Achieving beauty and durability with continuous insulation

by arslan_ahmed | December 19, 2022 9:00 am

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By Karine Galla

Desirable esthetics for the exterior of any building are often tied to the project’s location, some buildings are background buildings, and some are built to be eye-catching. Some architects and building owners often rely on plaster to deliver traditional looks, and some find brick and wood to be more desirable and prevalent as the go-to material for a building’s facade.

The common denominator, regardless of geography, in today’s design paradigm is knowing one type of material is no longer good enough. Combining multiple esthetics is the standard rather than the exception. And since the days of monolithic design are long gone, architects are pushing the limits by integrating materials to create a modern, sophisticated look. At the same time, no designer can afford to sacrifice performance for an eye-catching look. Ever-evolving, stricter building codes, and heightened expectations from building owners now demand the right balance between beauty and durability.

How can designers, specifiers, and contractors capitalize on the growing trend of multiple esthetics for a building’s exterior while ensuring the structural stability of its enclosure?

The connective tissue to solve this equation lies beneath what the eye can see. It is a singular, cohesive building envelope which relies on exterior continuous insulation (ci)—more commonly known as a EIFS (exterior insulation finish system) in Canada. Employing materials to work in concert with each other can deliver key value propositions, such as design freedom, long-term performance, potential cost savings, and peace of mind.

The control layers of a building

As architects consider what the building will look like, they must also ensure it will protect its inhabitants and maintain its integrity over the life of the structure.

The control layers of a building’s exterior are built to repel natural forces such as rain, wind, heat, cold, ultraviolet (UV) rays, thermal movement, temperature changes, and remain intact for the life of the building. These control layers include:

• A vapour retarder to minimize condensation by controlling the flow of a water vapour as it shifts from high to low pressure areas.
• An air which reduces energy loss and condensation by limiting the uncontrolled flow of air through the wall assembly.
• A water penetration barrier to prevent water from damaging the building structure.
• A thermal barrier to mitigate energy loss designed to prevent thermal bridging.
• A durable and water-shedding facade to protect against environmental elements, impacts, UV exposure, pollutants, and more.
• A rain screen air pressurization layer, often located behind the water-shedding facade layer. Combined with a well installed air barrier, this helps prevent the capillary movement of water into a building.

The “pen test” can be applied to each control layer in the make-up of the exterior wall assembly. Each layer is assigned a colour code; for each layer, one line should be drawn which follows the layer across the detail of the wall assembly. Any time the pen lifts from the page, it highlights a loss of continuity. Any breaks in the air and moisture barrier can promote unwanted airflow, compromise in comfort for the people occupying the building, potential damage to materials from unwanted moisture build-up, and decreased energy efficiency.

Smartly engineered building enclosure systems contain all control layers in an integrated, tested assembly. When the first four layers, which are not visible, are planned as an integrated solution beneath the surface of the cladding, the individual layers work together to deliver a holistic approach. When acting as an integrated system, these four layers can also accommodate multiple facade options.

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Consider a building with concrete masonry units as a base, but then the sheathing transitions to glass-mat gypsum or plywood sheathing on the upper levels. Specifiers can select a single fluid-applied AWB for these different substrates, and they are also effective under multiple types of cladding, such as stucco, cement board, wood, vinyl, brick, stone, and metal panels. While the consistency of the fluid application may need to be adjusted, depending on the cladding above or below the substrate, a singular product as part of a tested system ensures greater reliability and less complexity. The fluid-applied AWB forms a bond with the wall sheathing and can act as a waterproof barrier when combined with a joint and rough opening treatment.

When it comes to the thermal barrier, EIFS systems on a building deliver the greatest R-value and overall energy performance. The American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) defines ci as “continuous across all structural members without thermal bridges other than fasteners and service openings.”¹

Thermally insulating the wall structure with EIFS wraps the building in a thick, well-insulated, and protective blanket. This eliminates thermal bridging, which keeps the wall structure warm and dry. Using the system on the outside of the wall maintains the temperature of the building wall structure above the dew point, effectively dealing with the potential for condensation caused by water vapour diffusion.

