Sustainable cladding choice equates to high-performance building envelopes

by Katie Daniel | January 18, 2016 4:43 pm

By Amanda Sinnige and Kevin Day
Exterior insulation and finish systems (EIFS) are in an ideal position to respond to the requirements of many of the sustainability programs becoming more prevalent in society. Indeed, there are specific features of these cladding assemblies that add to the value proposition in terms of sustainable construction. (This article’s co-author also explored EIFS’ long-term sustainability in the January 2015 issue of Construction Canada. “Exploring EIFS’ Long-term Sustainability,” by Kevin Day and Daniel Schlegel, can be read online here. [1]The feature outlined the history of these assemblies, their adoption of drainage and secondary moisture control, and the small ecological footprint compared to many other cladding materials).

Sustainable aspects
To expand on the features of EIFS being a part of sustainable construction, one should consider the numerous variables related to the building lifecycle.

Long-term durability
The longer a cladding can last, the fewer resources are necessary to maintain the building’s service life. EIFS have a life expectancy of 50 years or more. (“Exterior Insulation Finish Systems: Designing EIFS (Clad Walls) for a Predictable Service Life,” by co-author Day (while at Morrison Hershfield) was part of the Proceeding of the Eighth Conference on Building Science and Technology, February 2001). Not only does the cladding have inherent long-term durability, but the continuous insulation (ci) also results in a reduction of potential condensation problems, as can happen with the thermal bridging intrinsic of other cladding systems. This also reduces the likelihood of maintenance or repair required to rectify condensation problems.

Energy efficiency
The building performance for space heating and cooling significantly improves with the use of EIFS as the cladding choice. In new construction, the most recent building and energy codes are becoming more demanding in terms of thermal performance. EIFS offer an easy solution to meet these requirements. In terms of retrofits, the assembly provides solutions to improve the energy performance of uninsulated or under-insulated buildings. The ci inherent in EIFS virtually eliminates thermal bridging, increasing the energy-related performance of the building.

Additionally, the thickness of insulation can be adjusted according to specified requirements, including where more aggressive energy efficiency is required (such as may be the case for a Leadership in Energy and Environmental Design [LEED] Platinum building). This adjustment can significantly reduce the need for heating and cooling, therefore, minimizing energy use.

Reuse
EIFS can be used to rehabilitate existing buildings clad with other materials without having to remove and dispose of the original cladding (i.e. no waste, no recycling, and no landfill usage).

When necessary, components of the system can be recycled. For example, the expanded polystyrene (EPS) insulation can be separated and ground down to become filler in recycled content EPS, or filler in soil to promote stabilization. Lamina and mesh coatings can be separated and ground down to promote stabilization in soil, or used as filler in geotechnical applications.

EIFS components are chemically inert and will not harm the environment when they are disposed.

Resource conservation
Due to their lightweight nature compared to other cladding systems, such as brick or tilt-up concrete, EIFS do not impose a significant dead load on the building structure, allowing for significant savings in structural materials.

Considering the “value proposition”
Renowned building scientist Ted Kesik’s white paper, “The Value Proposition of EIFS,” outlines all the performance characteristics of a wall, and evaluates EIFS’ performance in each of the categories. (“The Value Proposition of EIFS” was published by the University of Toronto in April 2012). It is interesting to note EIFS, as a cladding, can achieve all these requirements (provided there is a structurally sound substrate). Kesik rated the performance of EIFS strongly in all 11 categories except for fire resistance, durability, and questionably esthetics. However, EIFS perform well when designed as part of a high-performance building envelope.

1. A system that will meet the requirements of Canadian Construction Materials Centre (CCMC) and/or CAN ULC S716.1, Standard for Exterior Insulation Finish Systems (EIFS)–Materials and Systems, should be specified. This standard deals with the full breadth of exposure parameters, such as:

• sunlight/ultraviolet (UV);
• salt (maritime);
• high humidity (mildew resistance);
• rain;
• tensile bond;
• moisture management; and
• hygrothermal durability.

2. Fire resistance can be validated by meeting the applicable building code requirements for protection of foam plastics. On lot lines where unprotected openings are limited to 10 per cent or less, non-combustible insulation is likely required (i.e. semi-rigid mineral fibre).

3. Impact resistance can be augmented with the proper design, supply, and quality control of the reinforcing mesh, to minimize nuisance impact damage.

