Sustainable Historic Preservation  

by the WBDG Historic Preservation Subcommittee

Updated: 
10-13-2016

Introduction

Preservation maximizes the use of existing materials and infrastructure, reduces waste, and preserves the historic character of older towns and cities. The energy embedded in an existing building can be significant  of the embedded energy of maintenance and operations for the entire life of the building. Sustainability begins with preservation. A recent report The Greenest Building: Quantifying the Value of Building Reuse (2011)  delved into the question of how green an existing building truly is. The Preservation Green Lab, a part of the National Trust for Historic Preservation, with the assistance of building constructors, sustainability consultants and life cycle analysts, established a set of case studies of recognizable building types; both renovated existing and new construction, in order to quantify the benefits of building reuse against that of new construction.

Recent advances in life cycle analysis (LCA) typically used in product design, are expanding into building/construction materials allowing the team to review new construction energy impacts. With some exception, comparing similar uses, types and locations, the existing buildings reduce climate impact over the newly built. Additionally, the findings suggest that even sustainably-constructed new built structures do not recoup energy outlays for approximately 30 years when measured against a renovated existing building. While more development is needed to mature the LCA approach, the Lab's conclusion was direct: reusing older buildings result in immediate and lasting environmental benefits.

LEED Silver Rated Balfour-Guthrie Building, Portland, Oregon

LEED® Silver Rated Balfour—Guthrie Building, Portland, Oregon

Historic buildings were traditionally designed with many sustainable features that responded to climate and site. When effectively restored and reused, these features can bring about substantial energy savings. Taking into account historic buildings' original climatic adaptations, today's sustainable technology can supplement inherent sustainable features without compromising unique historic character.

Preservation keeps our nation's history and culture alive and we learn much from the methods and practices of those who came before us.With our threatened environment, it is imperative that we make sustainable living a part of our lives.The public benefits of both preservation and sustainability are very clear and there is no reason why these goals cannot work together.Revising the current version of LEED® to better account for the social values and environmental benefits of preserving historic structures is a good start.The discussion, however, must continue to engage the preservation, sustainability, and construction communities to assure the best possible outcome.

Description

Preserving a building is often called the ultimate recycling project, yet preservationists commonly fight the stigma that historic buildings are inefficient and require daunting corrective measures to retrofit for energy saving devices and systems.Green and sustainable design has become an increasingly popular issue in both the preservation and new construction industries.Preservation and green goals overlap, and reconciling their differences is possible, provided that both sides strive to be as creative and flexible as possible.

The development of the International Green Construction Code (IgCC) by the International Code Council (ICC) is intended to become a new overlay standard to encourage the integration of sustainable design into new construction. The IgCC also provides provisions for existing buildings and existing building sites to incorporate sustainable design practices.This overlay code allows for local jurisdictions to tailor, through adopting electives, suitable options that address local and regional sustainability goals. Green building rating systems continue to grow in importance and prominence and have expanded to include existing buildings over the years. The USGBC's LEED rating system, the Living Future Institute's Living Building Challenge, Green Globes, the International Well Building Institute's WELL Standard, or the Sustainable Sites Initiative SITES may all play a role in a project or be required. So be sure to check for the latest requirements to determine how best to implement them to an existing historic building or historic architectural work.

The LEED® for Neighborhood Development Rating System (LEED®-ND) integrates the principles of smart growth, new urbanism, and green building into the first national system for smart, green, and healthy neighborhood design.LEED®-ND also addresses historic buildings.

The U.S. Green Building Council's LEED®O+M is a guideline for greening Existing Buildings. While this is a valuable checklist for maximizing the sustainable qualities of existing buildings in a real estate portfolio, it stops short of addressing historic buildings specifically. This page provides guidance for meeting LEED® and similar sustainability standards in historic building projects. Within the five LEED® categories, the following issues require special attention:

Sustainable Sites

Heat Island Reduction

Before the mid-20th century, most parking areas were pervious surfaces often surrounded by trees and covered with gravel to minimize mud problems. Specify low albedo porous paving, such as masonry pavers, reduce heat island effects and create the added benefit of controlling storm water runoff. Where treatment of run-off water is required provide an impervious barrier below a pervious surface to direct runoff to an oil-water separator and/or a treatment facility.

Green Roof atop the Heinz 57 Center, the former Gimbel's department store building
Aerial view of green roof atop the Heinz 57 Center

Heinz 57 Center, the former Gimbel's department store building; green roof.
Photo courtesy of Pennsylvania State Historic Preservation Office

Water Efficiency

Reducing water use can negatively impact historic plantings and landscape features. Preserve historic plantings and landscape features by balancing the water goals within the building and site.

