A residential roof is a system of many parts working together, not just the shingles you can see from the street. Here's a breakdown of the components that matter most, whether you're trying to understand a repair estimate or just curious what's actually up there.
The Roof Deck and Structure
- Rafters or trusses: the structural framework that supports the entire roof.
- Decking (sheathing): plywood or OSB panels fastened to the rafters that everything else attaches to.
- Ridge: the horizontal peak where two roof slopes meet at the top.
- Hip: the external angle where two roof slopes meet, running from ridge to eave.
- Valley: the internal angle where two slopes meet, channeling water downward.
- Eave: the lower edge of the roof that overhangs the exterior wall.
- Rake: the sloped edge of the roof at a gable end.
Waterproofing Layers
- Underlayment: a water-resistant layer installed over the decking, beneath the shingles.
- Ice and water shield: a self-adhering waterproof membrane used at vulnerable spots like valleys and eaves.
- Drip edge: metal flashing along the eaves and rakes that directs water into the gutters and protects the fascia.
- Starter strip: the first row of shingle material along the eave, sealing the roof's most vulnerable edge.
Flashing and Ventilation
- Step flashing: layered metal pieces used where a roof meets a wall, such as at a dormer.
- Chimney flashing: flashing custom-fit around a chimney to prevent leaks.
- Valley flashing: metal or membrane reinforcement in a roof valley.
- Pipe boot (vent boot): a rubber and metal collar sealing around plumbing vent pipes.
- Ridge vent: a ventilation component along the ridge that lets hot attic air escape.
- Soffit vents: intake vents under the eaves that pull in fresh air to balance attic ventilation.
Finishing Components
- Field shingles: the main body of shingles covering most of the roof.
- Ridge cap shingles: specially shaped shingles that finish off the ridge line.
- Fascia: the vertical board along the roof edge that gutters typically mount to.
- Gutters and downspouts: the system that collects and channels water away from the roof and foundation.
Want to see how these pieces fit together visually? Try the interactive Anatomy of a Roof tool on our Products & Brands page.
