Is your roof letting the weather in? Are the roofing shingles getting tattered? Is the exterior cladding of the house damaged or worn? Now is your opportunity to shop for durable products to improve the building envelope.
The best choices for exterior cladding and roofing lend themselves to different styles, require little maintenance and are sturdy and long-lasting, to reduce resource use. Renovating the building envelope also provides other solid benefits, like improving the thermal insulation and airtightness of the home and reducing the effects of thermal islands.
While this kind of renovation can add to the value of your home, it’s also a major investment. Careful planning based on a budget and well-defined needs is your key to success.
Construction codes and city planning rules provide guidelines for renovation projects, from safety rules to esthetic choices. Make sure your project follows these rules, or the municipality may demand that the new cladding be removed, generating needless waste.
Many municipalities regulate the use of exterior cladding materials for homes. For example, a certain percentage of brickwork may be required on the façade or on the entire building surface.
If you live in a heritage home, specific rules may apply to your entire renovation project or to certain aspects, such as the cornices.
Exterior cladding protects houses from weather and wind. The best choices from an environmental point of view reduce resource waste, by encouraging sustainable forestry, for example. Certain choices will also improve the energy efficiency of your home and allow you to achieve energy savings.
Wooden cladding has a lifespan of 30 years or more. It is very impact resistant, recyclable and it has a higher insulation value than most other choices. With exposure to the sun, the wood will discolour and turn grey over time. Choose wood from certified forests to support sustainable forestry and help reduce resource waste.
Pressed wood fibre cladding resembles the texture of wood, comes in a variety of colours and can be stained or painted. It often contains a high percentage of recycled content, which helps reduce resource waste. But these shingles are vulnerable to cracking and humidity. Their projected lifespan is around 25 years. Choose wood from certified forests to support sustainable forestry and help reduce resource waste.
Masonry – or bricks and blocks – is wear resistant and offers a very long lifespan compared to other products (over 100 years). These products may include recycled content (which is preferable), and they are recyclable or reusable. Their production is energy intensive and generates a lot of GHGs, but these impacts can be amortized over a long period when high-quality products are chosen. Since building masonry walls is complicated and the mortar can crumble if applied incorrectly, it is important to use the services of a specialist. Masonry is generally the most expensive option. In terms of energy efficiency, the low insulation value of masonry products is partly compensated for by their mass, which gives the structure greater thermal inertia and leads to fewer temperature variations inside the home.
Metallic cladding – generally aluminum extrusion or enamelled steel – has a long lifespan (40 years or more) and usually contains recycled content, as well as being recyclable. Steel is more impact resistant than aluminum, but neither has any insulation value. Compared to other materials, manufacturing metals requires a lot of energy and creates significant quantities of GHGs. Your best bet is to choose high-quality products that will last a long time to amortize their environmental impact.
Fibre cement cladding has a lifetime of over 40 years. It is easy to maintain and may be painted or stained. A coating must be applied to hide the joints. If you choose fibre cement, opt for products that contain supplementary cementing materials, which help reduce the GHG emissions associated with the production of Portland cement. These recovered industrial materials, which include fly ash (by-product of coal combustion) and silica fume (a waste product collected from furnaces used in the production of silicon alloys), increase the product quality.
Stucco (or acrylic coating) offers a 25-year lifespan and interesting insulating properties, but it is sensitive to temperature changes and structure shifts. For cement stucco, choose products that contain supplementary cementing materials, which help reduce the GHG emissions associated with the production of Portland cement. These recovered industrial materials, which include fly ash (by-product of coal combustion) and silica fume (a waste product collected from furnaces used in the production of silicon alloys), increase the product quality.
Vinyl is among the least costly cladding options and it features a long lifespan (40 years or more). Although it is made mainly with non-renewable resources, it may contain recycled materials and may provide some insulation value if it contains polyurethane. On the other hand, it may discolour, the joints are not airtight, and it’s vulnerable to impact and temperature changes. Use high-quality vinyl products to avoid premature replacement and the related resource waste. Reducing the use of vinyl products is better for human health, since vinyl can emit volatile organic compounds and other toxic pollutants during production, use, burial and in exposure to fire.