Exterior photo of 18th century brick country estate, Working Horse Farm, located in Virginia
Manicured landscaping featuring a base and statue in a clearing surrounded by hedges on a Virginia Country estate

Working Horse Farm, parts of which date from the 18th century, Fauquier County, Virgina. Restricting water usage too greatly could irreparably damage the surrounding landscaping of this Virginia Country estate. The cultural landscape is an integral part of the historic setting, which must be respected.

Water Use Reduction

Historically, water conservation was a part of daily life. Cisterns collected rainwater and water was reused. Modern gray water recycling systems have evolved from these traditional water conservation methods. Specify low flow toilets and water conserving fixtures or consider options that are similar to historic water conservation methods.

"Cultural landscapes" often play central roles in the overall makeup or character of historic properties.They also need water to survive. Therefore, like historic structures, they must be cared for and respected, even historic plantings that may not be native species.Efficient irrigation systems may be used to save water, and recycled 'gray' or rainwater may be captured for use in gardens and surrounding landscapes. But restricting water for irrigation to achieve the percentage savings required by LEED® may irreparably change the important relationship between a building and its surrounding landscape. Unfortunately, currently there are no provisions within LEED® for exempting cultural heritage areas from these calculations.

A bio-swale, or depression in the earth, created to redirect rainwater away from the storm sewer system with a large house in the background
A rain barrel placed discreetly behind a historic house

Former maternity hospital, Minneapolis, Minnesota. This "bio-swale," or depression in the earth, was created to redirect rainwater away from the storm sewer system.Water entering this area is filtered and the natural process of absorption and evaporation begins. A "rain garden" is a more formal version of a bio-swale with the same desired effect. These sustainable features are appropriate provided they are sensitively sited; historic landscapes are not altered for their installation; there are no concerns regarding archeologicalresources; and they are designed in a manner consistent with the character of the site—for example, a formal rain garden planted with flowers would not generally be appropriate at an industrial site.
Photo courtesy of the National Park Service

This rain barrel is placed discreetly behind a historic house and has very limited visibility except from the rear of the property.
Photo courtesy of Audrey Tepper

Energy and Atmosphere

Green buildings address energy and atmosphere issues through strategies that reduce the amount of energy required, and by using more benign or renewable forms of energy. Suggestions on approaches to the specific LEED credits within this category are discussed below.

Minimum Energy Performance

  • Working historic shutters can reduce heat gain significantly. Closing shutters in the morning and opening them in the late afternoon controls heat gain during warm months.In cold months, following the opposite pattern reduces heat loss. This is particularly effective when a building has significant thermal mass.
Brick building with Pepsi log painted on the side and solar panel system visible on the back of the roof
View of a brick building from the back parking lot with a Pepsi logo painted on the side of the building and a highly visible solar panel system on the roof

Highly visible solar panels can have an adverse impact on both the historic building and the surrounding historic district.
Photos courtesy of the National Park Service

  • Awnings, where historically appropriate, are efficient, and work with the seasonal path of the sun. Properly designed awnings can reduce heat gain by 65% and more.

2 photots: on left is an old photograph of a firehouse with a giant awning, tractors parked out front, and men posing for the picture in Pilot Point, Texas, 1906; on the right is he front/top floor view of an ornate historic building with a 'stair step' top, and stone awning-like structures above the top widows. The words Central Belting Hose and Rubber are still visible around the main eyebrow window which along with side windows still have louvers in place.

Firehouse showing the use of awnings Pilot Point, Texas, 1906. Historic louvers should be retained for ventilation.

  • In warm climates, make use of existing, deep overhangs to provide shade during the hottest part of the day while allowing sunlight to come in during cold months and cooler parts of the day. Overhangs also keep roof drainage away from building foundations, often negating the need for gutters and downspouts.

View looking up to the ceiling where one can see hvac ducts and the building's original monitor that runs along the length, the long sides of the monitor has louvers to light or ventilate the area under the roof.

Adaptive use of a power plant in Richmond, VA retained the use of the monitor for sunlight and ventilation.

  • Operable historic windows, louvers, and monitors substantially reduce demand for heating and cooling during temperate months. Educate occupants on effective use of windows. Open the top sash of a double hung window to allow warm air from the top of the room to escape. Open the bottom sash on the shade side of a room to pull in cool air while displacing warm air. It may be possible to maintain the operability of historic transoms over doors to provide cross ventilation in certain situations. However, most fire codes will not allow the use of operable transoms in certain types of facilities because it defeats fire walls and allows smoke/fire to easily migrate from space to space.

    • Preserve high ceilings to allow air to circulate and light to enter into a building.

