Over the past few weeks we’ve been asked the question “What is LEED®” when discussing the homes we are building in White Rock. In a nutshell, LEED® is the most stringent green home rating system in Canada/North America. In simple terms it is a bit like a building code, but of a much higher standard, requiring strict monitoring and documentation. The LEED® rating system take everything into consideration from the site selection & recycling of the existing house, right through to analyzing every screw, nail, material and mechanical system, that goes into the project. The projects are then rated using a points-based system to determine the final ranking. Certification can simply be “certified”, meaning the project met all the prerequisites, or can be one of the higher levels called “Silver”, “Gold” and the highest level, “Platinum”. For those who have been following the current project in White Rock, both homes have met all of the preliminary criteria to achieve a LEED® Platinum rating, something our team is very excited about.
So how does the LEED® rating system work? During the design phase, the independent LEED® rater produces a detailed energy model of the house in a computer, allowing them to estimate and analyze the energy usage of the prospective home, while providing the designer and architect with suggestions on ways that the design could improve. This system allows the design to be finely tuned for efficiency, long before the first drop of concrete is poured on the jobsite.
The LEED® system also considers many factors outside the home, things like irrigation and landscaping, plant species type, runoff mitigation, solar orientation and even proximity to shops, services and transit. The LEED® program takes a wide view of sustainable development, and approaches their ratings from a holistic point of view that goes well beyond the structure of the home.
The rating system also requires that every step of the project be documented, from “team meetings” amongst the principals, and background history / accountability documentation for all products and materials used in the home. Teams are asked to justify and explain their methodology and reasoning behind every design decision, thereby forcing dialogue and improving the final product. It is a far departure from the “old days” where the contractor stood on the jobsite with his level, and made many of the critical decisions “on the fly” while the home was being built.
Once the initial modeling and ratings have been completed, the LEED® raters check in on the build at regular strategic intervals. Much like a building inspector, they come to the site to view details and ensure that the original plans are being adhered to. They also produce a wealth of photo documentation throughout the build, used to verify the project at a later time. Once the project is virtually complete, the LEED® raters conduct blower-testing of the final product. This process is much as it sounds – they literally force air into the home and measure the leakage and air-tightness. After the blower door testing, and once construction is complete, the rater will return to the site yet again, and inspect the landscaping, irrigation and other exterior items to ensure that the original plan’s guidelines are met.
Then and only then, the house is given an official “Energuide” rating, much like an appliance would get. The enitre process, and every inch of the build is then complied and presented to the Canadian Green Building Council for their approval. The houses then become part of the permanent LEED® registry worldwide which maintains a database of the most sustainable building projects, both residential & commercial. Now say that 10 times fast.