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“What is the best roof?”
Americans must demand more out of roofs to protect us from severe weather.
The ‘best roof’ depends on a wide variety of factors from geography and weather, to budget and aesthetic preferences, roof cover performance and its change over time. The Roofing Roadmaps is an IBHS strategic initiative to bring together the research on wind and hail performance of roofs to educate stakeholders on these factors and ultimately provide guidance on the best (and worst) roof systems.
Components of a Roof System
Drip Edge: A strip of metal flashing or overhanging component with a lower edge that projects slightly outward to divert water away from the roof and walls.
Eave: The edge of a roof that extends beyond the top of a wall.
Fascia: A horizontal board that runs along the eaves of a roof, often supporting the lower edge of a roof, as well as gutters.
Gables: The triangular section of a building wall formed where two roof faces meet.
Hip: The intersection of two roofing planes to form a fold or vertical ridge.
Pitch: The steepness, or slope, of the roof expressed as a ratio of the vertical rise to the horizontal run, in inches, (e.g., 4:12, meaning a 4-inch vertical rise for every 12 horizontal inches). The steeper the roof, the higher the vertical rise.
Rake: The edge of the sloped sides of a gable roof running from eave to ridge.
Ridge: The peak of the roof where two roof planes intersect.
Roof Assembly: A system designed to protect against weather and withstand design loads.
Roof Cover: The material applied to the roof deck for weather resistance, fire classification, or appearance.
Roof Deck: The flat surface, usually OSB or plywood, on top of the roof structure (rafters or trusses) supporting the roof cover.
Underlayment: An asphalt-saturated felt, synthetic, or other sheet material installed between a roof deck and roof covering.
