Your roof is much more than the shingles you see from the street. Knowing the main parts helps you understand an inspection, compare quotes, and spot problems early.
01
The Shape of the Roof
1. Ridge
The peak where two roof slopes meet, usually capped with special ridge shingles and often vented.
2. Hip
The sloping edge where two roof planes meet on the outside corner of a hip roof.
3. Valley
The inside angle where two slopes meet. Valleys channel lots of water, so they need careful sealing.
4. Gable
The triangular wall section at the end of a pitched roof.
5. Dormer
A structure that projects from the roof with its own window and small roof.
6. Eave
The lower edge of the roof that overhangs the walls.
7. Rake
The sloped edge of a gable roof.
02
Under the Shingles
8. Rafters / trusses
The framing that supports the whole roof.
9. Decking (sheathing)
The plywood or OSB boards nailed to the rafters — the base everything else sits on.
10. Underlayment
The water-resistant layer between the decking and the shingles.
11. Ice-and-water shield
Self-adhering membrane in leak-prone spots like valleys and around penetrations.
12. Shingles or panels
The outer covering — asphalt shingles, metal, tile or a flat-roof membrane.
03
Edges, Seals and Drainage
13. Flashing
Metal strips that seal joints around chimneys, walls, skylights and valleys. Most leaks start here.
14. Drip edge
Metal edging at the eaves and rakes that directs water into the gutters and away from the fascia.
15. Fascia
The board along the roof edge that the gutters attach to.
16. Soffit
The underside of the overhang, often vented to bring air into the attic.
17. Gutters and downspouts
Collect runoff and carry it away from the foundation.
18. Vents
Ridge, box, turbine or soffit vents that keep air moving through the attic, reducing heat and moisture.
04
Why It Matters
When a roofer says your "step flashing is lifting" or your "decking is soft near the valley", you'll know exactly where to look — and you'll be in a better position to judge whether a repair or a replacement makes sense.
