Through The Roof: Proper Heat Management With Insulation – Part 3: The Best Way To Insulate Your Roof

Living in a vacuum-sealed air conditioned box lined with insulation material simply isn’t an option, though it would be a great way to beat the heat. Fortunately, there are roof insulation methods and materials that have proven to be much better choices. Some insulation materials even boast of a lower environmental impact, such as those made from recycled paper, glass, or plastic bottles.

An excellent way to compare insulation materials is to look at the cost per R-value. The R-value of a material is how effectively it resists the heat flowing through it. The greater the value, the greater the resistance. It can also retain the heat gained from the sun a lot longer, and make it easier for heat to be let out through ventilation. Wool materials may not have the best R-values compared to that of polyurethane and polyisocyanurate foams — with 3 per inch for fiberglass and 3.8 for cellulose — but they do deliver good results at a much lower cost. More importantly, they are suitable even for tropical and subtropical climates.

Among these is glass wool, or fiberglass, which was invented in 1932–1933 by Russell Games Slayter of Owens-Corning as a material to be used as thermal building insulation. Not to be confused with the plastic composite material, glass wool is made from a mixture of natural sand and recycled glass that is then converted into fibers in a method similar to making cotton candy. This creates countless small pockets of air that can trap heat and result in high thermal insulation properties. The same principle is used in mineral wool or fiber made from molten — although usually synthetic minerals, such as slag and ceramics.

Cellulose insulation is another green alternative made from recycled paper and cardboard. It is heavier than fiberglass, however, so it needs to be prevented from clumping in walls and, as a result, losing its insulation value. This is why some manufacturers opt to treat cellulose with a small amount of adhesive.

Moisture- and fire-resistant chemicals, such as borate and ammonium sulfate, are often used to treat insulation to keep the roof cavity dry and help protect it from fire. As a precaution, however, it is not recommended to have anyone other than a certified roofing contractor install any insulation. Only by following recommended professional work practices can your loft or attic insulation be installed safely and properly.

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A contractor should be called in to either roll out the batts of insulation material or install the loose-fill form via a special machine, using a mechanical ‘blowing in’ process.