Climate ready measures: Roofs

Roofs

These climate ready measures can protect your roof and the rest of your home from damage caused by the following climate hazards. The most important aspects of a climate ready roofing system are a durable sheathing material that is securely fastened to the roof structure, roofing underlayment, and installation of a climate ready roofing material.

Roofing materials

Comparative summary of roofing materials

When it is time to replace your roof, there are several roofing material options to consider. The tabs below provide a description of different roofing materials, including some potential co-benefits of each material, as well as a comparison of their cost relative to the least expensive option (i.e. Standard 3-tab asphalt shingles). Materials are listed from least to most expensive.

Asphalt shingles

Asphalt shingles (Standard 3-tab Class A inorganic shingles) are a popular and inexpensive roofing option. They do well in moderate wind conditions and most hailstorms because they are flexible and have a low risk of damage when debris makes contact with the roof. However, a severe storm can cause significant damage to asphalt shingles.

Most asphalt shingles have a Class A fire resistance rating, which is the highest level of fire resistance. With a flame-retardant fiberglass core, these shingles provide excellent fire resistance. Most products have a life expectancy of up to 20 years. 

Laminated architectural asphalt shingles

A type of asphalt shingle built with a heavier base and multiple layers of a more refined type of asphalt. Laminated architectural shingles have the strength of multiple standard asphalt (3-tab) shingles and can withstand stronger winds and more intense weather conditions.

Class 4 (impact resistant) shingles provide improved impact resistance, and increased resistance to tears, splits and hence water damage. Nevertheless, when exposed to large, wind-driven hail, impact resistant asphalt shingles can still experience damage.

Installed costs*

Laminated architectural shingles

+25% compared to standard asphalt

Class 4 impact resistant

+45% compared to standard asphalt

White (cool) shingles

Cool roof shingles have been engineered to reflect sunlight and decrease the amount of heat transferred into your home, reducing heat stress and cooling bills in summer months.

Lighter surfaces, if used throughout a region/neighbourhood, may also assist in reducing urban heat island.

A cool roof system can also be achieved by using light coloured roofing materials or painting your roof white.

Installed costs*

+45% compared to standard asphalt

Rubber

Rubber roofs are one of the most climate resilient roofing types, as they offer a tremendous level of impact resistance. They can handle heavy rain, heavy snow and extreme temperature variances that can cause splitting, peeling, cracking and rotting in other roofing materials.

Rubber roofs offer some fire resistance, but can be treated with fire-retardant to reduce their combustibility.

They can last 30-50 years, requiring little maintenance if installed correctly. Rubber roofs can be made from recycled tires, sawdust, and slate dust, making them an eco-friendly option. 

Installed costs*

+80% compared to standard asphalt

Metal roofs (aluminum and steel)

Metal is a durable, fire-resistant and lightweight roofing option that lasts up to four times longer than asphalt shingles. Metal roofs can withstand and provide protection against:

  • high winds;
  • winter storms;
  • snow and ice formation – ice slides right off;
  • water leaking into your home;
  • heat – reflecting heat from the sun;
  • fire, and
  • hailstorms.

Note: You can be left with visible dents if hail is a substantial size, but dents do not affect the rest of the roof below.  Steel can resist hail better than aluminum.

Metal roofing is often made from recycled metals making it an eco-friendly option.

Installed costs*

Steel

+185% compared to standard asphalt

Aluminum

+215% compared to standard asphalt

Wood shingles (Class B fire resistant)

Wood shakes and shingles are typically made from western red cedar and come in a variety of types and grades, categorized according to their level of resistance to wind, impact and fire.

Wood shakes and shingles provide good insulation and protection from extreme temperatures, reducing annual energy costs. They are also fairly durable and are not affected by things like hail.

If considering wood shakes or shingles, look for a minimum of Class A or B fire resistance.

Installed costs*

+245% compared to standard asphalt

Green (living) roof

A green roof consists of a thin layer of soil, with live plants growing on the top of your house. They are lightweight and can typically be installed on flatter roofs with a pitch from 0 to 30 degrees.

Green roofs have many benefits:

  • keep your home cooler during extreme heat events, reducing cooling costs by as much as 25%
  • reduce heating costs
  • reduce stormwater runoff from your property
  • improve local air quality
  • reduce urban heat island effect
  • resistant to strong winds and hail

In addition, green roofs capture and store carbon, provide habitat and biodiversity benefits, and have been observed to enhance property values.

Green roofs require maintenance. Expect to pay $1.00 to $1.30 per square foot in maintenance costs each year for the first two to five years as the plants become well established. Once established, maintenance and irrigation needs will decrease significantly.

Learn more about green roofs in Calgary.

Installed costs*

+260% compared to standard asphalt

Concrete tiles

Concrete tiles have good thermal properties when compared to other tile roofing; they reduce the amount of heat gained by the home from sun exposure without the need for additional insulation. This reduces the thermal load by as much as 45% when compared to asphalt shingles, reducing the need for as much attic insulation and ventilation.

  • Concrete tiles have a Class A fire rating, making them a good choice for homes in areas prone to wildfires.
  • In contrast to clay, concrete tiles are less prone to cracking from freezing and thawing cycles.
  • Concrete tiles are resistant to hail and high winds when installed correctly.
  • Concrete tiles are less water resistant than slate or clay.