Solar energy is the most abundant source of renewable energy on earth. Producing and using renewable energy significantly reduces the environmental footprint of a home by reducing GHG emissions. Even though the acquisition and installation costs of these systems may be high for homeowners, the return over the long term must be taken into consideration.
The photovoltaic modules produce direct current (DC) electricity that must be converted to alternating current (AC) for residential use. It can be stored in batteries to maximize use. Installing panels and electrical components requires specific expertise, and homeowners should be well informed and clearly define their needs before beginning such a project. Installing photovoltaic modules is rarely cost-effective for a Canadian home and is generally insufficient to supply all of the needs of an average household. It can be used as a supplemental system to reduce dependence on public utilities (energy independence).
Thermal solar panels capture the heat of the sun and transfer it to a heat transport coolant to heat water in a water heater or in a pool. This is a more common solution in Canada. Thermal solar panels can reduce the energy needed to heat water by up to 60% (Natural Resources Canada), reducing GHG emissions.
Since medium and steep sloped roofs do not contribute substantially to thermal islands in summer, reducing environmental impact is mainly a matter of reducing resource waste by choosing quality wind-, ice- and weather-resistant products that will last for many years.
Shingles made of recycled plastics or recycled tires and hemp are now available on the market. They offer a good quality/price ratio and are generally guaranteed for 50 years. This type of cladding re-uses end-of-life plastics and tires, reducing resource waste.
Wooden roofing shingles have a lifespan of 30 years or longer. They’re more impact resistant, recyclable and they have greater insulating value than most other cladding choices. It is best to choose a quality product like Grade A cedar (superior quality, without knots or imperfections). This kind of wood is sufficiently moisture resistant to be installed on a roof. With exposure to the sun, the wood will discolour and turn grey over time. Choose wood from certified forests to support sustainable forestry and help reduce resource waste.
Metals such as steel and aluminum are recyclable and can contain up to 95% recycled materials. These features and their long lifespan (50 years or more) help reduce resource waste. Steel and some other metals are vulnerable to corrosion, though, especially when exposed to salty air. Choose ENERGY STAR® aluminum shingles over conventional products: by reflecting the heat of the sun in summer, they can reduce energy consumption for air-conditioning and cut down on GHG emissions.
Cement tiles have a very long life (50 years or more) and they can be recycled as aggregate at the end of life. They are resistant to weather, acid rain and fire. Producing these products requires a lot of energy, though, and generates a lot of GHGs. It’s best to choose products that contain recycled materials and supplementary cementing material to reduce the GHG emissions associated with the production of Portland cement. Cement tiles are costly and the roof structure often has to be reinforced to support the additional weight.
Asphalt shingles are easily accessible and inexpensive, and they come in a wide variety of colours. Since their lifespan can vary from 15 to 30 years, it is important to select the product that offers the best possible quality, to avoid early replacement and reduce the waste of this non-renewable resource.
Flat and low-pitched roofs contribute to the creation of thermal islands in summer, due to the black or dark surfaces that absorb the energy of the sun. These localized hothouse effects increase the surrounding air temperature by several degrees. Simply installing light colured or white roofing materials can reduce the effects on human health and save energy on air-conditioning, reducing GHG emissions.
Well-installed green roofs are a very eco-responsible solution because they reduce impact to human health by reducing the effect of thermal islands. They also encourage biodiversity, reduce water runoff pollution and improve roof insulation, cutting energy consumption for heat and air-conditioning. But the structure of existing houses usually has to be significantly reinforced to support the additional weight, which could lead to high costs. These roofs require regular maintenance and sometimes irrigation.
Elastomeric membranes are asphalt membranes combined with elastomer (flexible polymer). Their lifespan is approximately 21 years in Canada: good quality products that are well installed can last longer. Choose white membranes: they reduce thermal islands and the heat transferred to the building in summer, which allows you to save energy on air-conditioning.
Multilayer asphalt membranes are composed of several layers of felt saturated with bitumen, with the top layer covered with gravel. They are economical and widely used, but less ecological than other alternatives because they are made with non-renewable resources and are not recyclable. Their lifespan (average of 15 to 20 years) depends on the quality of the installation. Use white gravel rather than grey, to reduce the effect of thermal islands and the amount of heat transferred to the attic in summer.
The protection provided by a green roof increases the roof’s life expectancy to 30 or 40 years from the average of 15 to 20 years.
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