A more recent design is the installation of a roof deck with foil-backed foam along with a second deck that is air-gapped away from the foil-backed foam to allow air to flow vertically to a ventilation outlet at the peak of the roof—it is a double deck design with an air gap. This design improves efficiency.
Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Such roofs are built with mostly timber, take a number of different shapes, and are covered with a variety of materials.
There are four main types of roofers: shinglers, who primarily install shingles, shakes, tiles, and other nail-on products on roofs with 5:12 pitches or above; metal roofers, who focus on metal panels; single-ply or "flat" roofers, who focus on roofs such as single-ply or foam roofs; and "hot" roofers, who work using tar-based products. It is not uncommon, however, for companies to have their roofers service multiple styles and types of roofing; and certain manufactures will allow only pre-approved installers, thus making these four roofer types limiting. As per the application areas, roofing contractors can be categorized as Industrial or commercial roofers, Factory Shed roofers, Residential Roofers, Commercial roofers. Based on the types of the materials, roofing can be classified as terrace roofing, metal roofing, polycarbonate roofing, steel roofing, PVC roofing, skylight roofing. Pre-engineered companies installs roofing.
A roof is part of a building envelope. It is the covering on the uppermost part of a building or shelter which provides protection from animals and weather, notably rain or snow, but also heat, wind and sunlight. The word also denotes the framing or structure which supports that covering.