Custom cross-section diagram of a house roof showing the many different parts of a residential roof including structural parts, the various layers, exterior and various roof features such as skylight and chimney.
Like many aspects of a home, a roof is fairly complex. There are quite a few parts of a roof on a home including different layers and features.
Below we created a very helpful custom diagram that illustrates the various features and layers of a typical roof. For more information about roofs, check out our types of roofs article and diagrams.
Ridge Board: A horizontal timber or metal resting at the peak of the roof. The rafters and trusses are connected to the ridge board for a cohesive framework.
Solid Decking: A composite decking made of solid materials. It resembles real wood and particularly strong and stable for bearing heavy load.
Felt Underlayment: It is a waterproofing layer made of regular felt, stacked above the solid decking board and then completely covered by the shingles or other roofing materials.
Shingles: Roof covering typically of flat and rectangular shapes and made of various materials such as slate, wood, flagstone, plastic, metal and composite materials.
Vent Pipe Flashing: An external installation on the roof that uses the vent pipe system to prevent water seeping in and create damage.
Skylight: A window installed on the roof or ceiling for the purpose of daylighting.
Chimney Flashing: A waterproofing seal installed at the intersection of the roof and chimney and used to prevent moisture penetration.
Chimney: A vertical structure through the roof that ventilates smoke and combustion gases from a fireplace, boiler or stove to the outside atmosphere.
Collar Beam: The horizontal beam connecting two rafters that intersect at the ridge.
Rafter: One of a series of diagonal members of the truss that meet at the apex in order to support the roof deck and its loads.
Valley Flashing: A waterproofing seal installed along the roof’s valley line.
Valley Underlayment: A waterproofing layer that protects the roof valleys from leaking.
Spaced Sheathing: Also called Skipped Decking, it refers to the installation of the flat panels by spaces apart and results to a ladder-type appearance.
Fascia: The sheath covering the ends of the rafters.
Lookout: The horizontal joist projecting in cantilever from the wall plate.
Rake: The inclined sides of a gable end.
Gutter: A duct for water discharge system for a building.
Downspout: The channel that transports rainwater from the gutter.
Splash Block: Found underneath the downspout and used to transport the rainwater from the gutter in a direction away from the house.
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