4. The assembly’s esthetics can be maintained by eliminating impact damage, keeping lightly reinforced systems away from pedestrian and maintenance contact, and increasing reinforcement. The placement of finish coats can also affect the ‘look’ of the systems. It is important the placement of finish coats respect exposure conditions by selecting appropriate colours for the climate conditions (e.g. hot pink in a maritime climate is not recommended), ensuring all rainwater is designed to deflect away from the wall, at parapets, roof/wall intersections, balconies, and window heads and sills, and avoiding placement of finishes at soft grading, landscaping, and garden planters (or else select colours/textures not affected by these conditions).

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.

Programs supporting the sustainability of buildings
There are many programs supporting the renovation and retrofit of buildings, the construction of new buildings, and the improved sustainability for a city or district as a whole. EIFS have many features that can contribute to the success and goals of these programs.

EIFS can contribute to a well-insulated building, thereby improving energy efficiency. Additionally, the assemblies are durable, contribute toward resource conservation, and are made of reusable, chemically inert materials. Each program may have a different focus for sustainability, but in each case EIFS can contribute to the improved performance of the buildings. A brief description of a few of these programs highlights the impact EIFS can have on these goals.

Toronto 2030 District
Sponsored by Building Owners and Managers Association (BOMA) Toronto, the Ontario Association of Architects (OAA), and Sustainable Buildings Canada (SBC), the Toronto 2030 District aims to support key stakeholders with the goal of improving the performance of all buildings, both new and existing, as related to energy performance and sustainability.

Toronto 2030 District endorses the principles of the 2030 Challenge—an international endeavour endorsed by Architecture Canada—proposing targets for energy consumption of new buildings reducing fossil fuel consumption by 100 per cent by 2030, and interim goals of 80 per cent reduction by 2020 and 90 per cent reduction by 2025.

The role of EIFS in this scenario could be significant, given consideration to the aforementioned “Tower Renewal Guidelines.”

LEED
According to the Canada Green Building Council (CaGBC), “buildings generate up to 35 per cent of all greenhouse gases (GHGs), 35 per cent of landfill waste comes from construction and demolition activities, and 70 per cent of municipal water is consumed in and around buildings.” It is clear making buildings greener can have a significant impact on larger environmental goals.

As a building rating system, LEED considers and encourages the adoption of energy-efficient construction and sustainability, along with considerations for community design, water resources, and indoor air quality (IAQ). EIFS play a vital role in energy performance and resource conservation and can help in obtaining a LEED designation or certification.

Energy Star
Energy Star Homes [2]is another product in the portfolio of Energy Star products. The goal is for these homes to operate using approximately 20 per cent less energy than a home built to code. Homeowners who choose Energy Star homes are typically looking for “a new home that is energy-efficient and environmentally friendly.”

These homes incorporate rated energy-efficient appliances, lighting, windows, doors, and mechanical equipment. The increased insulation of walls and ceilings beyond code requirements is also a key feature of Energy Star homes. EIFS with ci is an easy solution to help reach these goals.

BOMA Best
BOMA Canada’s BOMA Best[3] program assesses and certifies existing commercial buildings with regard to their environmental performance. This program encourages the adoption of energy-efficient retrofits in part by reporting the results. As discussed, EIFS is a tool that can easily assist in achieving energy-efficiency goals as well as improve the appearance and performance of existing claddings.

Conclusion
Contemporary designers that understand the value proposition of EIFS will be successful in creating high-performance buildings, with sustainable low-carbon, and low-energy intensity materials.

As renowned building envelope expert, John Straube, states in his book, High-performance Building Enclosures:

exterior insulation finish systems, when using a drainage gap and air-water control membrane, are a practical implementation of the perfect wall. (The book was published by Building Science Press in 2012.

When considering sustainability features and esthetic versatility, exterior insulation finish systems can be a way to improve durability in our cities.

Amanda Sinnige is the Manager of Technical Services for Dryvit Systems Canada having joined the company in early 2015. She has worked in the field of building science for the past 25 years, concentrating her efforts on the energy performance of buildings, sustainable construction and renewable energy and the impact of these on the performance of the building envelope. Sinnige can be reached at ajsinnige@dryvit.ca.[4]

 

Kevin Day is the director of sales and marketing for Dryvit Systems Canada, and a LEED AP. He is the vice-chair (and past-president) of the Exterior Insulation and Finish Systems (EIFS) Council of Canada, and a past-president of the Ontario Building Envelope Council (OBEC), winning its 2014 Anthony A. Woods Award. Day is regarded as a leading expert on EIFS, and is widely recognized for his extensive cladding engineering experience. He is a past contributor to Construction Canada. Day can be reached at kcday@dryvit.ca[5].

Source URL: https://www.constructioncanada.net/sustainable-cladding-choice-equates-to-high-performance-building-envelopes/

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