    • Courtyards in hot climates traditionally provided shaded outdoor spaces and well-ventilated indoor spaces. Fountains and other water features reduce the energy required to cool these spaces and make courtyards more comfortable during the summer and temperate months. As water condenses, air is cooled. Located in a walled area, cool air is trapped low, providing relief and humidity in hot dry climates. Retain historic open courtyards and water features to achieve these benefits.

    • Historic masonry buildings are exceptionally durable and benefit from significant thermal mass. Thermal mass helps regulate the temperature inside by storing heat and cold within the mass of the wall.

On-Site Renewable Energy

A project should be assessed for the potential to incorporate on-site renewable energy including solar, wind, geothermal, low-impact hydro, biomass, and bio-gas strategies in order to reduce environmental and economic impacts associated with fossil fuel energy use.

2 photos; on left is a red brick building with white panels and windows flanking a red door, a wall of widows along the second floor, and a large red tower stucture along the right side; on the right is a small metal plate covering a geothermal heating well installed in the sidewalk abutting a planter box

Several buildings in this downtown Durham, North Carolina commercial district share a geothermal heating system. This system was sensitively installed and is evidenced only by a small metal plate in the side alley covering one of the wells.

2 photos; on the left is a large brick warehouse building with double height black garage doors and large windows along the second story; on the right is a flat roof with solar panels installed on it

To retain the character of this historic building in Richmond, Virginia, the visibility of solar panels must be limited. Flat roofs work best for their installation. Panels should have a more horizontal orientation and be inset from the perimeter walls. Existing parapets may also hide these new features.
Photos courtesy of the National Park Service

Trinity Church in Boston, MA

Trinity Church in Boston's Copley Square installed a series of six geothermal wells close to the church's exterior. The wells are the heart of a new energy system designed to make it possible to renovate and use the church's undercroft—the space below the sanctuary--much of which currently remains a basement with a dirt floor.When completed, it will provide the church with social space able to accommodate the parish's needs.The system will also support renovations planned for the parish house. Trinity Church's plans are in keeping with resolutions adopted in 2000 by the Episcopal Church's General Convention and Massachusetts' Diocesan Convention, both encouraging the use of environmentally safe and sustainable energy sources.

Green Power

Wind turbines in a field along side a road

Buying energy generated off-site is a green alternative with no impact on the character of a historic building. Remotely located wind turbines in southern Minnesota.
Photo courtesy of Audrey Tepper

A "no impact" way to capitalize on renewable resources is to buy energy produced remotely. This avoids the need for expensive "add-ons" that have the potential to adversely affect the character of a historic building. Wind power and ground-source energy can be purchased from the local utility company at reasonable rates.

Reuse of Historic Windows

Historic windows are important features and their energy efficiency can be upgraded.LEED® encourages the use of highly energy efficient windows, which may require the removal of historic windows that are potentially reusable. Original windows are character-defining features of historic buildings and their removal can significantly alter a structure's integrity, thus conflicting with preservation goals and the Secretary's Standards.

With proper maintenance, windows built from old growth wood can function indefinitely and their performance can be substantially bolstered by using storm windows, caulk, and weather-stripping.Studies have shown that these simple improvements can result in efficiency similar to that of new insulated glass windows.Some modern windows have a relatively short lifespan and can be difficult, if not impossible, to repair.Once modern windows fail, there are few ways they can be recycled, and they will likely end up in landfills. This begins an environmentally insensitive cycle of removal and replacement.

2 photos: on left is the view of the front of a 19th century brick house showing the black front door and two windows off to the left side with potted plants in the front; on the right a close up view of a black shutter and window on a 19th century brick house. The historic storm windows protect the original windows.

Early nineteenth century home where historic storm windows protect the original windows, thereby retaining character and saving energy.
Photos courtesy of Audrey Tepper

Therefore, the most responsible approach is to retain historic windows that last and retrofit them with increased effectiveness rather than install new windows that, without exception, will fail and cannot be repaired. LEED® should consider awarding points for the repair and continued use of old windows where significant improvements in energy efficiencyare demonstrated, as well as where significant amounts of historic fabric are being retained and reused.

Specifically, many historic buildings featured hinged, wood storm windows that can be reused. Historic windows were constructed of dense, old growth wood. The life cycle of the majority of modern replacement windows is much shorter. Historic windows can be reused in an energy efficient manner. A traditional single-glazed, double hung window has an R-value of 1, compared to R3 for a new double-glazed, low-e, double hung window. If the historic wall assembly has an R-value in the teens, taking a window from R1 to R3 will not provide sufficient energy savings to offset the cost of replacement windows and associated waste. The primary cause of infiltration can be addressed with jamb insulation, weather stripping, and trim repair. For an extra layer between the occupant and the elements, a storm window can be mounted to the existing window—interior or exterior—with little change to the character of the original unit.In response to the need to better quantify and document the performance of historic windows, some studies are being done.The Window Preservation Standards Collaborative is one initiative that is being taken to perform testing and develop data on historic window performance and repair standards.

