Thermal roof insulation is a type of building material that prevents cold air from entering the house and warm air from escaping, while also preventing moisture from accumulating in the ceiling. It is typically applied from the underside of the roof to prevent condensation and other damage. It is available in a variety of forms including spray, foam and batts. It is also available in a range of R-Values to suit different climate zones and budgets.
The main function of insulation is to slow the flow of heat, which means that it must have low thermal conductivity. This is achieved by trapping air or other gas inside pockets within a solid material such as wood, fiberglass, mineral wool and cellulose. The smaller the pockets, the more the material resists the flow of heat. This is why thicker materials offer higher R-Values than thinner ones.
It should also be water resistant to avoid the penetration of moisture into the interior walls, ceiling or roof space. This will help to prevent the build up of mould, mildew, fungi and other toxic substances that can affect human health. It should also be fire resistant and able to withstand heat from fireplaces, heaters, open flames or lightning strikes. It should also be able to resist impact, be creased and bent without losing its integrity and be compatible with other roofing components like flashings, tiles or metal roofs.
Thermal insulation is a long-term investment that will pay off in reduced energy costs over time. It can significantly reduce the amount of money spent on heating and cooling the home, as well as protect belongings from deterioration due to heat loss. The best insulation is one that combines the three major methods of heat transfer – radiation, convection and conduction – with a high R-Value to achieve maximum energy efficiency.
Generally, all materials conduct heat, but some are much worse than others. Metallic and glass-like materials such as aluminum, steel and concrete are good conductors, while wood, paper and fibrous materials such as cellulose, mineral wool and fiberglass are poor conductors. Insulation materials are also categorized as dense or fluffy based on their weight and texture. The lighter, fluffier and more porous the material, the less it conducts.
Most insulating materials are fitted between studs, joists and beams and are suitable for standard stud and joist spacing. They can be cut and shaped using power and hand tools, and are quick and easy to install. They are also very affordable.
While DIY kits are available for some types of insulation, it is recommended that you hire a professional for a quality job. This will ensure that the product is installed correctly and meets local building and safety codes. It is also important to follow the manufacturers’ installation instructions carefully and take any necessary safety precautions when attempting a do-it-yourself installation.
While it may be possible to apply some insulating products from the outside of the roof (sarking), this technique is usually only recommended for older buildings that have been constructed with a flat roof. It is also a lot more expensive than insulating from the inside, and is usually done as part of a complete roof renovation.