles.
Do I need to use roofing cement on every shingle?
Most modern shingles have a self-adhesive strip that activates in warm weather, so cement is not needed on field shingles. However, use roofing cement on ridge caps, around flashing, and on any nail heads that are exposed. In cold climates, some roofers add cement under the first course for extra security.