The Lustron Guidelines

Preservation Guidelines

In this section you will learn about the the Guidelines and how they can be applied to the Lustron. If you have not yet been introduced to the Secretary of the Interior’s Standards, we suggest you start there. Click here to Meet the Standards.

The Guidelines for Preserving, Rehabilitating, Restoring and Reconstructing Historic Buildings were created to provide guidance to those involved with the stewardship of historic properties (homeowners, property managers, consultants, contractors, etc.) prior to “treatment” or work on a property begins. The Guidelines were created to assist in applying the Standards. They don’t give case-specific recommendations. For example, the guidelines will not give specific advice on how to repair your Lustron windows, rather they provide general guidance on the repair of metal windows.

As stated by the National Park Service, the preservation guidelines are directed at specific items: architectural metals, roofs, windows, entrances and porches, structural systems, interior spaces, interior features and finishes, mechanical systems, and site. For each item, the guidelines describe actions that are recommended and not recommended. The actions begin with the least invasive-identify, retain, and preserve; stabilize; protect and maintain-then move to repair, and finally limited replacement in kind. The guidelines also address the issues of energy efficiency, accessibility, and health and safety considerations.”
To view the original preservation guidelines click here. The following guidelines have been slightly modified to be relevant for Lustrons.

Before you begin a project, review the Guidelines below.

Architectural Metals

Identifying, retaining, and preserving architectural metal features (roof and wall panels, built-ins, etc.) that are important in defining the overall historic character of the building; and their finishes and colors. Identification of the type of metal is also critical to differentiate between metals prior to work. Each metal has unique properties and thus requires different treatments.

For example, the Multiple Property Submission for Lustron Houses in Georgia states that for a property to meet the National Register registration requirements, “the house must be a one story ranch-type Lustron with exterior two-foot square, porcelain enamel steel panels and porcelain-enameled, tile-like roof shingles. The interior must retain a significant portion of the nameled steel ceiling and wall panels. The hose must be manufactured by the Lustron Corporation and maintain a high degree of integrity by retaining most of its metal construction, an intact floor plan, aluminum casement windows, enameled steel, tile-like roof shingles and a concrete slab foundation.”

Protecting and maintaining architectural metals from corrosion by providing proper drainage so that water does not stand on flat, horizontal surfaces.

For example, keeping your gutters clean, and ensuring that they drain away from the house will help prevent corrosion.

Cleaning architectural metals and enameled surfaces, when appropriate, to remove corrosion prior to repainting or applying other appropriate protective coatings.
Identifying the particular type of metal prior to any cleaning procedure and then testing to assure that the gentlest cleaning method possible is selected or determining that cleaning is inappropriate for the particular metal.
Cleaning soft metals such as aluminum with appropriate chemical methods because their finishes can be easily abraded.
Using the gentlest cleaning methods for steel-a hard metal-in order to remove corrosion.
Applying appropriate paint or other coating systems after cleaning in order to decrease the corrosion rate of metals or alloys.
Evaluating the existing condition of the architectural metals to determine whether more than protection and maintenance are required, that is, if repairs to features will be necessary.
Repairing, stabilizing, and conserving fragile architectural metals using well-tested consolidants, when appropriate. Repairs should be physically and visually compatible and identifiable upon close inspection for future research.
Repairing architectural metal features by patching, piecing-in, or otherwise reinforcing the metal using recognized preservation methods. The new work should be unobtrusively dated to guide future research and treatment.
Replacing in-kind extensively deteriorated or missing parts of architectural metal features with parts salvaged from disassembled Lustrons or identical, newly fabricated parts. The new work should match the old in material, design, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering architectural metal features which are important in defining the overall historic character of the building so that, as a result, the character is diminished.

For example, replacing the roof, wallpapering your interior, replacing the original windows or pocket doors, or covering the exterior panels could diminish or destroy the architectural character of the house.

Replacing historic metal features instead of repairing or replacing only the deteriorated metal.
Changing the type of finish or its historic color or accent scheme.

For example, the Lustron panels were never intended to be painted. Painting the interior or exterior of your Lustron would change the type of finish and depending on your color selection, change the historic color and accent scheme.

