Archetype Sustainable House: Green today, green tomorrow

by / Jessica Krippendorf

Production builders and homeowners are the target audience for Toronto and Region Conservation Authority's LEED Platinum Archetype Sustainable House, set to open in November at the Kortright Centre for environmental education just north of Toronto.

The 4100 sq. ft., semi-detached house offers the flexibility to showcase a continuum of green technologies - House A features some that the average homeowner could implement immediately in renovations or new builds; technologies that are more sophisticated or still in testing were used in House B. Overall, the project represents an educational experience for home builders, home owners and visitors to the Kortright Centre.

TRCA wanted the project to showcase affordability for the home owner and still meet a minimum requirement of LEED Gold. Appeal for production builders was also a key component, as TRCA hopes the project will influence the thousands of houses being built around the GTA.

Alex Waters, manager at the Kortright Centre, says 85,000 students from kindergarten to post-secondary participate annually in the Kortright Centre's 50 environmental programs. Archetype Sustainable House will be the first stop in a tour of Kortright's Energy Program.

"That program begins with steps you can take toward energy conservation and reducing the carbon footprint of a building. Archetype will be part of delivering that first message people get before the program moves on to exhibiting technologies and techniques that can further reduce the impact a building has on the environment, including demonstrations of wind turbines, solar wind energy, solar panels and others."

Development of the project has been a collaborative effort from the beginning. TRCA hosted a project design competition three years ago, which was independently administered by the Design Exchange. Seventeen designs were submitted and an architectural trio called Building Blocks was awarded the contract. Building Blocks' principals - Anne Stevens, Fort Architect Inc., Clelia Iori, Iori Architects Inc. and Terrell Wong, Stone's Throw Design Inc. - engaged in an integrated design process with designers, engineers and students to fine-tune the project's ultimate design.

Building Block's modular system, which allows the design to be panelized, with each floor having three blocks or modules to choose from, allows for cost mitigation and personalization of the homes. Each of the blocks offer three options, as does the garage. "The outside footprint stays the same but the inside can host a variety of changes," says Waters.

"The houses as we've built them are custom, but if you were to put the concept into a sub division the cost would come in at about $100 per square foot. Also, a builder would go through it with a fine tooth comb and the cost would come down quite dramatically."

House A is 1800 sq. ft.; House B is 2300 sq. ft. Both use the Advanced Framing Technique with 24-inch on-centres and Forest Stewardship Council (FSC) certified wood. All jack studs are eliminated in both houses, as are lintels, which are built into the headers. I-joists are used in the floors, and attic trusses are replaced with a beam and structural insulation panel (SIP) system, ensuring the attic space meets the homes' criteria of being flexible enough to accommodate a growing family.

A single layer of 1/2-inch synthetic gypsum from CGC, Inc. covers non-load-bearing interior walls; a double layer of 5/8-inch Type X was used on the firewall. Nancy McPherson, architectural products specialist for CGC and chair of the technical education committee for CAGBC, says CGC's synthetic gypsum was the best choice for the project because it contains 98 percent recycled material and meets LEED's distance requirement of 800 km or less between the manufacturer and building site. CGC also donated drywall tape and its Dust Control drywall compound, which improves indoor air quality during construction.

Being a key component in any green building, insulation in the home is heavy and thorough. House A has two inches of Styrofoam under the floor for an R10 rating. The basement walls are constructed with an ICF-like product, which comprises of waste wood and concrete, formed into blocks and filled with concrete. Two inches of high-density FlexiBatt Roxul insulation line the inside walls, achieving an R20 rating in combination with two inches of Styrofoam on the outside. The walls above ground carry six inches of Roxul (R22) and three inches of EPS on the outside for a combined R-value of 32. The renovation-ready attic features R40 SIPs from Insulspan provided through Kent Trusses.

Roxul insulation, containing 40 percent recycled content, was a natural fit for the project, says product manager in Roxul's marketing department for residential products, Mark Bromily. "It's a dense insulation and has a snug fit so there's no transfer of energy between the inside and the outside wall environments. It's also manufactured less than 30 minutes from the building site, so that makes it an environmentally-friendly choice too."

While House A features more affordable and practical options, House B is more elegant, says Waters, "with a double height living space and master bedroom with sitting room and en-suite in the attic." It has the same foundation as House A. Its first floor has six inches of Icynene spray foam (R22) and three inches of Styrofoam on the outside, adding up to an R-value of 32.

The second and third floors are insulated with Heatlok Soya, a polyurethane insulation made of 30 percent recycled plastic and one percent soya. The walls are six inches, but only four inches are needed to achieve an R22, and with three inches of EPS on the outside the result is an R32.

For demonstration purposes, each house has two heating systems: one electric and one gas. The project's HVAC Committee was tasked with researching the best in heating systems and presenting the findings to the rest of the organization. The resulting list of 17 systems was given to students at Ryerson University who placed the data in a matrix that allowed TRCA to profile each system according to isolated criteria such as GHG emissions, up-front cost, life cycle or a host of others.

House A's electric system is a Hallowell all-climate, air-source heat pump, and a solar-assisted Vessimann mini boiler that runs on gas. Waters says air-source heat pumps were popular ten years ago, but phased out because they didn't heat below freezing. "This one can heat below -20 and still provides savings on electricity while also providing air conditioning."

The heating systems in House B are an electric ground source heat pump and a combined heat and power furnace that uses Stirling Engine to generate electricity and recover the wasted heat to heat the home.

Ryerson University partnered with TRCA to monitor the technology in both houses for three years.

The project began July 8 and completion is set for November 12. Approximately 700 volunteers and tradespeople sponsored by their companies worked on the project in waves, resulting in 75 percent of the labour being donated. Sixty percent of the building materials were donated by over a hundred manufacturers. Sponsorship and volunteer recruitment were organized through the Toronto GTA Building Industry and Land Development Association (BILD), which partnered with TRCA from the beginning. It was a logical alliance, says Waters, as BILD is exactly the audience Archetype Sustainable House is meant to influence. BILD promoted the house to its 1800 members, which greatly assisted in the project's development.

"People have really engaged and are pleased to be part of it," says Waters. "It's an educational process for them too, so we take the time to tell them why things are done a certain way and they've given us some really good practical advice. Everyone has learned from this project."

"A lot of good things will come of this. We're not expecting builders to take on everything we've suggested, but if some of it can be applied to new builds or renovations, that's a great start."

The objective to reach builders has already begun, says Waters, describing how TRCA was able to engage builders working on a new sub division across from the project's building site. "The end result was that the municipality offered the builder an incentive to build 1600 EnergyStar homes."

Learn more about Archetype Sustainable House at <www.sustainablehouse.ca>.

awaters@trca.on.ca