Advancements in material science now deliver thermal barriers for the exterior wall, providing even greater fire protection. Mineral wool insulation which is noncombustible, inorganic, and mould-retardant can resist fire and temperatures in excess of 1093 C (2000 F). When mineral wool serves as the thermal barrier in a fully engineered assembly, it also allows the vapour barrier to do its job without creating additional traps for moisture in the
wall cavity.

Extruded polystyrene (XPS is also commonly used with EIFS and provides a higher r-value per inch than mineral wool—5 vs 4.3—and has a higher compressive strength. However, while being vapour permeable, it has a much lower water vapour permeance rating, as per ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials.  It goes up to 1.5, while mineral wool can go up to 50 or higher. Choosing the right insulation will depend on the performance required by the designer.

Exterior facade cladding

Using EIFS on the wall assembly broadens the range of possibilities for the exterior facade cladding. Rather than being limited to delivering a textured, stucco-looking esthetic, architects and designers can paint with a broad brush. They can combine the traditional looks of brick, stone, concrete, and stucco with the modern appeal of metal, wood, and tile. For example, architects may choose to create the look of brick or wood over EIFS by employing resin-cast shapes. This approach maintains the timeless look of traditional brick or wood without having construction crews lay brick and mortar or cut and ship lumber. It creates an authentic-looking facade, capitalizing on the latest material science. Even the discerning eye has difficulty determining if the material used is not traditional brick or wood.

Resin-cast bricks and wood can be made to match traditional textures and colours while creating unique looks. Compared to their predecessors, resin-cast brick and wood require little maintenance. They will not warp, crack, or chip, and are not prone to efflorescence. For increased UV resistance and hydrophobicity, they can be enhanced with a wide variety of coatings as well.

The possibilities do not end with resin-cast shapes; architects can also achieve the look of brick, wood, concrete, stone, metal, and other materials using trowel-applied acrylic finishes or a variety of other exterior coatings. The result is a more durable surface delivering the desired esthetic.

Coating and finishes

Using an engineered building enclosure system for the exterior wall can also take advantage of the wide variety of coatings available to the architect, whether the cladding is made of metal, resin-cast shapes, or other materials. With today’s advancements, these coatings can deliver strong visual impact while improving the durability of the exterior wall.

For instance, certain finishes applied over the surface of the exterior cladding can dramatically improve the performance of the facade. Hydrophobic finishes repel water, keeping walls cleaner longer, and providing greater protection against algae and mildew without sacrificing design possibilities, while super-hydrophobic finishes have self-cleaning capabilities with superior algae and mildew resistance.

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Perhaps an architect seeks to achieve the look of a metallic panel without specifying metal for the cladding. Acrylic-based coatings can attain the look of metal in many colours and over smooth
or textured surfaces. The coating’s properties generate luminous depth and discernible visual impact, mimicking the properties of a metal panel but at a fraction of the cost.

Sustainability as a key factor

Achieving sustainability goals has become an integral part of any construction project. Engineered building enclosure systems utilizing EIFS provides several key advantages, such as sustainability.

Lighter-weight cladding (e.g. resin-cast brick versus traditional brick) allows lower deflection criteria and offers weight relief. This means the building requires fewer structural components, decreasing the amount of concrete or steel required in a building. This can also translate into cost savings and reduced embodied carbon for the building.

Construction projects also reduce their carbon footprint when they opt to ship lighter-weight cladding. Consider the savings of shipping traditional cubes of bricks, compared to boxes of resin-cast brick or pails of acrylic finish for exterior wall surfaces. It takes an equivalent of 15 trucks of traditional bricks to carry the same square footage as one truck of resin-cast bricks.

