It is very hard to predict how long some roof system will last precisely. No matter how much professionalism, expertise and detailed reports are included in some roofing project, this is just not a precise science. So, to make a most efficient project and outcome as longest life service of some roof system it is important to understand some common agents that affect roof durability.
Including this factor, interior parts of the roof are usually saved in long-term condition, and in contrast, the exterior surface is much more affected by continuous thermal changes. Just knowing that air temperatures can vary from 38C in summer to a minimum of -27C in winter makes a clear picture about roof struggle. So it is best to accommodate the predicted thermal movements by making proper design and detailing of the roof needs. Temperature changes may increasingly accelerate irreversible consequences, such as influence on the moisture content, leaching actions, and crystallization.
Surface heating by infrared radiation and surface degradation by ultraviolet radiation are two particular wavebands that affect the life performance of roofing system. The infrared radiation is absorbed significantly by all forms of matter. This absorption is very dangerous as it influences that surface temperature becomes significantly greater than the surrounding air temperature. Starting from texture over color to opacity of the surface material absorption can have very different levels of infrared and solar radiation impact. UV radiation, on the other hand, has a very significant impact for the deterioration of some organic materials. Some combinations of temperature, sunlight and moisture cause even surface denudation of glass-fibre reinforced polyester rooflights which made manufacturers take measures in projecting future ones. Basic goals in producing proper withstanding materials today are to fight long-term ultraviolet degradation and infrared heating successfully.
Moisture is always present all around us starting from the form of water vapor to various form of its condensation. Even many surfaces that have proper covers and are greatly sheltered may become thoroughly wetted. Structural loading of snow and ice on a horizontal surface may cause some significant harmful property consequences. Especially when there are moments when snow is blown through small holes into hard reaching roof spaces. There is a wide range of materials that absorb moisture to very different degrees; sapwood even can absorb its weight in water. As condensation promotes the growth of surface molds, rot in timber, corrosion and accelerates many chemical reactions it is found as a significant enemy for roofing constructions. Also, water combined with other contaminants presents even more dangerous principal agent that cause deterioration to many roofing elements. Making available to roof to breathe and dry out by proper ventilation and keeping the water on distance significantly helps to prolong the life of any roof system.
Water turning to ice makes a significant expanding effect. This may create a lot of pressure on surroundings causing local cracking and seriously damaging. These cycles of changings from wet over freeze to thaw phases cause progressive and high-cost damages. Frost damage appears when water gets entrapped in material pores disrupting material in freezing phase. Luckily there are many materials now that have the power to absorb water, become saturated and successfully fight freeze-thaw actions. By designing, building, manufacturing components which can withstand in best possible way freeze-thaw mechanical stresses is still a great challenge for the roofing industry.