A roof assembly configured with the insulation below the deck, not typically in contact with the deck, allowing for a ventilation space. The temperature of the roof assembly remains close to the outside air temperature.
A flat roof is a type of covering of a building. In contrast to the sloped form of a roof, a flat roof is horizontal or nearly horizontal. Materials that cover flat roofs typically allow the water to run off freely from a very slight inclination.
Traditionally flat roofs would use a tar and gravel based surface which, as long as there was no pooling of water, was sufficient to prevent penetration. However, these surfaces would tend to fail in colder climates, where ice dams and the like could block the flow of water. Similarly, they tend to be sensitive to sagging of the roof reversing the subtle grading of the surface.
Modern flat roofs tend to use a continuous membrane covering which can better resist pools of standing water. These membranes are applied as a continuous sheet where possible, though sealants and adhesives are available to allow for bonding multiple sheets and dealing with structures penetrating the roof surface. Far more expensive flat roof options include sealed metal roofs using copper or tin. These are soldered interlocking systems of metal panels.
A single-ridge roof that terminates at gable end(s).
A roof that rises by inclined planes to form one or more hips.
Combination of two or more separate and distinct roof membranes; e.g., three ply smooth BUR and a modified bitumen cap.
A patented, proprietary variation of the “protected membrane roof assembly” in which Styrofoam® brand insulation and ballast are placed over the roof membrane. IRMA™ and Styrofoam® are registered trademarks of the Dow Chemical Company.
A continuous, semi-flexible roof membrane, consisting of multiple plies of felts, mats or fabrics laminated together with alternate layers of roof cements and surfaced with a liquid -applied coating with or without aggregate surfacing.
A category of roofs that generally include weatherproof membrane types of roof systems installed on slopes at or less than 3:12 (14 degrees).
A steeper roof that terminates into a flat roof at its high point.
Construction, usually set in mortar, of natural building stone or manufactured units, such as brick, concrete block, adobe, glass block, tile, manufactured stone or gypsum block.
An interlocking metal sheet having a minimum installed weather exposure of 3 square feet (279000 mm2 or 0.28 m2) per sheet.
Roofing materials whose surface or top layer consists of a granule-surfaced sheet.
A roofing assembly in which the membrane has been “spot affixed” to a substrate, usually with an adhesive or a mechanical device.
The addition of a new roof membrane or steep-slope roof covering over a major portion of an existing roof assembly. This process does not involve removal of the existing roofing.
The process of re-covering, or tearing-off and replacing an existing roof system
Coated felts, either smooth or mineral-surfaced.
(1) the cover of a building; (2) to cover with a roof.
An assembly of interacting roof components including the roof deck, vapor retarder (if present), insulation and roof covering.
The exterior roof cover or skin of the roof assembly, consisting of membrane, panels, sheets, shingles, tiles, etc.
The practice of removing an existing roof system down to the roof deck and replacing it with a new roofing system.
A system of interacting roof components, generally consisting of a membrane or primary roof covering and roof insulation (not including the roof deck) designed to weatherproof and, sometimes, to improve the building’s thermal resistance.
A roof having only one sloping plane and no hips, ridges or valleys.
A roofing system in which the principal roof covering is a single layer flexible membrane often thermoset or thermoplastic membrane.
A roof assembly configured with each component placed immediately on top of the preceding component; each component is in contact with the adjacent component. No space is provided for ventilation of the roof assembly. Also known as a “compact” roof assembly.