Failing to stabilize deteriorated or damaged architectural metals until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to identify, evaluate, and treat the causes of corrosion, such as moisture from leaking roofs or gutters.
Placing incompatible metals together without providing a reliable separation material. Such incompatibility can result in galvanic corrosion of the less noble metal, e.g., copper will corrode steel and aluminum.
Exposing metals which were intended to be protected from the environment.
Applying paint or other coatings to metals such as aluminum that were meant to be exposed.

Once again, the Lustron was never meant to be painted on the interior or exterior. Painting is not recommended.

Using cleaning methods which alter or damage the historic color, texture, and finish of the metal or enamel coating; or cleaning when it is inappropriate for the metal or enamel coating.

Although the porcelain enamel finish is quite durable, it can be damaged by abrasive or caustic cleaning materials. Always start with the most gentle means possible. Test your methods and materials in inconspicuous areas.

Cleaning with grit blasting which will abrade the surface of the metal or enamel coating.

Don’t sandblast or grit-blast your Lustron!

Failing to re-apply protective coating systems to metals or alloys that require them after cleaning so that accelerated corrosion occurs.
Using new colors that are inappropriate to the historic building or district.
Failing to assess pedestrian use or new access patterns so that architectural metal features are subject to damage by use or inappropriate maintenance such as salting adjacent sidewalks.
Failing to undertake adequate measures to assure the protection of architectural metal features.
Removing architectural metals that could be stabilized and conserved; or using untested consolidants and untrained personnel, thus causing further damage to fragile historic materials.
Removing architectural metals that could be repaired, using improper repair techniques, or failing to document the new work.

Repair rather than replace original materials. Work with qualified contractors and document the work on your Lustron. Take before and after pictures, save receipts, and make notes.

Replacing an entire architectural metal feature when limited replacement of deteriorated and missing areas is appropriate.
Using replacement material that does not match the historic metal feature; or failing to properly document the new work.

For example, replacing your original aluminum windows with vinyl windows would not be appropriate.

Conclusion:

To summarize, when undertaking repairs, your first priority should be to preserve existing materials. If they must be replaced-replace them in-kind. When cleaning, use the gentlest means possible.

To review the Guidelines for Architectural Metals, click here.
To learn more about Lustron Panels, click here:
To learn more about repair and maintenance of Lustron Panels click here.

Roofs

Identifying, retaining, and preserving roofs–and their functional and decorative features–that are important in defining the overall historic character of the Lustron.
Stabilizing deteriorated or damaged roofs as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining a roof by cleaning the gutters and downspouts and replacing deteriorated flashing. Roof sheathing should also be checked for proper venting to prevent moisture condensation and water penetration; and to insure that materials are free from insect infestation.

Regularly cleaning and maintaining your roof and gutters will help preserve the longevity of the roof.

Providing adequate anchorage for roofing material to guard against wind damage and moisture penetration.
Protecting a leaking roof with plastic sheets until it can be properly repaired.
Repairing a roof by reinforcing the historic materials which comprise roof features using recognized preservation methods. The new work should be unobtrusively dated to guide future research and treatment.
Replacing in kind extensively deteriorated or missing parts of roof features or roof coverings with parts salvaged from a disassembled Lustron. The new work should match the old in material, design, color, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering the roof and roofing materials which are important in defining the overall historic character of the building so that, as a result, the character is diminished.

The Lustron Roof is a defining element of the historic character of a Lustron. Removal and replacement with a roof that does not replicate the original would severely diminish the historic character.

Replacing historic roofing material instead of repairing or replacing only the deteriorated material.
Changing the type or color of roofing materials.
Failing to stabilize a deteriorated or damaged roof until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to clean and maintain gutters and downspouts properly so that water and debris collect and cause damage to roof fasteners, sheathing, and the underlying structure.
Allowing roof fasteners, such as screws and clips to corrode so that roofing material is subject to accelerated deterioration.
Permitting a leaking roof to remain unprotected so that accelerated deterioration of historic building materials occurs.
Removing materials that could be repaired, using improper repair techniques, or failing to document the new work.
Using material for the replacement material that does not match the historic roof feature; or failing to properly document the new work.