Note: In some homes, concrete tiles may require the roof framing to first be reinforced to support the added weight.

Installed costs*

+265% compared to standard asphalt

Slate shingles

Because it is a natural stone, slate shingles are extremely long-lasting (anywhere from 70 to 200 years) and provide great protection against many climate hazards, including:

  • hail and wildfire;
  • extreme heat;
  • large tree branches and other debris from high wind events; and
  • shedding snow from a sloped roof.

The density of slate can help regulate the temperature in your home, providing protection from extreme heat and reducing energy consumption and costs.

Note: Slate is extremely heavy and can require additional structural support prior to installation. 

Installed costs*

+355% compared to standard asphalt

Clay tiles

Clay roof tiles are quite resilient but can be prone to damage from large hailstorms and suffer cracking from freezing and thawing cycles in colder climates.

Their resistance to high winds is largely determined by the fastening system; if installed correctly, the tiles should resist high winds.

Clay does a great job of blocking heat from the sun. Clay tiles are energy efficient, available in many types and colours and are also fire and water resistant.

Note: Like slate shingles, clay tiles are heavy and may require structural reinforcement of your roof prior to installation. 

Installed costs*

+370% compared to standard asphalt

What time of year to install a roof

Most roofing materials, and asphalt shingles in particular, should be installed in warmer months to ensure they adhere properly. Shingles installed during the cold months can be damaged or even blow off in moderate wind.

Did you know

Solar panels are made up of cells that collect energy from the sun and convert it into electricity that can be used to power your home. This helps to reduce greenhouse gas emissions that cause climate change. They are usually installed on the roof, above your current roofing materials.

Solar panels are built to withstand harsh weather conditions and are highly impact resistant, even when struck by hail. With an average of 2,396 hours of sunlight each year, Calgary is an ideal city for the use of solar energy!

Solar tiles, a relatively new technology, are like small solar panels. Rather than sitting on top of traditional roof tiles they are installed as part of the roof. Aesthetically, solar tiles are designed to blend in and look similar to a traditional roof. Visit calgary.ca/solar

Roof sheathing

Roof sheathing is the material (eg. plywood) that forms the bottom layer of your roof and provides a surface for water protecting membranes and roofing materials to be attached to. A roof that is sheathed completely will provide greater stability in severe wind and is better at handling the weight of a heavy snow fall.

To reduce the risk of damage to your roof associated with sheathing failure, consider choosing:

  • Fire rated sheathing material to bolster the fire resistance of the roof.
  • A thicker material (11.1 mm or 7/16” in lieu of 3/8” sheathing)
  • Longer nails (e.g., 2.5” rather than 2”) spaced closer together along both the edges of the sheathing panel and the interior supports (150 mm, rather than 300 mm).

If the sheathing is being replaced, you should also replace your roof underlayment while the area is exposed.

Roof underlayment

Roof underlayment is a membrane that goes over the roof sheathing. For increased resilience to climate hazards, consider:

  • Installing new roof underlayment when re-roofing your house.
  • Using two layers of underlayment that are cemented together, or an ice-and-water shield underlayment, for better protection from heavy rainfall and winter storms.
  • Using underlayment with a class A fire rating as a fire barrier.
  • The fire resistance rating of your shingles may depend on your underlayment.
  • Some shingle installations may require new underlayment, according to manufacturers’ instructions.
  • Reflective roof underlayment (or a radiant barrier) can be used to protect against extreme heat and reduce cooling costs; in colder climates it may be more cost-effective to increase your attic insulation.

Make sure underlayment is installed well in roof valleys, and around your chimney and other roof obstructions (skylights, dormers, etc.), where snow and ice can collect during the winter

Eavestroughs and downspouts

Eavestroughs and downspouts help protect your home from flooding and water damage and can help keep your building and building components (including the structure) dry; if your home does not currently have them, you should have them installed.

Recommendations for installing and maintaining eavestroughs and downspouts:

  • Eavestroughs and extensions should drain at least 1.2–1.8 metres (4–6 feet) away from your house. Direct the downspout extensions away from your home's foundation and your neighbour’s homes, onto a landscaped area of you yard where the water can soak into the ground.
  • Don’t connect eavestroughs extensions or downspouts to other pipes that drain directly onto a street, lane or sidewalk. Gravel and/or other debris can enter stormwater drains and/or water from eavestroughs or downspouts can cause gravel lanes to wash away, which may increase the chances of flooding in your community.
  • Don’t connect extensions from your eavestroughs to the sanitary sewer line or weeping tile. Excess water could overload pipes and cause flooding in your basement.
  • Clear leaves and other debris from your eavestroughs so that rainwater will not accumulate and seep into your basement.
  • Install a rain barrel to collect rainwater from your downspout, which can be used to water your lawn and garden. Make sure the rain barrel can safely overflow away from your home and your neighbours homes if you forget to drain it.

Extend downspouts a minimum of 4-6 feet (1.21-1.83 m) away from building to prevent recirculation of roof drainage at the foundation.

Disclaimer:  The content of the Climate Ready Home Guide is for informational purposes only and cannot be construed as technical advice with respect to any particular building(s) or construction project(s). The Climate Ready Home Guide does not recommend or endorse specific products or companies. All products and measures should be installed by a professional contractor, according to manufacturer specifications and following all City Bylaws and codes.

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