Building Envelope Renovations To Enhance Sustainability

Consider these green building strategies, inside and out, when planning facility upgrades.

By Mark Hanson, Ph.D., LEED AP and Amy Moore
From the October 2018 Issue

Have you ever attended an event in a building from 301 A.D.? The Etchmiadzin Cathedral in Vagharshapat, Armenia, considered to be the oldest cathedral in the world, has continued to serve people for hundreds of years. And although people think of sustainable, green building for new, modern structures, this ancient cathedral is the epitome of green building. Built using local materials, operating with little or no energy bills, and having a life cycle cost that can be spread across centuries, it is an extreme example of how existing structures can be sustainable.

green building
The Etchmiadzin Cathedral in Armenia, built 301 A.D. is an ancient example of a “green building.” (Photo: Areg Amirkhanian via Wikipedia)

While modern green building methods continue to add innovative science, engineering, materials, and technology to new buildings, these same developments can be applied to existing buildings as these are maintained and renovated. Accumulated knowledge, along with lessons learned from ancient and more recent buildings, can guide work toward sustainability in new construction as well as existing facilities.

Buildings use approximately 40% of all energy consumed in the U.S. and are major contributors to greenhouse gases. As the 2030 Challenge works toward carbon-neutral buildings by 2030, owners and managers of existing buildings can do their part through green remodeling. The 2030 Challenge is an effort initiated by Architecture 2030 and supported by the AIA (American Institute of Architects) and other professional organizations to achieve zero carbon in the operation of new buildings by the year 2030. More than 400 firms have committed to the interim and final goals.

Despite the ever-increasing body of knowledge, practices, and applications, the basic approach to a green building is simple:

  • Provide building spaces that meet occupants’ needs.
  • Surround those spaces with high quality shells made from responsibly sourced materials that provide thermal and moisture management, good indoor air quality, durability, daylight, and outside views.
  • Provide high-performance systems for conditioned air, artificial light, water and wastewater conveyance, and, possibly, on-site solar energy.
  • Enable occupants to readily operate and maintain their facilities.
  • Do all the above at a competitive initial cost and reduced operating costs.

Facility managers contemplating building upgrades should consider these principles as they determine goals for sustainability, simplified maintenance, and operational cost savings. And this includes weighing upfront costs against life cycle costs to determine affordability. As illustrated with the Etchmiadzin Cathedral in Armenia, a building’s useful life can spread initial investments across many generations or even centuries. A long lasting building reduces future renovation needs and demolition waste, and a building that people find comfortable, useful, and beautiful increases pride in that building which, in turn, increases the likelihood that it will be well-maintained.

As facility managers prioritize goals, they should determine which measures will contribute most toward their goals. These can include improvements to the building shell and upgrading interior systems.

Green Building Envelope

The building envelope, including foundation, walls, and roof, will be the most visible and longest-lived part of a building. A high-performance shell provides energy efficiency, protection from wind and moisture, occupant comfort, durability, and aesthetic beauty.

As part of the building envelope, exterior walls must control water and air infiltration, vapor transmission, and thermal bridging. New 2015 building codes, adopted in Wisconsin as of May 1, 2018, require continuous insulation in new construction as well as in renovations where greater than 50% of the building is modified. Rigid foam and other insulation applied to the entire exterior of the building just under the façade material can help prevent the thermal bridging allowed by insulation between studs that conduct cold through walls. Continuous insulation also helps prevent air infiltration and vapor transmission. By preventing moisture vapor from condensing on the inside of sheathing, continuous insulation reduces the chance of mold and improves indoor air quality. It also makes a building quieter and more comfortable.

While increased wall insulation is desirable, applying insulation in retrofit situations can be challenging and costly. An alternative improvement—and the first of three keys to cost-effective renovation—may be roof replacement, if needed. This can provide many green opportunities. Adding insulation during roof replacement is accomplished more easily than adding wall insulation and can have a higher ROI. Installing a high-reflectance, white membrane can reduce heat island effects in urban areas where an abundance of black roofs contributes to increased summertime peak energy demands. Reduced temperatures around rooftop equipment such as air handling units and chillers decreases energy costs in any setting.

Similarly, installing a green vegetative roof can reduce heating and cooling costs and air pollution, provide rooftop gardens and valuable green spaces in urban settings, and improve views for those in adjacent taller structures. In healthcare settings, views of nature provided by green roofs can help promote healing and faster recovery. Roofs can also provide valuable space for solar installations.

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The Holy Wisdom Monastery in Madison, WI, used significant roof space to add solar PV systems for its energy use. (Photo: Hoffman Planning, Design & Construction, Inc.)

Holy Wisdom Monastery in Madison, WI included three green roof improvements during the 2009 construction of a new monastery and renovations to a 1960s-era building and during a 2014 solar addition. The Benedictine sisters there had a 125 kW on-site solar PV system installed on a white EPDM roof. In a different roof section over the 1960s building, they added insulation and a green roof creating a walkable garden. This project earned a LEED Platinum rating from the U.S. Green Building Council.

The second key to a cost-effective renovation is window replacement to improve energy performance, building aesthetics, and occupant comfort and to provide views and daylight. The Appleton Area School District in Wisconsin recognized this and decided to replace windows that radiated cold, lost energy, allowed unwanted solar heat gain, and produced uncomfortable glare. New, low-E glass windows reduced heat loss, and lower visual light transmittance helped manage glare and unwanted solar heat gain and reduced the need for window shades, thus preserving views and daylight.

Inside A Green Building Renovation

Inside the building, the third key to an effective renovation is upgrading lighting, HVAC, plumbing, and IT. These must be integrated with the building envelope to create a system of parts that work together toward lesser energy and water use, better indoor air quality, and increased thermal comfort.

A surprising number of mechanical systems in existing buildings are not operating near their original intent. A common deficiency is insufficient outside air caused by incorrect settings in the building control system and parts of the mechanical system that are not operating. Code requirements typically require correction of these problems during major remodeling. In addition to the renovation itself, monitoring is critical to ensuring green building benefits are being achieved. Many monitoring systems are available to track monthly utility bills for electricity, natural gas and water, monthly production of on-site solar, and peak demand levels in kW.

Facility managers are finding many ways to green their facilities through renovation. Existing buildings can be renovated to be sustainable, which helps to prolong their useful life while reducing negative impact on the environment. Those managing these types of project can take cues from ancient structures while looking to the future.

green buildingHanson is director of sustainable services at Hoffman Planning, Design & Construction, Inc., headquartered in Appleton, WI. He is a LEED AP with a doctorate degree in environmental studies. Before joining Hoffman, Hanson served as the Executive Director of the Energy Center of Wisconsin.

green buildingMoore is a designer with Hoffman Planning, Design & Construction, Inc. A LEED Green Associate, she is a graduate of the University of Wisconsin-Madison with a bachelor of science in interior design. Her 25+ years of experience in the design and construction profession includes owning an interior design firm.

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