July 10, 2006

CONCERT PROPERTIES LTD.

The 28-storey Jazz tower in downtown Toronto is among the first residential highrises to feature a green roof.

Highrise tower residents gain green roof benefits

Heritage façades, energy efficiency add value for buyers, developers

DON PROCTER

correspondent

A $45-million residential highrise tower nearing completion in downtown Toronto meets sustainable building principles by featuring a green roof, incorporating three heritage facades and meeting high energy performance standards.

The 28-storey Jazz tower, a development by B.C.-based Concert Properties Ltd., is one of the first residential highrises in Toronto to feature a green roof.

Twelve types of pre-cultivated sedum cover about 200 square metres of the seventh floor podium roof, says Sibylle von Knobloch of Nak Design Group, the development’s landscape architect.

The plants are rooted in a one-inch deep vegetation blanket. Underneath is a felt layer which retains moisture, minimizing watering needs. Such green roofs are typically installed directly over the roof’s insulation layer with gravel spread over the sedum plants or sedum can be added over the gravel ballast layer.

The roof system was supplied and installed by Xero Flor Canada Ltd., the Canadian office of Germany’s Wolfgang Behrens Systems Development.

A pioneer in green roof development, the company has designed sustainable roof gardens throughout Europe for the past 35 years.

Xero Flor president Joy Schmidt calls the Jazz project an “extensive green roof”, meaning it requires little maintenance. The alternative, an “intensive green roof”, is maintenance-intensive.

While extensive green roofs cost more than conventional roofs, they provide sun and weather protection for the roofing membrane, which can significantly increase its lifespan, says Schmidt.

“If your membrane’s life-span is 10 years, it might last 20 or even 30 years with a green roof.”

The 28-storey tower, at Church and Shuter streets, was designed by architect Burka Varacalli in conjunction with heritage consultant E.R.A. Architects.

E.R.A. integrated the heritage facade of the 115-year-old former Athenaeum Club/Labourers’ Temple facade, and replicated two adjacent historic facades into the tower’s podium.

Mario Cimicata, senior project manager of Deltera Construction Ltd., general contractor for the project, says before the rear of the Athenaeum Club could be demolished, steel shoring was installed to the full height behind the facade. Extensive remedial work was required on the foundation, bricks and existing windows.

“The demolition had to be done by hand, a very slow and tedious procedure,” says Cimicata.

The facades of the two adjacent historic buildings were in poor condition so rather than restore them in-situ, they were disassembled, catalogued and reassembled and/or replicated by Clifford Restoration Ltd.

Sam Trigila, of Clifford Restoration, says it is usually easier to disassemble a facade and restore it off-site then work in-situ.

It is also more economical because shoring a facade can add 30-50 per cent to a contract price tag.

To replicate the two facades, Clifford started by taking a series of photographs and creating detailed measured drawings of the buildings in-situ.

A complex cataloguing process was developed by the company to ensure that every element disassembled — right down to the individual bricks — would go back in the right place, he says.

All the building elements were cleaned, restored or replicated if beyond repair.

The original single pane windows were restored, but with thermopane glass.

Trigila sees more facade restoration work in Toronto than he did 10-20 years ago. While facadism increases overall construction costs, owners often see a quick payback because they can charge higher lease and rental rates on a new building with historic features.

The tower was one of Deltera’s more difficult challenges, in part because of the large seven-storey podium that features recreational facilities and 22-32 suites per floor.

While the windows in the heritage facades dictated the placement of floor plates, resulting in “very unique residential units”, it created additional challenges for the building team.

For example, says Cimicata, flyforms couldn’t be used; everything was done with knockdown forms.

“It was all handwork. There was very little repetition in construction. Interior courtyards from the second to the fifth floor also created atypical floor plates.”

Jazz meets high energy efficiency standards through enhanced exterior wall insulation and high-efficiency boilers with variable speed motors that provide hot water heat on demand. Occupancy lighting sensors are installed in common areas such as the parking garage.

“We evaluated the building from an energy perspective against LEED criteria and found it would have been pretty close to a silver,” points out Brian McCauley, senior vice-president of Concert Properties. Concert owns the project in conjunction with OMERS (Ontario Municipal Employees Retirement System).

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