Canadian Architect

Feature

Green Roofing: A Bird’s Eye View

Roofing manufacturers offer a panoramic range of environmentally-sound products for residential application.

October 1, 2001
by Nyla Matuk

When the shingles start to blow off or the membrane begins to buckle and crack, it’s time to re-roof. These days, there is plenty of opportunity to go green. Wouldn’t we all rest easier knowing that the roof over our heads was not only beautiful and durable, but also ecologically sound? The roofing industry has finally made such assurances possible and affordable. Numerous roofing products manufactured from recycled materials vie for your specification dollar, and appeal to architects’ and clients’ increasing demand for green building materials. Here’s a roundup.

Asphalt

The bulk of expenditure on re-roofing steep-slope roofs is still spent on asphalt shingles, despite what the Environmental Building News Product Directory and Guideline Specifications describe as poor durability and non-recyclable characteristics. In the United States alone almost 30 billion lbs of asphalt shingles are dumped into landfill every year. An alternative to conventional asphalt shingles is available from Ondura Corporation, which produces shingles that are 50% asphalt and 50% cellulose fibre from 100% post-consumer mixed paper wastes. The product comes in sheets and tiles and is described as safe for rainwater collection systems.

Rubber and Plastic

Recycled synthetic roofing shingles that look like slate or cedar help retain vernacular regional style or historical integrity. Made of recycled rubber or plastic, they offer alternatives to high-end cedar shingles and shakes, natural slate, clay or concrete. Invented in Canada, Starloy is a material made from synthetic rubber and recycled industrial plastic from manufacturers of car hose, shoes, tires and other rubber products. Majestic slate by EcoStar, Inc. is a quarter of the weight of slate and comes in rectangle, beaver-tail and scalloped styles. It is made from 100% recycled content. EcoStar also distributes Euro-Bati’s EuroSLATE, containing 60% recycled content. It is even lighter than Majestic and has the square look of European slate.

For more Canadian content, look into the MooRoof by Moore Enviro Systems Inc. of Squamish, British Columbia. The MooRoof is a shingle made of used tires which can be installed with concave or convex (tread showing) sides facing up. These bullet-proof roofs have a 50-year warranty and good sound absorption.

Crowe Building Products Ltd. of Hamilton, Ontario, produces the Authentic Original, the first recycled plastic and rubber slate product in North America made with 100% recycled materials. The company’s Authentic 2000 line–which comes in mitered-edge and beaver styles–uses thermoplastic olefin (TPO) which, according to Crowe, is a structurally stronger synthetic rubber than the ubiquitous ethylene propylene diene monomer (EPDM) and the preferred, more “virginal” product of the automotive and household goods industry suppliers. The durability of the synthetic slate is another attractive feature, with guarantees of 40 to 50 years for most products.

Wood and Plastic

Using 100% recycled woods and plastic, the Eco-Shake shingle by Re-New Wood, Incorporated is designed to reduce the amount of manufacturing materials that end up in a landfill and uses only waste wood products. To replicate a weathered shake roof, Eco-Shakes are available in four standard colours, with custom colours also available. The installed product has passed a 110 mph wind-driven rain test from Florida’s Dade County. It requires no maintenance and comes with a transferable 50-year warranty.

Fibre-Cement

Guaranteed for 50 years and chosen by environmentally-conscious designers for their durability, shingles made of fibre-cement materials may nonetheless use wood from distant countries. Although they no longer contain asbestos, as was once the case, there is still the question of embodied energy related to their Portland cement content. They may be of concern in Canadian installations because of potential problems with freeze-thaw cycling should water penetration occur. The use of polymer in the manufacturing process minimizes the likelihood of water- absorption problems, and can be found in FireFree shingles from American Roofing Materials of Portland, Oregon. The FireFree line includes products like the Rustic Shake and the Quarry Slate shingles, formed into a wood shake or a slate look-alike, respectively.

Slate

Natural slate roofing is an excellent product from an environmental standpoint because it is almost free of processed material and offers terrific durability. Slate can last 70-100 years without maintenance and may be reused for new building. Durable Slate Co. stocks salvaged slate and clay tiles and can match colours that are no longer available. TileSearch, Inc. at www.tilesearch.net is a search service for salvaged slate and tile.

Metal

Metal shingles are typically made from high-content recycled structural steel and cast iron. They can be applied over existing asphalt, saving the cost of tear-off and dumping into ever-growing landfills. It is important to avoid using different metals for roofing, flashing and fasteners because of the potential for galvanic corrosion when exposed to water.

Metal roofs provide a slide-off surface for accumulated snow, preventing damage from the formation of ice dams. Aston Wood Steel Shingles by MetalWorks are made from as much as 50% recycled material consisting of G90 galvanized steel with a Kynar 500 or Hynar 5000 coating. The wood shingle look-alike is available in five colours. Even greener, Zappone shingles are made from either 85% recycled copper (75% post-consumer) or 100% post-consumer recycled aluminium. They have a polyester/ceramic finish that comes in eight colours and the company offers recycled aluminium fasteners and accessories as well. The familiar pistachio-green oxidation will be fully realized 11 years from the time the reddish copper roof is installed.

Wood

While traditionally wood shingles were cut from old-growth western red cedar, it is no longer sustainable to harvest from such forests. Industries Maibec, Inc. of Sainte-Foy, Qubec, makes shingles from eastern white cedar. The trees, under the chain-of-custody certification jointly held with the Seven Islands Land Company, are from strictly managed forests certified by the Forest Stewardship Council. Eastern white cedar shingles come in natural, kol-dried, factory-stained gray or beige, are treated with an oil finish.

With a new generation of roofing options, where green is concerned it appears that the sky’s the limit.



Print this page

Related Posts







Have your say:

Your email address will not be published. Required fields are marked *

*