Conclusions

The Lustron Roof is an integral part of the character defining features of the Lustron home. Regular maintenance will help ensure its longevity.

For information on the Lustron Roof and Gutters, click here.
For information on how to repair the Roof and Gutters, click here.

Windows

Conducting an in-depth survey of the condition of existing windows early in preservation planning so that repair and upgrading methods and possible replacement options can be fully explored.
Stabilizing deteriorated or damaged windows as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining the architectural metals which comprise the window frame, sash, muntins, and surrounds through appropriate surface treatments such as cleaning.
Making windows weathertight by re-caulking and replacing or installing weatherstripping. These actions also improve thermal efficiency.
Evaluating the existing condition of materials to determine whether more than protection and maintenance are required, i.e. if repairs to windows and window features will be required.
Repairing window frames and sash by patching, piecing-in, consolidating or otherwise reinforcing them using recognized preservation methods. The new work should be unobtrusively dated to guide future research and treatment.
Replacing in kind extensively deteriorated or missing parts of windows with parts salvaged from a disassembled Lustron. The new work should match the old in material, design, color, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering windows or window features which are important in defining the historic character of the building so that, as a result, the character is diminished.

Replacing the original aluminum windows with new windows that do not match the materials, form and profile of the original windows would severely impact the overall character of the Lustron home.

Changing the historic appearance of windows by replacing materials, finishes, or colors which noticeably change the sash, depth of reveal, and muntin configuration; the reflectivity and color of the glazing; or the appearance of the frame.
Obscuring historic window trim with new metal or other material.
Replacing windows solely because of broken glass, stuck sash, and high air infiltration. These conditions, in themselves, are no indication that windows are beyond repair.
Failing to stabilize a deteriorated or damaged window until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to provide adequate protection of materials on a cyclical basis so that deterioration of the window results.
Retrofitting or replacing windows rather than maintaining the sash, frame, and glazing.
Failing to undertake adequate measures to assure the protection of historic windows.
Failing to protect the historic glazing when repairing windows.
Removing material that could be repaired, using improper repair techniques, or failing to document the new work.
Failing to reuse serviceable window hardware.
Replacing an entire window when limited replacement of deteriorated and missing parts is appropriate.
Using replacement material that does not match the historic window; or failing to properly document the new work.

Conclusion

The original aluminum windows are a character defining element of the Lustron home and should be maintained and if necessary, repaired, rather than replaced. If the window is beyond repair and salvaged windows cannot be located, the new work should match the old in material, design, color, and texture. Replace windows on a case-by-case basis, rather than wholesale replacement. Document the work done.

To read Preservation Brief 13: The Repair and Thermal Upgrading of Historic Steel Windows, click here. Although the Lustron windows are aluminum, this is still a useful document to read and provides much valuable information.
For information on the Lustron Windows, click here.
For information on the repair of Lustron Windows, click here.
For information on cleaning and repairing your Blinds, click here.

Entrances and Porches

Stabilizing deteriorated or damaged entrances and porches as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining the concrete and architectural metals that comprise entrances and porches through appropriate surface treatments such as cleaning, rust removal, and re-application of protective coating systems.
Evaluating the existing condition of materials to determine whether more than protection and maintenance are required, that is, repairs to entrance and porch features will be necessary.
Repairing entrances and porches by reinforcing the historic materials using recognized preservation methods. The new work should be unobtrusively dated to guide future research and treatment.
Replacing in kind extensively deteriorated or missing parts of repeated entrance and porch features with parts salvaged from a disassembled Lustron. The new work should match the old in material, design, color, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering entrances and porches which are important in defining the overall historic character of the building so that, as a result, the character is diminished.

Replacing or altering the original Lustron doors, or enclosing the original porches will severely diminish the historic character of the house.

Replacing historic entrance and porch features instead of repairing or replacing only the deteriorated material.
Failing to stabilize a deteriorated or damaged entrance or porch until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to provide adequate protection to materials on a cyclical basis so that deterioration of entrances and porches results.
Failing to undertake adequate measures to assure the protection of historic entrances and porches.
Removing material that could be repaired, using improper repair techniques, or failing to document the new work.
Replacing an entire entrance or porch feature when limited replacement of deteriorated and missing parts is appropriate.
Using replacement material that does not match the historic entrance or porch feature; or failing to properly document the new work.

