Roof insulation depends on the shape of the roof as there are mainly flat and pitched roofs. We choose the materials of the insulation in function of different purposes as heat, cold, noise, vibrations …© lightkeeper / 123RF Stockfoto
There is building insulation for any purpose. Although most insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and insulation against vibrations mostly caused by industrial applications. We use the insulation material for its ability to perform several of these functions at once.
As a roof has the function to protect people and furnishing from climatic elements, the insulating properties of a roof are deciding on its structure and the choice of roofing material.
Particularly natural fibrous materials, such as thatch, have excellent insulating properties. If the properties of the base material lack these insulating properties, extra insulation is often installed under the outer layer. In developed countries, the majority of dwellings have a ceiling installed under the structural members of the roof. This ceiling insulates against heat and cold, noise, dirt and often from the droppings and lice of birds who frequently choose roofs as nesting places.
Concrete tiles can be used as insulation. When installed leaving a space between the tiles and the roof surface, it can reduce heating caused by the sun.
Forms of insulation are felt or plastic sheeting, sometimes with a reflective surface, installed directly below the tiles or other material; synthetic foam batting laid above the ceiling and recycled paper products and other such materials that can be inserted or sprayed into roof cavities. So-called Cool roofs are becoming increasingly popular, and in some cases are mandated by local codes. Cool roofs are defined as roofs with both high reflectivity and high thermal emittance.
Poorly insulated and ventilated roofing can suffer from problems such as the formation of ice dams around the overhanging eaves in cold weather, causing water from melted snow on upper parts of the roof to penetrate the roofing material. Ice dams occur when heat escapes through the uppermost part of the roof, and the snow at those points melts, refreezing as it drips along the shingles, and collecting in the form of ice at the lower points. This can result in structural damage from stress, including the destruction of gutter and drainage systems.
As yet mentioned there are mainly two shapes of roofs: flat roofs and pitched roofs. For flat roofs, there are the options warm deck, cold deck or inverted roof. For pitched roofs, there is warm or cold loft insulation.