Colorized photograph of the U.S. Custom House in Denver, Colorado
Skylight at Original Letter Handling Room: Byron White Courthouse; Denver, Colorado

U.S. Custom House, Denver, Colorado.
Photo Credit: GSA

Skylight at Original Letter Handling Room: Byron White Courthouse; Denver, Colorado.
Photo Credit: GSA

Materials and Resources

Source Reduction and Waste Management

Consider use of appropriate salvage historic materials for restoration of lighting, hardware, and other specialty items. Most mid-sized cities have resources for salvaged building materials. Retain, repair, or upgrade historic fixtures, rather than replace them.

2 photos: on left is the interior view of a room in the Department of the Interior, Headquarters Building showing a refrigerator along the left, a large window at one end filled with plants, a round table and chairs in front of the window, and a hanging light fixture; on the right the exterior of the Department of the Interior, Headquarters Building, Washington, DC

Department of the Interior, Headquarters Building, Washington, DC. Ongoing work to achieve a LEED® Silver rating includes: utilization of energy efficient appliances, carpeting and furnishings with a high recycled content,efficient mechanical systems installed with minimal impact on the historic materials, energy saving lighting fixtures, maximizing interior daylight, and installing interior blast storm windows were added for security and energy efficiency. Historic windows were retained and their energy efficiency was bolstered by the addition of the blast windows.

Optimize Use of Indoor Air Quality (IAQ) Compliant Products

Early paints and stains featured pigments made from natural plant materials and minerals.Use low volatile organic compounds (VOC) finishes.

Exterior and Interior Materials

While LEED® does not yet focus on the value of durable materials in sustainable building; use of durable, renewable natural materials conserves resources in the long-term and is one of the significant sustainable aspects of historic buildings. Consider the embedded energy of existing materials in approaching rehabilitation of interior spaces.

Interior view of trusses and catwalk on conversion of a former manufacturing building
Interiour view of a building the in process of being converted showing the original brick columns, wooden trusses, and skylight


Exterior of a large red brick building with a barn shaped roof

Conversion of a former manufacturing building in Richmond, Virginia. Durability of Materials: few points are given for the durability and long life cycle of traditional building materials. Energy is also saved if it is not necessary to manufacture, transport, and install new materials. Durable trusses, historic brick, and useable skylights are all materials that both define the character of this industrial building and can be incorporated into the building's new use.

Indoor Environmental Quality (IEQ)

Outside Air Introduction and Exhaust Systems

Before the advent of mechanical air conditioning, most historic buildings featured natural ventilation, usually based on the chimney effect. Wherever practical, provide for natural ventilation to maximize efficient air flow, reduce occurrence of sick building syndrome, and increase occupant alertness.

Controllability of Systems: Lighting

Many early offices took advantage of a combination of natural light and task lighting. Retain large window openings and specify low height, directional lamps that illuminate work surfaces effectively. Consider installing sensors to maximize use of natural light by activating ambient electric light only as needed.

Daylighting and Views: Daylighting

Retain tall windows to allow natural light to penetrate a building. With the added benefit of higher ceilings, natural light can travel far into a space.Buildings in a "C" or "E" plan form were common and essentially functioned to facilitate natural light and ventilation.Additionally, skylights provide a flood of natural light, and were often used on the north face of a roof so not to produce glare.

Historic building with small skylights installed on the turret
Exterior of a historic red brick building, a former power plant converted to office space, with very large windows that were retained during the converstion

Unsympathetic installation of skylights on a historic turret. Installation of skylights can enhance daylighting of a historic building, but only when these new features do not compromise the integrity of a historic building. In this case, the skylights are not sympathetic.
Photo courtesy of Audrey Tepper

Retention of historic windows in this former power plant (converted to office space) in Richmond, Virginia.
Photo courtesy of the National Park Service


Relevant Codes, Standards, and Guidelines

Codes

Standards and Guidelines

Additional Resources

WBDG

Design Objectives

Historic Preservation, Sustainable

Systems & Specifications

Federal Green Construction Guide for Specifiers

Organizations and Associations

Online Articles

Publications

Government Agency Historic Preservation Resources

Other Agencies/Organizations

Incentives for Historic Buildings

How to Find a Preservation Professional

(e.g., preservation consultants, architectural historians, architectural or fine arts conservators, technical consultants, including structural, mechanical, electrical, and civil engineers, etc.)

Technical Information on Historic Materials

Training