<photo>Detail of preserved exterior wood; Link to National Park Service
STANDARDS FOR PRESERVATION AND GUIDELINES FOR PRESERVING HISTORIC BUILDINGS
detail photo of historic building with awnings

Although the work in the following sections is quite often an important aspect of preservation projects, it is usually not part of the overall process of preserving character-defining features (maintenance, repair, and limited replacement); rather, such work is assessed for its potential negative impact on the building's historic character. For this reason, particular care must be taken not to obscure, alter, or damage character-defining features in the process of preservation work.   

Masonry/Wood/Architectural Metals

Recommend
Installing thermal insulation in attics and in unheated cellars and crawlspaces to increase the efficiency of the existing mechanical systems.

Installing insulating material on the inside of masonry walls to increase energy efficiency where there is no character-defining interior molding around the windows or other interior architectural detailing.

Not Recommended
Applying thermal insulation with a high moisture content in wall cavities which may damage historic fabric.

Installing wall insulation without considering its effect on interior molding or other architectural detailing.

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Windows

Recommend
Utilizing the inherent energy conserving features of a building by maintaining windows and louvered blinds in good operable condition for natural ventilation.

detail photo showing historic windows with exterior shutters

Early builders and architects dealt with the poor thermal properties of windows in two ways. First, the number of windows in a building was kept to only those necessary to provide adequate light and ventilation. Second, to minimize the heat gain or loss from windows, historic buildings often included interior or exterior shutters, interior venetian blinds, curtains and drapes, or exterior awnings. Photo: NPS files.

Improving thermal efficiency with weatherstripping, storm windows, caulking, interior shades, and if historically appropriate, blinds and awnings.

Installing interior storm windows with air-tight gaskets, ventilating holes, and/or removable clips to insure proper maintenance and to avoid condensation damage to historic windows.

Installing exterior storm windows which do not damage or obscure the windows and frames.

Not Recommended
Removing historic shading devices rather than keeping them in an operable condition.

Replacing historic multi-paned sash with new thermal sash utilizing false muntins.Installing interior storm windows that allow moisture to accumulate and damage the window.

Installing new exterior storm windows which are inappropriate in size or color.

Replacing windows or transoms with fixed thermal glazing or permitting windows and transoms to remain inoperable rather than utilizing them for their energy conserving potential.

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Entrances and Porches

Recommend
Maintaining porches and double vestibule entrances so that they can retain heat or block the sun and provide natural ventilation.

photo of 19th century building with shade trees, roof overhangs, awnings and shutters

This 19th c. building in Massachusetts employed several energy-conserving features in its historic design, including shade trees, roof overhangs, awnings and shutters. Photo: HABS collection, NPS.

Not Recommended
Changing the historic appearance of the building by enclosing porches.

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Interior Features

Recommend
Retaining historic interior shutters and transoms for their inherent energy conserving features.

Not Recommended
Removing historic interior features which play an energy conserving role.

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Mechanical Systems

Recommend
Improving energy efficiency of existing mechanical systems by installing insulation in attics and basements.

Not Recommended
Replacing existing mechanical systems that could be repaired for continued use.

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Building Site

Recommend
Retaining plant materials, trees, and landscape features which perform passive solar energy functions such as sun shading and wind breaks.

Not Recommended
Removing plant materials, trees, and landscape features that perform passive solar energy functions.

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Setting(District/Neighborhood)

Recommend
Maintaining those existing landscape features which moderate the effects of the climate on the setting such as deciduous trees, evergreen wind-blocks, and lakes or ponds.

Not Recommended
Stripping the setting of landscape features and landforms so that the effects of wind, rain, and sun result in accelerated deterioration of the historic building.

 

-GUIDELINES-

The Approach

Exterior Materials
Masonry
Wood
Architectural Metals

Exterior Features
Roofs
Windows
Entrances + Porches
Storefronts

Interior Features
Structural System Spaces/Features/Finishes
Mechanical Systems

Site

Setting

Special Requirements
Energy Efficiency
Accessibility
Health + Safety

The Standards

 

  HISTORICAL OVERVIEW - preserving - REHABILITATING - RESTORING - RECONSTRUCTING

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Historical Overview