There is also a lower operational carbon footprint generated over the lifetime of the structure. Engineered building enclosure systems with EIFS produce a building which requires less energy for heating and cooling than uninsulated brick, stucco, or metal panels. Further, cladding systems with exterior insulation also use less energy over the full lifecycle of the building. This is driven by two key factors; EIFS delivers a higher total R-value, and proves to be more efficient than cavity wall insulation. The energy required to manufacture EIFS components is dramatically lower than masonry for instance, which requires kiln temperature up to 1800 C (3272 F). Depending on the finished used in EIFS, the acrylic finishes do not require any heating or cooling and the prefabricated finishes only need to be dried and cured at 60 C (140 F). The EIFS components are also light weight and therefore more can fit on a truck, lowering the carbon footprint.

According to an EIFS Council report, “Thermal and Whole Building Energy Performance of Exterior Insulated Finishing Systems Assemblies,” using EIFS can improve the performance of the building envelope up to 60 per cent, further reducing the energy consumption needed to heat or cool buildings.²

In addition, heavier cladding systems create more solid waste, both in production and at the end of their life cycle.

 Integrating components

With engineered building enclosure systems, the value proposition on the construction site is also a key factor. Crews install one single building enclosure behind the facade and there are no issues with transitions between insulation and materials. The single barrier system is put in place by one installer, simplifying the production schedule and eliminating the complications of using a different collection of components. Using one installer for all components can also translate to fewer errors and faster delivery of the finished product.

Engineered building enclosure systems integrate EIFS, an air and moisture barrier, a drainage plane, and a variety of textured finish options to create sustainable, high-performance wall cladding. The system improves indoor comfort and air quality while maintaining curb appeal and lowering lifecycle costs.

Additionally, the system approach reduces the complexity when it comes to compliance. Contractors and builders can rely on testing the system, rather than performing viability tests on individual components. This more readily ensures the safety of the building and its occupants, assuring all stakeholders in the value chain. From standards and codes for fire tests, to hurricane and wind impact tests, the system components are designed to work together for the optimal building envelope.

EIFS are fully tested and building code compliant assemblies, they are Canadian Construction Materials Centre (CCMC) listed. EIFS also meets National Building Code of Canada (NBC), fire resistance rating CAN/ULC S101-2013, Standard Methods of Fire Endurance Tests of Building Construction Materials, and CAN/ULC S134-92, Standard Method of Fire Test of Exterior Wall Assemblies, and its own standard CAN/ULC-S716.1:2019, Standard for Exterior Insulated and Finish Systems (EIFS) – Materials and Systems, within the Standard Council of Canada.

[4]B-Line Condominiums

For the development of the B-Line condominium in Toronto, there were three primary factors to be weighed and considered: the desire of client/developer Marco De Simone of Royalpark Homes for an EIFS (exterior insulation finish systems) solution, the need to accommodate a complex design with multiple finishes, and the tight, constricted job site.

To offer the condo residents premium comfort and maximum efficiency in the harsh Toronto climate, the developer viewed EIFS as essential. However, according to SkyRise Prefab’s vice president of business development, John Sopta, due to the site constraints, the only EIFS solution which could work for the project was a prefabricated panel.

“Site logistics make it impossible to do any sort of field-applied work there on the exterior envelope,” Sopta explained. “You cannot get in there with a baker’s scaffold; forget about setting up the requirements for doing other field-applied work.”

A prefabricated wall panel system was an easy choice from a site-logistics perspective, but there was still the question of esthetics because the building design called for multiple, disparate finishes. Using actual brick was a non-starter for the same reasons on-site exterior insulation and finish systems (EIFS) applications were out, as there was no room for scaffolding; but the manufacturer knew they had new finish layer options. These options, which could deliver on the design, included wood, resin-cast wood grain plank, brick, and a resin-cast brick. The immediate challenge was showcasing them for the client as the wood grain planks and bricks had just been introduced to the North American market, making this the first project to use them. “We took the client and the architect, from Romanov to sites all over the Netherlands and Germany,” says Joe Aprile, executive director at SkyRise Prefab. “They got to really appreciate what these products look like on buildings.”