Conclusion

The original entrance ways and when present, porch, represent significant features of the Lustron home and should be retained.

Structural Systems

Identifying, retaining, and preserving structural systems–and individual features of systems–that are important in defining the overall historic character of the building.
Stabilizing deteriorated or damaged structural systems as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining the structural system by cleaning the roof gutters and downspouts; replacing roof flashing; keeping concrete and architectural metals in a sound condition; and ensuring that structural members are free from insect infestation.
Examining and evaluating the existing condition of the structural system and its individual features using non-destructive techniques such as X-ray photography.
Repairing the structural system by augmenting or upgrading individual parts or features using recognized preservation methods.
Replacing in kind those visible portions or features of the structural system that are either extensively deteriorated or missing with parts available from a disassembled Lustron. The new work should match the old in materials, design, color, and texture; and be unobtrusively dated to guide future research and treatment.
Considering the use of substitute material for unexposed structural replacements, such as roof trusses. Substitute material should, at a minimum, have equal loadbearing capabilities, and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering visible features of historic structural systems which are important in defining the overall historic character of the building so that, as a result, the character is diminished.
Overloading the existing structural system; or installing equipment or mechanical systems which could damage the structure.
Leaving known structural problems untreated such as deflection of beams, cracking and bowing of walls, or racking of structural members.
Utilizing treatments or products that accelerate the deterioration of structural material.
Failing to stabilize a deteriorated or damaged structural system until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to provide proper building maintenance so that deterioration of the structural system results. Causes of deterioration include subsurface ground movement, vegetation growing too close to foundation walls, improper grading, and poor interior ventilation that results in condensation.
Utilizing destructive probing techniques that will damage or destroy structural material.
Upgrading the building structurally in a manner that diminishes the historic character of the exterior, or damages interior features or spaces.
Replacing a structural member or other feature of the structural system when it could be augmented and retained.
Replacing an entire visible feature of the structural system when limited replacement of deteriorated and missing portions is appropriate.
Using material for a portion of an exposed structural feature that does not match the historic feature; or failing to properly document the new work.
Using substitute material that does not equal the loadbearing capabilities of the historic material or design or is otherwise physically or chemically incompatible.

Conclusions

The underlying structural system of the all-steel Lustron home is a significant feature of the home.

For information on the Structural System of the Lustron home, click here.

Interior Spaces

Identifying, retaining, and preserving a floor plan or interior spaces that are important in defining the overall historic character of the building. This includes the size, configuration, proportion, and relationship of rooms and corridors; the relationship of features to spaces; and the spaces themselves.

Not Recommended

Altering a floor plan or interior spaces–including individual rooms–which are important in defining the overall historic character of the building so that, as a result, the character is diminished.

Conclusion

The original interior layout of the Lustron home is a character defining element and should be retained. Futhermore, because of the complexity of the Lustron assembly process, alteration of the interior layout could require the destruction or alteration of interior panels, and built-ins and should be avoided.

To learn more about the various Lustron Models click here.
To view an Interactive Model of the Lustron, click here.

