Figure 1 lists the requirements of a wall as identified by Kesik, along with EIFS’ solutions as they pertain to sustainability.
Research concerning the sustainability of buildings
There is an ever-growing need and interest to improve sustainability in our society. This affects both new construction and existing buildings and communities. Significant research has been conducted evaluating sustainability issues and methods improving performance. One study, “Tower Renewal Guidelines,” is of particular interest with respect to sustainability in Canadian cities. It provides guidelines on renovating and renewing the life of the staggering number of under-performing apartment buildings.
Its report states, “more Canadians per-capita live in high-rise dwellings than their American cousins.”4 In the Greater Toronto Area and Hamilton (GTAH), there were more than 1000 towers built between 1960 and 1980 now in need of a retrofit. This resource outlines many retrofit strategies, with overcladding identified as one of the most effective due to the reduction/elimination of thermal bridging, which is of particular concern with these buildings.
Other important studies include one by the U.S. National Institute for Standards and Technology (NIST) wherein it calculated the total carbon footprint of EIFS. The material measured about 1686 g of CO2/unit of cladding as compared to brick at 8303 g CO2/unit, and stucco, aluminum, cedar siding, and vinyl averaging 4614 g CO2/unit. This analysis was recognized in NIST’s Building for Environmental and Economic Sustainability (BEES) 4.0e (2007) software.
A case study prepared by an architectural firm in the United States, compared EIFS cladding to traditional brick, precast concrete panel, and stone exterior veneers. The study examined the impact of these claddings on the requirements for steel framing, footings, HVAC, and construction time using a theoretical three-storey, 4907-m2 (52,820-sf) steel-frame office building in the south-central United States. Although climate conditions are different than in Canada, the results of this analysis are worth noting.
EIFS with 50 mm (2 in.) of EPS was compared with a combination of brick, limestone, and precast concrete—all other wall elements were the same. A total construction cost saving, calculated at $570,200, was due to the reduction of footing size and steel requirements, the replacement of stone, brick, and precast concrete cladding with EIFS, and a reduction in cooling tonnage. More specifically, 14.25 tonnes of steel, 5443 kg (12,000 lb) of exterior metal studs, and 85 m3 (112 cy) of concrete would be saved by reducing the footing size. This study shows EIFS contribute to sustainable construction in ways that are not immediately obvious. Additionally, it is estimated the total mechanical peak load would be significantly reduced by approximately 62 per cent.
A case study developed following the recladding of an occupied apartment building in Guelph, Ont., dealt with a deteriorating exterior (Figure 2). (“Tower Renewal Guidelines for the Comprehensive Retrofit of Multi-unit Residential Buildings in Cold Climates” by Ted Kesik and Ivan Saleff of the University of Toronto, 2009). Due to years of moisture penetration, the exterior concrete masonry unit (CMU) and steel elements of the building needed replacement. EIFS was chosen to re-clad the building because of the complexity of the details required, and the versatility of EIFS. The outcome of this renovation includes:
- repair and preservation of existing cladding prior to EIFS application;
- elimination of water intrusion thereby increasing the longevity of the building;
- improved appearance; and
- a 20 per cent reduction with respect to electrical-based heating consumption.
These retrofits were all implemented while residents were still living in the building, illustrating the sustainable advantages of EIFS in a retrofit situation.
