Select the right asphalt shingles

There are various asphalt shingle models to choose from. Here are a few tips to help you make the right choice.

Two different types of asphalt shingles

Easy to install, asphalt shingles account for more than 75% of all roofing materials installed. As well as protecting the roof, new shingles offer energy efficiency and cooling performance.
There are two main categories of asphalt shingles: organic and fibreglass.

Organic Shingles

These are the oldest type of asphalt roofing tiles. They consist of a cellular fibre substrate (recycled paper) impregnated with asphalt and compressed under high pressure.

More flexible than fibreglass shingles, they are easier to install in cold weather, more tear-resistant and able to better hide imperfections on the roof's deck. Heavier and therefore more resistant to strong winds, they also withstand changes in temperature.

Fibreglass Shingles:

Nowadays, most asphalt shingles have a layer of glass fibres instead of paper. They are referred to as composition shingles. Fibreglass shingles are lighter than their organic counterparts, because less asphalt is used during manufacturing. They are less expensive, more heat-resistant and the ''feet'', or notched ends, are less likely to lift, a problem often encountered on older roofs.

The fibreglass mat is surfaced with an asphalt coating, followed by mineral granules. An underlayment of asphalt-saturated felt should be installed over the roof structure prior to laying fibreglass shingles.

Asphalt shingles components

Asphalt shingles are composed of several layers. Here is a description of each of them.
  • Granular Surface Layer: Granules constitute the superficial layer of asphalt shingles. They provide colour and UV protection. This granite-like coating comes from basaltic deposits, including basalt and rhyolite, which are not only hard and durable but opaque to keep UV rays from deteriorating the asphalt. Certain granules are engineered to reflect heat and keep roof temperatures cool. They may also contain additives to prevent mould.
  • Asphalt Coating: Asphalt is the waterproofing agent applied during manufacture, ensuring the roof's protection. The thickness of the asphalt layer determines the weight of the shingle. Architectural shingles have two layers of asphalt, with a fibreglass mat in the centre.
  • Base or Mat: The material used for the base, or mat, differentiates the type of shingle. The base for organic shingles is made of organic felt saturated with asphalt, whereas the fibreglass shingles are reinforced with a fibreglass mat. This membrane acts as a frame, holding the other layers together; it must be very resistant and stable in all temperatures.
  • Adhesive Tabs: Shingles come with heat-activated adhesive tabs. Never drive a nail through these adhesive tabs, which could prevent shingles from fusing or locking to the roof deck.
  • Nailing Strip: Shingles must be nailed and not stapled, which makes them more vulnerable to cracks. Nail heads should be visible on the surface without being driven too deep.

Other interesting features

  • Wind-Resistance: The combination of adhesive and nails provide shingles with wind-resistance. The majority of shingles can resist winds more than 100 km/ h, and high-performance shingles provide protection and resistance to winds up to 220 km /h.
  • Solar Reflectance Index (SRI): New technologies have been developed making shingles more solar-reflective, and ensuring cooler attic spaces. The granular layer reflects the sun's rays without affecting roof-colour.

Pro Tip

Asphalt shingles contain a great deal of bituminous concrete used for asphalt production. New programmes have been introduced to collect and use them for road resurfacing. You can now get rid of old shingles by bringing them to your local Ecocentre. We advise calling the centre to find out if shingles are in fact recycled in your region.

Each model has different features (thickness, durability, function). With the increased occurrence of major weather disruptions, such as heavy rain and strong winds, manufacturers have improved their products to make them more resistant to extreme weather conditions. Weather-Tite technology provides protection against high winds (up to 220 km/h) due to the application of sealant bands on shingles. Manufacturers also offer products more resistant to heavy rain.

Roof slope

The slope or pitch of a roof dictates the type of shingles you should install. For a low-slope roof such as 4:12 to 2:12, three-tap shingles are preferable. Low-slope roofs are more susceptible to ice and water problems such as ice dams, so better flow properties are important to consider for installation.

For an average-slope roof (more than 6:12) or high-slope roof (8:12 to 12:12), architectural shingles are recommended.

Asphalt shingles should never be installed on roofs with a slope less than 2:12 (8.5°).

How to estimate quantities

For a roof with two slopes, add the surface area of the two slopes plus 10% to cover the crest of the roof. This 10% also enables you to cover any losses. The percentage is higher in the case of a roof with several slopes with ridges, verges and valleys. The manufacturer or retailer is a good resource-person to estimate the exact quantity you'll require.

For laminated shingles, the calculations are different. You need to add the surface of the two slopes plus only 5 to 7%. This excess consists of three-tab shingles, needed to cover the crest of the roof. To help you with your calculations: each package of three-tab shingles covers 30 linear feet.
Roofing calculator

Installation : how it's done

Installing shingles on a simple roof with two slopes is fairly straightforward and can be done by homeowners. When a roof is composed of several slopes, with valleys, ridges and verges, the work should be entrusted to professionals.
If you are installing shingles on an existing house, make sure the sheathing (decking), underlayment and eaves protection sheet are all sound. Flashings and drip edges should also be replaced and installed using the plastic cement for this purpose.
Installation sequence of materials:
  • Perimeter drip edge
  • Eaves protection sheet and underlayment
  • Valley and chimney flashings; gable drip edge
  • Shingles and vents
For detailed instructions, see our DIY How to Install Asphalt Shingles.

If you wish to entrust your project to professionals, contact us.

A few maintenance tips

Maintenance is important in order to increase the lifespan of your roof.
  • Inspect your roof every two or three years, though not more often since every time you walk on the roof you cause some damage;
  • Inspect the attic. Check that the insulating wool is dry, as well as the wood. Humidity may be due to inadequate attic ventilation.
  • Check that the plastic cement under the flashings is in good condition.
  • If you see cracks or a joint without caulk, use a caulking gun with a tube of plastic glue to do the necessary waterproofing.

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