Residential Showcase Utilizes Sto Ventec Glass Facade

Architect's stunning new home in Virginia is the first to incorporate Sto Ventec exterior glass panels.

StoVentec Glass facades have been widely used in Europe for years, and are just now being introduced in the U.S. The product works well as both an external rainscreen cladding system, and as an internal decorative option.

StoVentec Glass is an advanced ventilated rainscreen cladding system consisting of a glass-faced composite panel, thermal insulation, and sub-construction. The result is an engineered, high performance façade with a sleek, elegant look.

Architect Jeff Davenport, a principal at Perkins & Will, chose such a StoVentec Glass panel system for his private residence on Lake Anna in Louisa County, Virginia. It is the first such installation in the country, and based on the stunning results, will most certainly generate future use of this versatile, highly functional product.

The contemporary plan initially called for metal panels, but the contractor on the project, Pillar Construction, suggested StoVentec Glass panels, which would provide better insulation and incredible aesthetics.  In addition to the advanced rain screen cladding with a back-ventilated system and air cavities for drainage, StoVentec Glass panels also offer thermal and sound insulation.

Opaque glass panels wrap around the entire entertainment, fireplace area as well as the garage façade.

Part of the Ventec manufacturing process includes the fusion of color onto the back of the glass. The color melts into the glass, creating permanent colored glass panels that will not wear, scratch, fade or incur water damage. Vivid colors and different panel size options are available, offering many aesthetic choices for either new-build or renovation, which you can learn about here.


Mineral Wool For Building Exteriors

Mineral wool insulated exteriors offer tremendous performance as well as a wide range of aesthetics.

Sto Product Manager Karine Galla recently penned a piece in Construction Specifier on mineral wool as an option to enhance the thermal performance of continuous insulation on a building’s exterior.  While mineral wool has been around for over a century, the article provides an overview on how the insulation is produced today and outlines its many attributes for exterior facades.

Mineral wool is typically made from a combination of melted volcanic rock and steel slag spun into a mass of fine, intertwined fibers. These fibers conduct heat very well, but when pressed into rolls and sheets they create an excellent insulator. In addition to its thermal performance, mineral wool also appeals to designers and specifiers because of its fire resistance. Since mineral wool insulations are naturally noncombustible, they will not burn or release harmful smoke and hot gases.

Mineral wool is also vapor permeable, with a vapor rating of up to 50. This means water vapor can readily diffuse throughout the material; it will not retain water. Since most mineral wool products are made from more than 50% post-industrial recycled content, and contribute so significantly to energy conservation, they are also considered very “sustainable”.

As a result of these performance virtues, mineral wool is increasingly used in building exteriors. Especially when builders are looking to mitigate fire risk, noise intrusion, and energy waste, as well as ensuring moisture control in an “all-in-one-solution”.

Mineral wool insulation has been widely used in industrial settings such as petroleum refineries and power plants, as well as for lofts, cavity walls, flat roofs and heating systems. It has also been used as an insulation layer behind various claddings such as curtain walls, rainscreen facades and exterior insulation and finish systems (EIFS).

While suggesting that mineral wool products warrant consideration, Galla also outlines some of the product’s challenges and important factors to consider in designing a wall assembly with mineral wool insulation. These include: air and moisture control, detailing solutions at the joints and seams, making wind load calculations, ensuring fastener longevity, and determining impact resistance.


Winter is Here & StoPanel Can Help

StoPanel installation can save valuable time and money, especially in the winter months.

As inclement weather descends upon construction projects across the country, now is a good time to remember the incredible value of prefabricated, insulated exterior wall systems by Sto.

Because panel manufacturing is done off-site and indoors, there are fewer weather delays.  Because the time to install a panel system is far less than a conventional building envelope, it enables builders to better weather the winter months and make the most of their construction calendar.

Regardless of the weather, prefabricated wall systems can compress a construction schedule, and make for a faster build time.  In addition to saving time, lightweight, continuous insulation StoPanels can also save money.

There are countless testimonials and examples of how StoPanels have saved on construction costs and greatly reduced the time of building envelope installation.


STO Product Featured in Multi-Family Passive House

Passivehaus certification ensures a minimum of 90% in energy savings.

LUCHA, a leading affordable housing developer in Chicago, has just built the first multi-family Passive House in the state of Illinois. The landmark project in the Humboldt Park neighborhood has been certified by PHIUS — the Passivehaus Institute organization in the U.S. – with a projected energy savings of 90% over conventional construction.

The first multi-family Passive House in Chicago. Photo: Gordon Walek

The Passivhaus Institut was established in Germany in 1996, to promote design, construction and insulation practices that make a building envelope more energy efficient and resilient. The goal was to construct walls and windows that are airtight – keeping warm air inside during the winter and cool air contained during the summer.

In addition to an energy efficient building envelope, a “Passivehaus” building also incorporates advanced cooling and heating systems as part of the design. It encourages balanced heat- and moisture-recovery ventilation as well as solar utilization. While advanced technologies, appliances and systems such as climate-controlled zone programming are important for energy conservation, most building professionals agree that the building shell is the most critical component in achieving a zero-energy design.

The Passivehaus organizations in the U.S. and in Germany both work to educate contractors and property developers about the PH standard and train companies on how to measure and certify buildings.

Certification Process

While there are differences between the U.S. Green Building Council (USGBC), LEED (Leadership in Energy and Environmental Design) certification and PHIUS certification, the programs are aligned to encourage high energy-efficient performance in the built environment. Passive House certification also sets air quality and health standards and requires additional testing to ensure the standards are met. According to many industry experts, when it comes to green building and energy conservation, Passive House certification is rigorous, but the resulting construction delivers absolutely superior energy efficiency.

