Building Envelope Systems Architecture
What goes into designing building envelope systems? A cursory glance may answer the question – foundation, walls, windows, roof. However, each component must resist environmental elements such as temperature fluctuations and heat loss, weather, and fire. Additionally, modern building envelope architecture products are expected to be sustainable and reduce carbon emissions.
The building envelope forms the thermal barrier between the interior and exterior environment. With envelope technologies accounting for approximately 30% of the primary energy consumed in residential and commercial buildings, building envelope architecture plays a key role in determining levels of comfort, natural lighting, ventilation, and how much energy is required to heat and cool a building.¹
Components of Building Envelope Architecture
The wall assembly has evolved over the years. In conjunction with insulation, walls need to minimize energy losses, resist moisture and weather, and reduce noise.
Each year, about 1.5 quads of energy is lost through walls in commercial buildings in America.²
Today, the rainscreen system is the wall assembly standard. Rainscreen systems create airspace behind a building’s siding or exterior finish. This airspace creates a protective exterior barrier that manages moisture and provides energy-efficient performance through continuous insulation (ci) and reduced thermal bridging. Each component of the rainscreen works together to achieve efficiencies and ensure the longevity of the building.
Rainscreen Façades
Building envelope wall façades
are the major components of the building envelope. More than decorative, rainscreen façades are the first line of defense against the elements. Architects and contractors consider low moisture absorption, impact strength, industry-leading warranties, color and design options, and cost among other factors when selecting rainscreen panels.
Not all rainscreen façade panels are created equal, however. Petrarch Composite Stone Rainscreen Panels and Steni Composite Stone Rainscreen Panels out-perform other cladding options.
Read Rainscreen FAQ →
Continuous insulation (CI) eliminates thermal bridging and reduces building costs and energy loss. When metal is used to connect exterior components of a building directly to the interior framing, a thermal bridge is formed. A thermal bridge allows thermal energy to enter or escape. This creates a vulnerability in a building for hot or cold spots.
Since 2012, the International Energy Conservation Code (IECC) has required continuous insulation (CI) in the building envelope. The 2012 IECC prescribes how much insulation is required for each of the 8 U.S. climate zones, for various types of above-grade walls, below-grade walls, roofs, and floors.
The most efficient CI systems create an air barrier by sealing the building envelope. By preventing energy from escaping or entering through the structural walls of a building, CI systems can increase the building’s overall thermal performance.
Building envelope consultants recommend high-performing CI systems such as ArmorWall Plus (shown.) ArmorWall Plus is a fire-rated structural insulated sheathing. In addition to being fire-resistant, it provides a proprietary air and water-resistive barrier. Rainscreen cladding frames can be attached directly to the ArmorWall Plus panels.
According to the Department of Energy:
In 2010, conduction through windows in the commercial building sector accounted for 1.60 quads of lost energy used for space heating, but offset cooling loads by 0.3 quads. Additionally, solar heat gain through windows accounted for 1.38 quads of energy lost from space cooling, but offset heating loads by 0.97 quads. Recent advances in window technologies, for both reductions in conduction losses and solar gains, can help with tremendous energy savings in commercial buildings.¹
There are two metrics in the window industry used to measure heat flow and efficiency:
- U-value
- R-value
The R-value is a measure of heat resistance and is an assessment of material effectiveness. The U-value measures heat transfer (loss or gain) through the actual glass. U-value does not rate the specific material as the R-value does. Rather, U-value is a calculation of the conduction properties of various materials that make up the window. The aim is high R-value and a low U-value.
Consult a building envelope consultant for more information.
Solar Roofing and Arrays
In 2020, 43% of all new electric capacity added to the grid came from solar, the largest such share in history and the second year in a row that solar added the most generating capacity to the grid. Solar’s increasing competitiveness against other technologies has allowed it to quickly increase its share of total U.S. electrical generation – from just 0.1% in 2010 to over 3% today.¹
The move to commercial solar addresses rising greenhouse gas emissions by buildings. Developers of new projects are being tasked with choosing products that support green building initiatives. As solar prices have fallen and options for investing in clean energy have expanded, the number of commercial solar installations has grown rapidly across the country. Commercial rooftop systems, solar parking canopies supporting a corporate headquarters, large off-site installations powering data centers, are a few applications of commercial solar.²
The south-east-facing façade and roof of Powerhouse Telemark will generate 256 000 kWh each year, approximately twenty times the annual energy use of an average Norwegian household, and surplus energy will be sold back to the energy grid.
Green Roofing
Sika® recently launched a Green Roofing System. Among other benefits, green roofing results in a reduction in energy consumption. Green roofs can reduce peak energy demand by lowering a building’s heating and cooling costs. No matter what the design, vegetated roofs offer many social, environmental, and economic benefits.