The B-Line project was a challenging build in no uncertain terms. The manufacturer described it as the most complex project they had ever taken on, as the panels themselves were intricate, requiring elaborate prefabricated wall assemblies with two or three sections of walls, each with a distinct look, integrated into one. The design called for three finishes: metal, brick, and wood. The metal finish was accomplished with a customized finish surface which featured the look of limestone with a topcoat for a metal panel look. Brick and wood esthetics were created using the new products.

“The technology and the selection of materials allows us to do anything you want,” says Albert Bendersky, director of project management and construction at SkyRise Prefab. “The client can have any possible colour, any possible shape, and any possible texture for the exterior envelope.”

However, the real challenges came once the panels left manufacturer’s facility. The limitations, due to the small jobsite, made installation of the prefab EIFS panels difficult. “We were hoisting two- or three-storey high, sophisticated panels 3.6 m (13 ft) from electrical lines on one side, and 1.5 m (5 ft) to the left, there is a plaza,” explains Bendersky. “We had to use a tower crane, because there was zero distance between the building
and the neighbouring plaza.”

The team had a plan and they took the time to execute it, carefully and properly. By taking their time, they also saved time. What took them two months, Bendersky estimated would have taken a year using traditional methods, if it would have been possible at all. When everything is taken into account—the new customizable finish surfaces, the complex design, the small footprint of the jobsite—as the building stands and where it stands, there was no other way it could have been built. Ultimately, the project speaks for itself. “Every inch of that building is unique,” says Aprile.

The Parkview Senior Residence expansion in Newcastle used a high-performance wall system, with maximum protection from the elements. This system offers unprecedented design flexibility, which was achieved here using two prefabricated resin cast shapes and the manufacturer’s brick and wood.

Esthetics and high-performance

Building a facade with multiple esthetic elements is the new standard. The vision is made easier with EIFS. Architects can stretch their imagination, incorporating a wide palette of colours and textures to set the building apart, while delivering a high-performing structure which either meets or exceeds today’s building codes.

Reducing the number of trades and suppliers involved in the sourcing and installation of materials allows managers on a construction project to lower the budget using EIFS, and achieve greater efficiencies. This can lead to collapsed timelines, meaning the project will be delivered faster. Further, the potential for energy and cost savings improves the bottom line for all stakeholders and can help meet sustainability targets.

A building’s cladding is not a system by itself. While exterior cladding is critical to both the design and functionality, it is only one component of the building envelope.

It is important to look at all control layers as one symbiotic system—from what the eye can see to what is behind the outer wall—and recognize how this system drives greater energy performance, higher reliability, and the kind of curb appeal which sets a new standard in today’s design environment.

Notes

¹ Visit the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) to learn more, https://www.ashrae.org.[5]

² Read the Morrison Hershfield report, “Thermal and Whole Building Energy Performance of Exterior Insulated Finishing Systems Assemblies.” Visit http://eifscouncil.org/wp-content/uploads/2012/01/MH_EIFS_final_26May2014.pdf[6].

³ See Houston House on Sto Corp. https://www.stocorp.com/sto_project_gallery/houston-house[7].

⁴ Refer to 333 Grand St. at Sto Corp. https://www.stocorp.com/sto_project_gallery/333-grand-st[8].

[9]Author

Karine Galla is senior product manager for Sto Corp. She has more than 17 years of experience in product marketing in exterior insulation and finish systems (EIFS), stucco, air and moisture barriers, and other materials. Galla has a master’s degree from the University of Lyon, France. She is multilingual and holds the Association of the Wall and Ceiling Industry’s (AWCI’s) EIFS “Doing it Right and Building Envelope Doing it Right” certifications, as well as the International Organization for Standardization’s (ISO) internal lead auditor certification from Georgia Tech.

Source URL: https://www.constructioncanada.net/achieving-beauty-and-durability-with-continuous-insulation/

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