A shingle roof is about a dozen named parts, stacked in a set order. Knowing the names makes a quote readable, because almost every line on it is one of these.
Diagram
The parts of a roof, numbered
A cross-section through a typical shingle roof, in the order a roofer builds it.
Cross-section of a typical Triangle shingle roof. Numbers match the list below.
Rafters or trusses. The framing the roof sits on.
Decking. The plywood or OSB sheets nailed to the framing. Also called sheathing.
Underlayment. The water-shedding layer laid over the decking.
Drip edge. The metal edge that sends water past the fascia.
Starter strip. The first course along the eaves, with sealant at the edge.
Shingles. The field of the roof, laid in overlapping courses.
Ridge cap and ridge vent. Cap shingles over the peak, with the exhaust vent under them.
Fascia. The board along the eave that the gutter hangs from.
Gutter. Catches the water at the eave and sends it to the downspouts.
Soffit. The underside of the overhang, where the attic draws air in.
Flashing. Metal that turns water where the roof meets a chimney or wall.
Pipe boot. The collar that seals around a plumbing vent pipe.
Structure
What holds the roof up
The two parts you never see once the roof is on.
Rafters or trusses. Rafters are single sloped boards cut on site. Trusses are triangles built in a factory and set by crane, and they are common on newer houses. Our truss calculator works out the spacing and count.
Decking. Plywood or OSB sheets nailed across the framing. Everything else is fastened to it, so soft or rotten decking has to be replaced before a new roof goes on. Our sheathing guide covers what that costs and how it is found.
Waterproofing
The layers between the decking and the shingles
Underlayment covers the whole deck. What we specify is a 50-year synthetic across the roof, with self-adhering leak barrier in the valleys, along the eaves and around chimneys, skylights and walls, which is where water sits. Our underlayment guide compares five products, and the leak barrier calculator counts the rolls.
Drip edge is the bent metal along the eaves and rakes. It carries water past the fascia into the gutter instead of letting it wick back onto the wood. North Carolina's 2018 residential code dropped the model code's drip edge section, and the Office of State Fire Marshal confirmed in 2020 that it is required on shingles only where the manufacturer's instructions call for it. Which profile goes where is in our gutter apron vs drip edge guide.
Shingles
Starter, field and cap
Three kinds of shingle go on one roof.
Starter strip is the first course along the eaves and rakes, with a sealant line right at the edge so wind cannot get under the first row. Our starter shingles guide explains why cut-up field shingles are not the same thing.
Field shingles are the courses that cover the slopes. The types, from 3-tab to luxury, are compared in our guide to shingle types.
Ridge cap and hip cap are thicker shingles folded over the peak and down the hips. On most roofs here the ridge cap also covers the ridge vent, the slot along the peak where the attic lets hot air out.
Lines and edges
Ridge, hip, valley, eave and rake
The names for where slopes meet and where the roof ends.
Ridge: the level peak where two slopes meet. Hip: a sloped outside corner where two slopes meet. Valley: the sloped inside corner where two slopes meet, which carries more water than any other part of the roof.
Eave: the level bottom edge, where the gutter hangs. Its underside is the soffit, and our soffit and fascia guide covers both boards. Rake: the sloped edge up the side of a gable. Gable end: the triangle of wall under the rakes.
How many of these a roof has depends on its shape.
Want to know what shape your roof's parts are in?
A free inspection checks every one of them and puts it in a written report with photos.
Penetrations
Flashing, pipe boots and vents
Every hole in the roof and every wall it meets needs its own detail.
Flashing is the metal that turns water where the roof meets something else: step flashing up a sidewall, counter flashing over it, and a full flashing kit around a chimney or skylight. A lot of roof leaks start at the flashing, and our flashing guide shows each type.
Pipe boots are the rubber or lead collars around plumbing vent pipes. The rubber ones often crack in the sun before the shingles around them wear out.
Vents let the attic breathe, with air drawn in at the soffits and pushed out at the ridge or through roof vents. Our roof vent guide compares them, and the ventilation calculator sizes them.
On a reroof
Which parts get replaced
What comes off, what goes back new, and what usually stays.
Replaced every time: shingles, underlayment, starter, ridge cap, pipe boots and the ridge vent. These all come off in the tear-off and go back new.
Replaced as needed: decking where it is soft or rotten, flashing that will not come off clean, and drip edge that is bent or rusted.
Separate jobs: fascia, soffit and gutters. They are often done at the same time but quoted on their own lines, and our gutter page covers that side.
Taken from what Google already shows for this search.
What are the parts of a roof called?
From the inside out: rafters or trusses, decking, underlayment, drip edge, starter strip, shingles and ridge cap. Around those sit the flashing, the vents, and at the eaves the fascia, soffit and gutters. The lines where slopes meet are the ridge, the hips and the valleys, and the edges are the eaves and the rakes.
What is roof underlayment?
The layer between the decking and the shingles. It sheds any water that gets under a shingle and keeps the decking dry while the roof is open. Felt is the old version and synthetic is the modern one, and our underlayment guide compares five of them on cost.
What is the edge of a roof called?
Two names, depending on which edge. The level bottom edge where the gutter hangs is the eave. The sloped edge that runs up the side of a gable is the rake.
What is the peak of a roof called?
The ridge. On a hip roof the sloped lines running down from the ends of the ridge to the corners are the hips, and both get covered with cap shingles.
What is the most expensive part of replacing a roof?
The shingles and the labor to strip and lay them are the biggest lines on almost every quote. The line that surprises people is decking, because nobody knows how much is rotten until the old roof is off. Our roof sheathing guide explains how that is usually priced.
Is drip edge required in North Carolina?
Not by the residential code on its own. In a February 2020 interpretation of the 2018 NC Residential Code, the NC Office of State Fire Marshal confirmed the model code's drip edge section was deleted, so drip edge is required on asphalt shingles only where the manufacturer's installation instructions call for it.
Keep reading
Related guides and calculators
Each part above has its own guide. These are the ones people read next.
Every part on this page, replaced and written into one quote.
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