Interior Features and Finishes

Identifying, retaining, and preserving interior features and finishes that are important in defining the overall historic character of the building, including baseboards, metal panels, light fixtures, hardware, and flooring.
Stabilizing deteriorated or damaged interior features and finishes as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining concrete and architectural metals that comprise interior features through appropriate surface treatments such as cleaning, rust removal, and reapplication of protective coatings systems.
Protecting interior features and finishes against arson and vandalism before project work begins, boarding-up windows, and installing fire alarm systems that are keyed to local protection agencies.
Protecting interior features such as panels and built-ins against damage during project work by covering them with heavy canvas or plastic sheets.
Removing damaged or deteriorated enamel coating using the gentlest method possible, then repainting or refinishing using compatible paint or other coating systems.
Evaluating the existing condition of materials to determine whether more than protection and maintenance are required, that is, if repairs to interior features and finishes will be necessary.
Repairing historic interior features and finishes by reinforcing the materials using recognized preservation methods. The new work should match the old in material, design, color, and texture; and be unobtrusively dated to guide future research and treatment.
Replacing in kind extensively deteriorated or missing parts of repeated interior features with parts salvaged from disassembled Lustrons. New work should match the old in material, design, color, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering features and finishes which are important in defining the overall historic character of the building so that, as a result, the character is diminished.
Replacing historic interior features and finishes instead of repairing or replacing only the deteriorated masonry.
Installing new decorative material that obscures or damages character-defining interior features or finishes.
Applying paint, plaster, or other finishes to enameled or aluminum surfaces.
Changing the type of finish or its color.
Failing to stabilize a deteriorated or damaged interior feature or finish until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to provide adequate protection to materials on a cyclical basis so that deterioration of interior features results.
Permitting entry into historic buildings through unsecured or broken windows and doors so that the interior features and finishes are damaged by exposure to weather or vandalism.
Stripping interiors of features such as panels and built-ins.
Failing to provide proper protection of interior features and finishes during work so that they are gouged, scratched, dented, or otherwise damaged.
Failing to take new use patterns into consideration so that interior features and finishes are damaged.
Using destructive methods such as propane or butane torches or sandblasting to remove enameled coating. These methods can irreversibly damage the historic materials that comprise interior features.
Using new enamel colors that are inappropriate to the historic building.
Changing the texture and patina of character-defining features through sandblasting or use of abrasive methods to remove paint, discoloration or plaster. This includes both exposed wood (including structural members) and masonry.
Failing to undertake adequate measures to assure the protection of interior features and finishes.
Removing materials that could be repaired, using improper techniques, or failing to document the new work.
Replacing an entire interior feature when limited replacement of deteriorated and missing parts is appropriate.
Using replacement material that does not match the interior feature; or failing to properly document the new work.

The interior finishes and features of the Lustron home, the interior wall and ceiling panels, the built elements, the pocket doors, window blinds and fixtures, are all character defining elements of the Lustron home and should be retained. Covering the walls or ceiling panels with paint, wall paper, sheet rock or other material which obscures the original surface should be avoided. If your interior panels need to be cleaned, or if paint or wall paper need to be removed, use the gentlest means possible. Repair rather than replace original pocket doors, window blinds and features. Use magnets, rather than nails or screws to hang art and other objects from the walls.

For more information on the Lustron Color Scheme, click here.
For information on the Lustron Panels, click here.
For information on cleaning an repair of your Panels, click here.
For information on your Windows click here.
For information on cleaning and repairing your Windows, click here.
For information on Cleaning and Repairing your Blinds, click here.
For information on Cleaning and Repairing your Pocket Doors, click here.

Mechanical Systems

Identifying, retaining, and preserving visible features of early mechanical systems that are important in defining the overall historic character of the building, such as vents, fans, grilles, plumbing fixtures, switchplates, and lights.
Stabilizing deteriorated or damaged mechanical systems as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining mechanical, plumbing, and electrical systems and their features through cyclical cleaning and other appropriate measures.
Preventing accelerated deterioration of mechanical systems by providing adequate ventilation of attics so that moisture problems are avoided.
Improving the energy efficiency of existing mechanical systems to help reduce the need for elaborate new equipment.
Repairing mechanical systems by augmenting or upgrading system parts, such as installing new pipes and ducts; rewiring; or adding new compressors or boilers.
Replacing in kind those visible features of mechanical systems that are either extensively deteriorated or are prototypes such as switchplates, grilles, or plumbing fixtures.
Installing a new mechanical system if required, so that it causes the least alteration possible to the building.
Providing adequate structural support for new mechanical equipment.
Installing the vertical runs of ducts, pipes, and cables in closets, service rooms, and wall cavities.
Installing air conditioning in such a manner that historic features are not damaged or obscured and excessive moisture is not generated that will accelerate deterioration of historic materials.

