If someone decides that they want to install a cool roof to their industrial or commercial building, then they basically have a choice of three different types. These main categories (which can then also be broken down into their own sub-types) are inherently cool roofs, coated roofs and green roofs.
Inherently cool roofs are basically roofs that are covered in white vinyl and these are amongst the most highly reflective roofing materials available today. Roofs made of this thermoplastic white vinyl covering can actually reflect up to 80% of the sun’s rays, while being able to emit at the very least 70% of the heat the building absorbs through solar radiation. To put this into prospective, an asphalt roof will only reflect from 6-26% of all solar radiation, meaning that the interior of the building will get warmer and have all the associated costs that this entails to try and keep it cooler.
Traditionally, coated roofs used white paint as this proved to be very efficient at reflecting solar rays. Nowadays alternative methods are coming to the fore which offers substantially better reflective properties. One of these products is white paint based and contains a formulation of hollow glass microspheres which are known to increase reflective properties. This system is called Hyperglass Rubber Roof Coating.
Last but not least, the third category of cool roof is the so-called green roof. These types of roof usually consist of a an insulation layer, a waterproofed membrane, a layer for drainage which can be clay or gravel, a special filter that allows water to pass but doesn’t erode the soil above, and then the green life itself in the form of plants.
Green roofs themselves can be classed as either intensive or extensive, with some actually incorporating both. Intensive green roofs are, as the name implies, used for more advanced roof constructions and require at least one foot of top soil. They are usually multi-layered and have very elaborate drainage and irrigation systems and can be used for recreational purposes as they can support foot traffic. The downside to having this type of green roof is the fact that it adds a quite significant load onto the structure of the building, as well as requiring a very high level of maintenance.
On the other hand, extensive green roofs only require a very shallow layer of soil (usually less than six inches) and require much less maintenance. These are designed to accommodate smaller plant life such as grasses, mosses and wildflowers.
No matter which green roof category is chosen for a building, they both have some very good benefits. These include having a long life span, better air quality as the plants absorb carbon dioxide and emit oxygen, great insulation and finally, the main reason why people add this type of roof in the first place, a cooler environment.