How to Shingle a Roof: Technique, Nailing and Courses
The specific craft of laying asphalt shingles, starter course, offset pattern, the nail zone, valleys and ridge cap, plus how to replace a few damaged shingles the right way.
Scope note: this guide focuses on the shingling technique itself. For the whole reroofing project, tear-off through cleanup, see our how to roof a house guide. As always, a shed or small outbuilding is a reasonable place to learn; the main house, with its height, valleys and flashing, is usually a job for a pro.
In this guide
Before you lay a single shingle
Good shingling starts with everything underneath being right, because shingles laid over a poor foundation will fail no matter how neatly they go on. Before the first shingle, the deck must be sound and dry, the drip edge installed along the eaves, ice and water shield laid in the valleys and along the eaves in cold climates, and synthetic underlayment rolled across the whole deck and lapped correctly. With that base in place, snap horizontal chalk lines up the roof as guides, because keeping every course straight is what separates a professional looking roof from a visibly crooked one, and even a small drift compounds over many rows.
Have your materials staged and your tools ready: a roofing nailer or hammer, plenty of hook blades for your utility knife, a chalk line, and the correct roofing nails, long enough to penetrate through the shingle and underlayment and well into the deck. Getting the preparation right, and understanding the layered system you are building on, which our parts of a roof guide lays out, is what makes the shingling itself go smoothly and last. Rushing the base to get to the visible shingles is one of the most common ways an amateur roof goes wrong.
The starter course
The first course of shingles is not a normal shingle course, and skipping the proper starter strip is a classic amateur mistake that leads to wind damage. A starter strip runs along the eaves beneath the first visible course, providing an adhesive strip right at the edge that seals the bottoms of the first shingles down so wind cannot get underneath and lift them. It also fills the gaps between the tabs of the first course so water cannot run through to the underlayment at the vulnerable edge. You can buy dedicated starter shingles or make starter from field shingles per the manufacturer instructions, but you should never simply start with a normal shingle course flipped or unmodified, because that leaves the sealant in the wrong place.
Install the starter along the eaves, overhanging the drip edge slightly per the manufacturer specification so water drips cleanly into the gutter, and along the rakes as well on many systems. Getting this first, hidden course right sets up the whole roof to resist wind and shed water at its most exposed edge, which is exactly where roofs are most likely to fail. It is a small step that amateurs skip and professionals never do.
Laying the field courses
With the starter in place, you lay the field shingles, the main visible area of the roof, working upward in overlapping horizontal courses from the eaves to the ridge. The two things that matter most are the offset and the alignment. Each course must be offset, staggered, from the one below so that the joints between shingles never line up vertically, because aligned joints would give water a straight path down to the underlayment. Manufacturers specify an offset pattern, often half a tab or a set measurement, and following it produces both a watertight roof and the pleasing random appearance of a good shingle job. Use your chalk lines to keep each course straight and properly exposed, meaning the right amount of each shingle is left visible below the course above.
Work across and up the roof methodically, keeping your courses level and your offset consistent. The exposure, how much of each shingle shows, is set by the manufacturer and affects both appearance and weathertightness, so do not improvise it. As you reach the edges, shingles are trimmed to the rake with a utility knife. The rhythm of a good shingle job is repetitive and precise, and maintaining that consistency course after course is what gives you a roof that both looks right and keeps water out for its full lifespan. Our asphalt shingle guide covers the material side of what you are installing.
The nail zone: where most roofs fail
If there is one technique to get right, it is nailing, because incorrect nailing causes more shingle roof failures than anything else. Every shingle has a designated nail zone, a marked strip, usually just below the adhesive line, where the nails must be driven so that each nail catches both the shingle you are fastening and the top edge of the shingle in the course below. Nails placed too high miss that overlap and hold only one shingle, which lets shingles blow off in wind. Nails driven too low are exposed to the weather and leak. The number of nails matters too: four per shingle is standard, and six per shingle is required in high wind areas and by many manufacturers for the warranty.
Just as important as placement is how the nails are driven. A nail should sit flush, snug against the shingle, not overdriven so the head cuts through the material and breaks the seal, and not underdriven so it stands proud and stops the next course from lying flat. With a roofing nailer, the air pressure has to be set correctly and checked often, since it drifts. Getting the nail zone, the count, and the depth right on every shingle is tedious and it is exactly what amateurs get wrong and professionals get consistently right, and it is the difference between a roof that survives a storm and one that peels.
Valleys and penetrations
Valleys, where two roof planes meet, and penetrations like vent pipes and chimneys are the trickiest part of shingling and where leaks most often begin. Valleys carry a concentrated volume of water, so they need ice and water shield beneath them and careful shingling, either woven, closed cut, or with metal valley flashing, done to the manufacturer method rather than improvised. Around penetrations, the shingles are cut to fit and integrated with the proper flashing and boots so that water is always directed over the top of the next layer, never allowed to run behind it. As our flashing guide stresses, these details must be flashed, not caulked, because caulk is not a substitute for proper integrated flashing.
This is precisely the part of shingling that separates a simple shed, which usually has no valleys or penetrations to speak of, from a real house roof, which has several. It is also where a do it yourself shingle job most often goes wrong, and where the consequences, a hidden leak into the home, are most serious. If your roof has valleys, a chimney, skylights or multiple vents, that complexity is a strong argument for professional installation, since the flashing and valley work require experience to get right.