The Passive House project in Chicago was designed by Landon Bone Baker, and the six-unit multi-family residence, is part of LUCHA’s Tierra Linda Project which will include other affordable housing units in the area. To capture energy efficiencies and ensure an effective air and moisture barrier, the contractor and architect for the Passive House complex chose StoTherm® ci with StoColor® Lotusan® for the building’s exterior cladding. Having worked with Sto in the past, they knew the Sto products would ensure they received the coveted PHIUS certification.

The StoTherm® ci system integrates continuous insulation (ci) with air/moisture barriers and drainage, offering a wide range of textured finish options to create an aesthetically pleasing, sustainable wall cladding. This high-performance system not only saves energy but improves indoor comfort and air quality while maintaining maximum curb appeal and lowering overall life-cycle costs.

StoColor® Lotusan® exterior coating was chosen due to its water- and dirt-repelling characteristics, and self-cleaning qualities derived from the organic structure of the lotus leaf.  Sto Lotusan® enhances an exterior’s resistance to mold, mildew and algae with high water vapor permeability, and lowers maintenance costs by extending cleaning and re-coating cycles. Available in any color within the extensive StoColor System, Lotusan is UV-stable with excellent color retention.

With Sto’s advanced building science and materials, LUCHA was able to secure the PHIUS energy-efficiency rating. They also created a multi-family complex with pleasing aesthetics that is impervious to the extreme weather conditions of the region.

It is estimated that there are now more than 60,000 passive-house certified buildings worldwide with nearly 500 in Germany, and more elsewhere in Europe. And while there are only 46 PHIUS certified buildings in the U.S. today, there is a rising level of interest (especially in residential construction) in major metropolitan areas such as Chicago and New York.

LUCHA is to be applauded for the organization’s commitment to Passive House building and the Tierra Linda project – a sustainably-oriented development that brings affordable housing with green technology to low-income residents of Chicago.  In addition to improved heating and cooling efficiency – improving occupant comfort — this commitment will also help decrease energy costs for renters.


The Cavity Wall Conundrum

Complex, modern building designs require balancing the need to keep the building dry, airtight, thermally efficient, and code compliant. Photo © Vladimir Sazonov Shutterstock.com

A new e-book called the “Evolution of Building Enclosures”, published by Construction Specifier, offers a four-part series, including an article on what the magazine calls “the cavity wall conundrum”. Authored by Todd Skopic, a building science manager, the article provides an in-depth, technical look at the use of open-joint rain screens coupled with unconventional wall orientations. While these configurations can be appealing, they also pose a potentially dangerous combination; abating water ingress is an important issue to address, but these systems must be compliant with building codes, including those that test for combustibility.

Balancing the need to keep the building dry, airtight, thermally efficient, and code compliant can create what Skopic calls a cavity wall conundrum. As more architectural firms push the limits of building design, ensuring a safe and efficient building envelope is becoming more complex. The growing practice of combining open-joint rain screens with unconventional wall orientations, such as a backward-sloping configuration, offers a prime example.

In such structures, design teams want to prevent water ingress, but they also need to follow the latest building codes. Staying compliant with certain ones, such as the energy code, complicates matters by introducing certain materials that increase potential safety risks.

Managing water with building enclosures involves the three Ds: deflection, drainage, and drying. Open-joint rain screen systems offer an increasingly popular means to achieve the three Ds and behind every open-joint rain screen, is an air and moisture barrier to defend against water ingress. All of these solutions are subject to and must comply with an abundance of codes and regulations.

The 2012 International Building Code (IBC) requires buildings in Climate Zones 4 to 7 to have a continuous air barrier, which in most cases also takes the form of a water-resistive barrier. The 2012 International Energy Conservation Code (IECC), is also driving the use of continuous insulation (ci), which in some cases is combustible. It needs to comply with the National Fire Protection Association (NFPA) 285 – a standard fire-test method for evaluating the fire propagation characteristics of exterior, non-loadbearing wall assemblies containing combustible components.

In other words, today’s design teams are trying to design building envelopes that are watertight, airtight, thermally efficient to meet code requirements, and to be NFPA 285-compliant. Solving this ‘cavity wall conundrum’ is possible, but it requires some familiarity with the competing design challenges and different industry standards.

This in-depth, technical article discusses rain screen design, and the standards for managing air and water, in context of the codes for continuous insulation (ci), air barriers, and water-resistive barriers, as well as life safety issues related to combustibility. For instance, how do cladding attachments impact a system? What is the the value of a continuous insulation system with adhesive-backed sheet membrane that isn’t penetrated? What are the differences between sprayed polyurethane foam (SPF) and expanded polystyrene (EPS) when used as insulation in cavity wall assemblies, vis a vis thermoplastic extruded polystyrene (XPS) which is a thermoplastic foam rigid insulation board? And how do these compare with mineral wool or fire-enhanced polyisocyanurate (polyiso) mineral wool in performance and code compliance? And what are all the codes?

Solving the Conundrum

Building designers are increasingly aware of the competing requirements and standards involved in modern cavity wall design. They should know continuous air barriers and insulation systems, along with NFPA 285 code and other compliance issues, which must be balanced with the goal of keeping water out of a building. Achieving this balance will help designers create the safest, most effective building envelope possible and thus solve the cavity wall conundrum. And on the building materials front, manufacturers need to test all their products to ensure they meet the extensive industry standards and testing.

The other chapters in the new e-book cover the benefits of specifying complete masonry veneer wall systems, defining and testing construction tape and flashing durability, and moisture in new concrete roof decks.