Westerleigh Retirement Residence
A half mile of continuous balconies at Westerleigh Retirement Residence wrap the south and west sides of all seven floors. Structural thermal breaks prevent cold exterior extensions of warm interior support structures from wasting heat, chilling interior floors and causing condensation that can encourage mould growth.
The Westerleigh Retirement Residence in Vancouver, BC
Isokorb® structural thermal breaks installed where continuous balconies penetrate the building envelope reduce heat loss by up to 90% at the penetration and up to 14% for the building overall, while increasing the warmth of adjacent interior floors by up to 27°F/15°C.
More than 100 of Westerleigh’s rental suites include balconies, which are thermally broken from interior support structures using Isokorb® structural thermal breaks. In addition to reducing heat loss and carbon emissions, they improve comfort for senior occupants by increasing interior floor temperatures.
The Westerleigh Retirement Residence in Vancouver, BC
Half Mile of Balconies Insulated With Structural Thermal Breaks at LEED Gold Retirement Residence
Developer-Owner builds for comfort, sustainability and return
Vancouver, British Columbia—Located in one of West Vancouver’s most exclusive communities, Pacific Arbour Retirement Communities’ (PARC) Westerleigh Retirement Residence sets new standards in senior living as well as sustainable design. The seven-story facility features a green roof with drought-tolerant vegetation, reduced use of potable water, innovative heat recovery strategies, and structural thermal breaks (STBs) as strategies that helped achieve LEED Gold certification.
“We own and maintain this facility, so we wanted it to be comfortable, sustainable and efficient,” explains PARC vice president of Development and Construction, Russell Hobbs.
The 140,000 sq ft (13,020 sq m) facility contains 129 rental suites, more than 100 of which access balconies that wrap around the south and west sides of all seven floors.
“The continuous six-foot-deep balconies wrap around the bottom four floors of the building and then step back on floors five through seven which are smaller,” explains project architect Shane Friars, principal at Besharat Friars Architects. In addition to providing amenity space, they shade the south and west sides of the building.”
To prevent the balconies from conducting heat from interior floor slabs into the exterior environment, they are thermally broken where they penetrate the building envelope using Isokorb® structural thermal breaks. "Without them, there would be quite a lot of exposed slab and thermal bridging,” Friars continues.
Structural Thermal Breaks insulate and support structural penetrations
Thermal bridging occurs where balconies, canopies, slab edges, parapets, rooftop equipment supports and other structures penetrate the building envelope. Like cooling fins, these penetrations draw heat from interior concrete and structural steel through the insulated building envelope, dissipating it into the exterior environment. In addition to wasting energy and emitting carbon, chilling the interior side of structural penetrations can cause condensation and mould to form on adjacent interior surfaces of today's air-tight, high-humidity buildings, exposing the developer to remediation and liability risk.
Tenant comfort is also compromised when uninsulated balconies chill interior floor slabs—an issue of particular significance in residences for seniors.
Isokorb® STBs for concrete construction create a thermal break between the interior slab and balcony. Stainless steel rebar projecting from one side of the STB is cast into the interior floor slab while stainless steel rebar projecting from the opposite side of the STB is cast into the cantilevered balcony, providing load-bearing support equivalent to that of monolithic balcony extensions of interior floor slabs.
Schöck North America claims that STBs reduce heat loss at balcony penetrations by up to 90 percent, and up to 14 percent for the building overall. At Westerleigh, some 900 STBs were installed. At 36 in. (914 mm) wide each, that makes for 2,700 ft (810 m), or more than a half of a mile of STBs, and a big factor in achieving LEED Gold, says Westerleigh Director of Construction, Bob Fritz.
“We had already cut our teeth on STBs from design to installation at our 11-story Cedar Springs Retirement Residence in North Vancouver,” adds Westerleigh chief engineer, Levi Stoelting, principal at Glotman Simpson. The projects had differences, however. The deep, continuous balconies at Westerleigh have a different loading configuration than for the eyebrows (smaller shade-producing concrete slabs) installed at Cedar Springs. Also at Westerleigh, “We had to figure out how to incorporate the modules into the fire separation and the cladding line and work those together with waterproofing and sound transmission elements. The product can accommodate this,” Stoelting says.
Architectural and engineering firms collaborate with STB supplier
“The STBs for Westerleigh were designed in conjunction with our structural engineer and architect,” says Russell Hobbs. “Because of the different loading configuration for the balconies, our engineers began working with Schöck eight months before construction to design the STBs specifically to the project.”
Based on the success with these two projects, PARC Living is installing STBs on its newest retirement residence in White Rock, BC, currently under construction.
One energy-saving strategy makes another possible
According to Project Building Envelope Consultant Sophie Mercier, Director of Building Science West at Morrison Hershfield engineers, structural thermal breaks also provided the flexibility to incorporate other energy saving measures. “With STBs improving the efficiency of the building envelope, you can use a smaller, less complicated mechanical heating system,” she explains. “For example, you can use electric baseboard heating, which gives you clean energy and a simple mechanical system. And simpler systems are less costly in the long term. That’s the benefit of having a thermally-efficient envelope.”
STB growth to accelerate with increasingly stringent codes
While the adoption of STBs throughout North America has been exponential since the completion of the Westerleigh project in 2013, it has also been largely discretionary. Canadian provinces and local jurisdictions, as in the United States, adopt the national building code on varying schedules, depending on local climatic, economic, cultural and political variables. Vancouver has adopted higher standards than in most U.S. and Canadian jurisdictions.
Increased exposure of STBs among developers, architects, engineers, governments and code officials charged with cutting energy use and carbon emissions may soon make STBs a code requirement, as it already is throughout Europe.
“People are seeing a better-performing building because of STBs, and they should become the industry standard,” adds Stoelting. “Their use is going to become more common because the code is driving us in that direction. We’ve used STBs on a mental health facility, a hospital, and a number of residential projects, and have recommended them on other projects that are in active design. STBs are a very good tool in our arsenal.”
Besharat Friars Architects
Ventana Construction Corporation