In our neighbourhood, the terms “west coast” and “wet coast” are interchangeable and commonly used to describe the climate where we live. While we are blessed with mild winters and moderate summers, the trade-off is months of rain–over a meter of water locally and up to five meters in some places nearby. For this reason, a good roof is (one that will stave off mold and keep things dry) is one of the most important parts of our building envelope.
When deciding what kind of roofing material to use, we wanted something that was green and durable, but also affordable and easy to install. Metal roofing was our first choice. Although not the cheapest option on the block, it’s cost has come down in recent years. Its many benefits also outweigh this up-front investment.
Some Benefits of Metal Roofing
Not only will metal roofing last more than 50 years (the paint is often under warranty for 40 years), it can also be recycled at the end of its life. In contrast, most asphalt shingles end up in the landfill after their average 17 year life span.
According to Alden Smith in his article, Roofing Materials – Asphalt versus Metal, “…the National Association of Homebuilders Research Center reports that 20 billion pounds of asphalt shingles are dumped into U.S. landfills every year. To put that in perspective, if you filled a 40,000 pound truck with the shingles dumped into landfills, each truck placed end to end would reach from New York to California and back, and then as far as Chicago.”
In addition, the metal roof helps complete a fire resistent envelope, which includes fiber cement siding, mineral wool exterior insulation, and metal soffits. This helps reduce insurance costs and improves the chance of our house surviving a forest fire in this rural area.
The steep metal roof will also shed snow well when we do get it. And though wind storms are very unlikely to damage our roof (no tornadoes or hurricanes here), shingles have been known to blow off. Additionally, when we harvest rainwater, the roof will be easier to keep clean and moss is less likely to grow on its surface.
During installation, we opted for Titanium underlayment (UDL) because it would be exposed for several weeks in wet weather before the metal roof was installed (otherwise we would have opted for the 30 lb felt). However, our Titanium UDL did not keep the roof sheathing or house framing dry as expected. This was possibly because an insufficient number of regular nails were used instead of cap nails placed on the marked locations. Also, the material was not taped to the Typar house wrap, so water ran along the wall behind it. The UDL also flapped around in the wind. If we ever build another house (we won’t, will we?), these are details we would correct.
Other Things to Consider When Installing Metal Roofing
Before the roofing began, our electrician put conduit through the roof for future photovoltaic wiring (and possibly solar hot water). If you are planning to add solar power to your new house, even down the road, the roofing stage is the time to do it. Our builder also recommended that the roofers install a ladder on the roof permanently to assist with chimney cleaning due to the steep pitch. However, we have not yet figured out how we will clean an 8′ tall metal chimney located mid-slope. (Any suggestions out there?)
Some people say that the roof defines the home. For us, a metal one is the choice that gives us the best value for our dollar and has less impact on the environment.