Sustainable Historic Preservation

by the WBDG Historic Preservation Subcommittee

Last updated: 02-20-2007

Introduction

Historic buildings are inherently sustainable. 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 30% of the embedded energy of maintenance and operations for the entire life of the building. Sustainability begins with preservation.

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.

The U.S. Green Building Council recently adopted LEED-EB® as 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:

1) 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 runoff water is required provide an impervious barrier below a pervious surface to direct runoff to an oil-water separator and/or a treatment facility.

2) Water Efficiency

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 traditional water conservation methods. Specify low flow toilets or consider options similar to historic technology.

3) Energy and Atmosphere

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.
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.
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.

Fire House; Pilot Point, Texas, 1906

Operable windows 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.

Reuse of Historic Windows

Historic windows are major character defining features. Contrary to some interpretations, meeting LEED® guidelines does not require replacing historic windows. 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. 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 modern replacement windows is much shorter.

Left: U.S. Custom House, Denver, Colorado (GSA)
Right: Skylight at Original Letter Handling Room: Byron White Courthouse; Denver, Colorado (GSA)

4) 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. Upgrade, rather than replace, historic fixtures.

Optimize Use of 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.

5) Indoor Environmental Quality

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.

Relevant Codes and Standards

Standards and Guidelines

Additional Resources

WBDG

Organizations and Associations

Online Articles

Publications

Environmental Resource Guide The American Institute of Architects.
Preservation Brief 44: The Use of Awnings on Historic Buildings by National Park Service. 2004.
Sustainable Architecture: White Papers Earth Pledge, 2000.
Thermal Delight in Architecture by Heshong, Lisa. Boston, MA: MIT Press, 1999.

Government Agency Historic Preservation Resources

Department of the Army
Agency's Historic Preservation Policy, Procedures, Guidance, Relating to Buildings and Structures
U.S. Army Environmental Center
USACE Tribal Affairs and Initiatives
Department of Navy
U.S. Navy Historic Preservation
Department of Veterans Affairs
Office of Facilities Management—Historic Preservation
National Park Service
National Register of Historic Places
Technical Preservation Services Branch
U.S. General Services Administration
Historic Preservation

Other Agencies/Organizations

Incentives for Historic Buildings

Tax 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.)

The American Institute of Architects
American Institute for Conservation of Historic and Artistic Works
The Association for Preservation Technology International
Federal Agency Lists of Pre-qualified Bidders (GSA, Smithsonian) including federal methods of solicitation and selection
Federal Preservation Officers
Local Historical Societies (contact your SHPO for list of local organizations)
National Trust for Historic Preservation
State Historic Preservation Offices
State Nonprofit Preservation Alliances