Key takeaways
- Decking is the base that everything is fastened to.
- Underlayment and ice-and-water membrane are the backup that stops leaks.
- Flashing protects every joint and opening.
- Ventilation keeps the whole system dry and cool.
When people talk about a roof, they usually mean shingles. The shingles are only the top layer of a system.
Decking
Plywood or boards over the rafters. If the decking is soft, nothing fastened to it will hold.
Ice-and-water membrane
A sticky waterproof layer at the eaves, in valleys and around openings, where water is most likely to back up.
Underlayment
A synthetic or felt sheet over the deck that sheds any water that gets past the shingles.
Drip edge and starter
Metal along the eaves and rakes directs water into the gutter, and a starter strip seals the first course.
Shingles or panels
The visible surface that sheds most of the water and gives the roof its look.
Flashing
Metal at chimneys, walls, skylights, vents and valleys. Many leaks begin here.
Ventilation
Intake at the eaves and exhaust at the ridge move air through the attic. See our Roof Anatomy diagram on the home page to tap through each layer.
Related services
Questions about your own roof? Call or text 615-431-3789, or use the quote form below.