The tools and pace that get it right
Shingling well is as much about the right tools and a steady, consistent pace as it is about knowledge. A pneumatic roofing nailer speeds the work enormously over a hammer, but only if its pressure is set correctly and rechecked often, since drifting pressure is what causes the overdriven and underdriven nails that undermine an otherwise good roof. A sharp utility knife with plenty of fresh hook blades makes the countless trimming cuts clean, a chalk line keeps every course honest, and a good roofing shovel or bar handles the tear off if you are reroofing. Beyond tools, the safety gear, a stable ladder, a harness on anything but the lowest roof, and grippy footwear, is not optional, because shingling means hours moving around at height.
The pace matters because shingling is repetitive precision work, and consistency across hundreds of shingles is what produces a roof that both looks right and performs. Professionals make it look fast because experience has made the repetitive motions automatic, but the underlying attention to the nail zone, the offset and the exposure never lapses. For a do it yourselfer, the lesson is to work deliberately and check yourself often rather than trying to match a pro crew is speed, since a shingle roof rewards care and punishes the shortcuts that creep in when you rush. This steady precision, sustained course after course, is ultimately what a good shingle job is made of.
Finishing the ridge
The roof is completed at the top with ridge cap shingles, which cover the peak where the two planes of field shingles meet. Ridge caps are individual shingles, either purpose made hip and ridge caps or field shingles cut down per the manufacturer instructions, bent over the ridge and nailed so each overlaps the next, working in the direction away from the prevailing wind so the laps shed water and wind. On most modern roofs the ridge is also where the attic ventilation exhausts, so a ridge vent is installed beneath the cap, an important detail covered in our roof ventilation guide, since good ventilation is central to how long the new roof will last. The final ridge caps are sealed and the last nails placed carefully, since the ridge is a prominent, exposed line.
Finishing the ridge well, straight, evenly lapped, and integrated with ventilation, is the crown of a good shingle job and the last chance to get the details right. A sloppy ridge is both unsightly and a potential leak point at the very top of the roof. With the ridge capped, the field laid, the valleys flashed and the starter sealed, the shingle roof is a complete, watertight system, provided every one of those steps was done to specification.
Replacing a few damaged shingles
A common smaller job is replacing a few shingles damaged by wind or impact rather than reshingling a whole roof, and while more approachable, it still has to be done correctly. The trick is that each shingle is held by its own nails and by the nails of the course above driven through its top edge, so to remove one you carefully break the sealant bond above and below it, lift the shingles above, remove the nails holding the damaged shingle and the nails above it that pass through it, slide the old shingle out, slide the new one into the same position, and renail in the correct nail line before resealing. Done in mild weather when the sealant is pliable, this is manageable; forced in cold weather, the brittle shingles crack.
The common mistakes are cracking surrounding shingles while lifting them, failing to renail in the proper nail line, and leaving nails exposed, any of which creates a new leak. For a shingle or two on an accessible, low roof this is a reasonable repair, but for anything near a valley, chimney or skylight, or on a steep or high roof, it is worth calling a professional, as our roof repair service handles. A botched shingle replacement can turn a small cosmetic issue into a leak, so if in doubt, it is a job for someone who does it regularly.
How to shingle a roof FAQs
How do you shingle a roof?
Over a sound deck with drip edge, ice and water shield and underlayment, install a proper starter course along the eaves, then lay field shingles upward in overlapping courses, staggering the joints per the manufacturer offset and keeping courses straight with chalk lines. Nail each shingle in its nail zone with four to six nails, flash the valleys and penetrations, and finish with ridge cap over ventilation.
Where do you nail shingles?
In the designated nail zone, a marked strip usually just below the adhesive line, so each nail catches both the shingle you are fastening and the top of the one below. Nails too high hold only one shingle and let it blow off; nails too low are exposed and leak. Use four nails per shingle normally and six in high wind areas.
How many nails per shingle?
Four nails per shingle is standard, and six per shingle is required in high wind areas and by many manufacturers to keep the warranty valid. The nails must be placed in the nail zone and driven flush, not overdriven through the shingle or left standing proud.
How do you replace a few damaged shingles?
Break the sealant bond above and below the damaged shingle in mild weather, lift the shingles above, remove the nails holding the damaged one and the nails above that pass through it, slide it out, slide the new shingle in, and renail in the same nail line before resealing. Avoid cracking surrounding shingles and never leave nails exposed.
Why do my shingles keep blowing off?
Almost always a nailing or starter problem. Nails placed above the nail zone hold only one shingle instead of two, and a missing or improper starter course leaves the first row unsealed, both of which let wind lift the shingles. Correct nail placement, the right nail count, and a proper starter strip are what keep shingles down in a storm.
What is the offset or stagger when shingling?
The offset is how much each course of shingles is shifted sideways from the course below so the vertical joints never line up. Aligned joints would let water run straight down to the underlayment, so manufacturers specify an offset, often half a tab or a set measurement, that produces both a watertight roof and the pleasing random look of a good shingle job.
What is shingle exposure?
Exposure is the portion of each shingle left visible to the weather after the course above overlaps it, and it is set by the manufacturer. Getting the exposure right, using chalk lines to keep it consistent, matters for both appearance and weathertightness, so it should be followed to specification rather than improvised.
Want it shingled right the first time?
The details, nailing, starter, valleys, ridge, are where shingle roofs succeed or fail. We install to manufacturer spec and register your warranty. Get a free, no pressure quote.
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