Not Recommended

Removing or altering visible features of mechanical systems that are important in defining the overall historic character of the building so that, as a result, the character is diminished.
Failing to stabilize a deteriorated or damaged mechanical system until additional work is undertaken, thus allowing further damage to occur to the historic building.
Failing to provide adequate protection of materials on a cyclical basis so that deterioration of mechanical systems and their visible features results.
Enclosing mechanical systems in areas that are not adequately ventilated so that deterioration of the systems results.
Installing unnecessary climate control systems which can add excessive moisture to the building. This additional moisture can either condense inside, damaging interior surfaces, or pass through interior walls to the exterior, potentially damaging adjacent materials as it migrates.
Replacing a mechanical system or its functional parts when it could be upgraded and retained.
Installing a visible replacement feature that does not convey the same visual appearance.
Installing a new mechanical system so that character-defining structural or interior features are radically changed, damaged, or destroyed.
Failing to consider the weight and design of new mechanical equipment so that, as a result, historic structural members or finished surfaces are weakened or cracked.
Installing vertical runs of ducts, pipes, and cables in places where they will obscure character-defining features.
Concealing mechanical equipment in walls or ceilings in a manner that requires excessive removal of historic building material.
Cutting through features such as walls in order to install air conditioning units.

Conclusions

The radiant heat system is an important feature of the Lustron home. It is possible to upgrade the existing system with a new furnance and retain the radiant heating system. When updating the heat, electrical or plumbing systems, care needs to be taken to minimize damage to the interior and exterior panels.

For information on the Radiant Heating System, click here.
For information on how to maintain, repair and update the Heating System, click here.
For information on updating the Electrical System click here.
For information on maintaining and updating the Plumbing System, click here.

Site

Identifying, retaining, and preserving buildings and their features as well as features of the site that are important in defining its overall historic character. Site features may include circulation systems such as walks, paths, roads, or parking; vegetation such as trees, shrubs, fields, or herbaceous plant material; landforms such as terracing, berms or grading; furnishings such as lights, fences, or benches; decorative elements such as sculpture, statuary or monuments; water features including fountains, streams, pools, or lakes; and subsurface archaeological features which are important in defining the history of the site.
Retaining the historic relationship between buildings and the landscape.
Stabilizing deteriorated or damaged building and site features as a preliminary measure, when necessary, prior to undertaking appropriate preservation work.
Protecting and maintaining buildings and sites by providing proper drainage to assure that water does not erode foundation walls; drain toward the building; or damage or erode the landscape.
Minimizing disturbance of terrain around buildings or elsewhere on the site, thus reducing the possibility of destroying or damaging important landscape features or archaeological resources.
Surveying and documenting areas where the terrain will be altered to determine the potential impact to important landscape features or archaeological resources.
Protecting, e.g., preserving in place, important archaeological resources.
Planning and carrying out any necessary investigation using professional archaeologists and modern archaeological methods when preservation in place is not feasible.
Preserving important landscape features, including ongoing maintenance of historic plant material.
Protecting building and landscape features against arson and vandalism before preservation work begins, i.e., erecting protective fencing and installing alarm systems that are keyed into local protection agencies.
Providing continued protection of historic building materials and plant features through appropriate cleaning, rust removal, and re-application of protective coating systems; and pruning and vegetation management.
Evaluating the existing condition of materials and features to determine whether more than protection and maintenance are required, that is, if repairs to building and site features will be necessary.
Repairing features of the building and site by reinforcing historic materials using recognized preservation methods. The new work should be unobtrusively dated to guide future research and treatment.
Replacing in kind extensively deteriorated or missing parts of the building or site where there are surviving prototypes such as part of a fountain, or portions of a walkway. New work should match the old in materials, design, color, and texture; and be unobtrusively dated to guide future research and treatment.

Not Recommended

Altering buildings and their features or site features which are important in defining the overall historic character of the property so that, as a result, the character is diminished.
Removing or relocating buildings or landscape features, thus destroying the historic relationship between buildings and the landscape.
Failing to stabilize a deteriorated or damaged building or site feature until additional work is undertaken, thus allowing further damage to occur to the building site.
Failing to maintain adequate site drainage so that buildings and site features are damaged or destroyed; or alternatively, changing the site grading so that water no longer drains properly.
Introducing heavy machinery into areas where it may disturb or damage important landscape features or archaeological resources.
Failing to survey the building site prior to beginning work which results in damage to, or destruction of, important landscape features or archaeological resources.
Leaving known archaeological material unprotected so that it is damaged during preservation work.
Permitting unqualified personnel to perform data recovery on archaeological resources so that improper methodology results in the loss of important archaeological material.
Allowing important landscape features to be lost or damaged due to a lack of maintenance.
Permitting the property to remain unprotected so that the building and landscape features or archaeological resources are damaged or destroyed.
Removing or destroying features from the buildings or site such as wood siding, iron fencing, masonry balustrades, or plant material.
Failing to provide adequate protection of materials on cyclical basis so that deterioration of building and site feature results.
Failing to undertake adequate measures to assure the protection of building and site features.
Removing materials that could be repaired, using improper repair techniques, or failing to document the new work.
Using replacement material that does not match the building site feature; or failing to properly document the new work.

