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What’s the difference between organic and fibreglass shingles?


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What's the difference between fibreglass and organic shingles?  I have to re-roof my cottage this year, and I'd like to use long-lasting shingles.–Joseph Fobert, Cornwall, Ont.

‘Organic’ is the current word used to describe traditional asphalt shingles, which differentiates them from an up-and-coming alternative called fibreglass shingles. The two types of shingles look the same on your roof: coloured granules held together by hardened tar. Both types are flexible and both are applied in exactly the same way. The difference has to do with what the tar and gravel mixture is bonded to.

Organic shingles are built on a substrate of heavy felt, while fibreglass shingles have a foundation of non-woven glass fibres. This difference doesn’t sound like much, but it actually leads to substantially different performance, especially in particular situations.

The main advantage of fibreglass shingles is their resistance to heat. They’re much less likely to curl up than organic shingles, even when used on hot, unventilated roof structures. This means they will last longer, especially when you use higher-end products. The longest-lasting shingles I’ve seen are fibreglass and carry a 50-year warranty. Fibreglass shingles are also less susceptible to catching fire or melting from the heat of a fire below.

I’ve used fibreglass shingles, and I’ll use them again. In the case of your cottage, I also recommend covering the entire roof surface with a self-sticking ice/water shield before any shingles go down. If your cottage is subject to a lot of high winds and goes for months without a visit, a few torn shingles could mean water damage. The ice/water shield provides a much more durable secondary layer of defence against water damage than tarpaper ever could. If your cottage has roof valleys, I’d suggest weaving shingles over valleys instead of leaving valley flashing exposed. This approach is much more reliable, especially on a roof that will be exposed to ice and snow buildup. Woven valleys are also faster and easier to install.

Steve Maxwell

Steve Maxwell lives on Manitoulin Island, Ontario and has worked remotely as technical editor of Canadian Home Workshop since 1990. He uses his experience as a cabinetmaker, carpenter and stonemason to prepare projects for the magazine, to write stories of his own, and to test and review products and tools in his workshop. Steve has a readership of about 2 million people across Canada and the US, and takes photos and creates videos to accompany his work.

When Steve’s not working with words, wood and stone, he likes to spend time gardening, cutting firewood, and showing his five kids how to make things.

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Jul. 10, 2014

5:26 pm

Asphalt shingles are known to be quite durable as well as relatively affordable, especially compared with other shingle options. Some types can last up to 20 years. They are essentially made from felt or paper soaked in asphalt. The asphalt-soaked paper is then coated with an additional thick layer of asphalt, then a layer of ceramic granules. Because of this, the shingle is waterproof and withstands weather elements very well.

Fiberglass shingles do contain some asphalt, but less of it than organic shingles. Fiberglass shingles feature a mat that is made of wet fiberglass held together with a urea-formaldehyde resin. The mat is soaked with asphalt filled with mineral fillers, which makes it waterproof.


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