Energy Efficiency

Architectural Metals

Recommended:
- Installing thermal insulation in attics to increase the efficiency of the existing mechanical systems.
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 wall panels or other structural systems.

Windows

Recommended:
- Utilizing the inherent energy conserving features of a building by maintaining windows and louvered blinds in good operable condition for natural ventilation.
- Improving thermal efficiency with weatherstripping, storm windows, caulking, interior shades, and historically appropriate Venetian blinds.
- 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.
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 with fixed thermal glazing or permitting windows to remain inoperable rather than utilizing them for their energy conserving potential.

Entries and Porches

Recommended:
- Maintaining porches so that they can retain heat or block the sun and provide natural ventilation.
Not Recommended:
- Changing the historic appearance of the building by enclosing porches.

Interior Features

Recommended:
- Retaining historic interior Venetian blinds for their inherent energy conserving features.
Not Recommended:
- Removing historic interior features which play an energy conserving role.

Mechanical Systems

Recommended:
- Improving energy efficiency of existing mechanical systems by installing insulation in attics.
Not Recommended:
- Replacing existing mechanical systems that could be repaired for continued use.

Building Site

Recommended:
- 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.

Accessibility

Identifying the historic building’s character-defining spaces, features, and finishes so that accessibility code-required work will not result in their damage or loss.
Complying with barrier-free access requirements, in such a manner that character-defining spaces, features, and finishes are preserved.
Working with local disability groups, access specialists, and historic preservation specialists to determine the most appropriate solution to access problems.
Providing barrier-free access that promotes independence for the disabled person to the highest degree practicable, while preserving significant historic features.
Finding solutions to meet accessibility requirements that minimize the impact on the historic building and its site, such as compatible ramps and paths.

Not Recommended:

Undertaking code-required alterations before identifying those spaces, features, or finishes which are character-defining and must therefore be preserved.
Altering, damaging, or destroying character-defining features in attempting to comply with accessibility requirements.
Making changes to buildings without first seeking expert advice from access specialists and historic preservationists to determine solutions.
Making access modifications that do not provide a reasonable balance between independent, safe access and preservation of historic features.
Making modifications for accessibility without considering the impact on the historic building and its site.

Health and Safety Considerations

Identifying the historic building’s character-defining spaces, features, and finishes so that code-required work will not result in their damage or loss.
Complying with health and safety codes, including seismic code requirements, in such a manner that character-defining spaces, features, and finishes are preserved.
Removing toxic building materials only after thorough testing has been conducted and only after less invasive abatement methods have been shown to be inadequate.
Providing workers with appropriate personal protective equipment for hazards found in the worksite.
Working with local code officials to investigate systems, methods, or devices of equivalent or superior effectiveness and safety to those prescribed by code so that unnecessary alterations can be avoided.
Installing sensitively designed fire suppression systems, such as sprinkler systems that result in retention of historic features and finishes.

Not recommended:

Undertaking code-required alterations to a building or site before identifying those spaces, features, or finishes which are character-defining and must therefore be preserved.
Altering, damaging, or destroying character-defining spaces, features, and finishes while making modifications to a building or site to comply with safety codes.
Destroying historic interior features and finishes without careful testing and without considering less invasive abatement methods.
Removing unhealthful building materials without regard to personal and environmental safety.
Making changes to historic buildings without first exploring equivalent health and safety systems, methods, or devices that may be less damaging to historic spaces, features, and finishes.
Using fire-retardant coatings if they damage or obscure character-defining features.