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Milwaukee County. Often times windows are repairable as seen here with historic wood casement windows with lead caming. Source: WHS - State Historic Preservation Office.

When you are renovating a historic house or building, you may need to replace original details that are either missing or severely altered. To make replacement decisions, you should carefully consider whether your choices will do the following:

• Respect the historic character of your house or building.
• Follow preservation best practices.

Your goal should always be to avoid creating a false sense of historical appearance to your house or building.

Choose In-Kind Replacements

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Milwaukee County. If a wood porch post is missing or damaged beyond repair, a new one can be created by carefully measuring an original post. Source: WHS - State Historic Preservation Office.

The ideal approach when replacing missing or damaged historic features is to replace “in-kind,” which means matching the original feature in its design and materials. The aim of your rehabilitation project should be to match features so closely that you cannot tell the difference between the original and the replacement. New designs should match the original based on these five characteristics: 

• Dimensions
• Color
• Scale
• Profile
• Materials

Follow Your Design Guideline Standards

If your historic house or building is subject to design review, your community’s design guidelines will likely include recommendations for in-kind replacement of original features. Most design guidelines adopted by Wisconsin communities are based on the Secretary of the Interior Standards for Rehabilitation published by the National Park Service. These standards cover recommendations for replacement of historic materials in Standard Number 6, which states:

“Deteriorated historic features will be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature will match the old in design, color, texture and, where possible, materials. Replacement of missing features will be substantiated by documentary and physical evidence.”

You should follow this standard when making your decisions to replace missing features on your historic house. Your house or building might have enough of the original materials remaining to allow you to replicate new features.

Research Before You Replace

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Dane County. These decorative wood porch brackets require repair. If deteriorated beyond repair, the brackets can be reproduced using wood and painted to match the original design. Source: WHS - State Historic Preservation Office.

If an original feature is missing entirely from your house or building, look for physical or historical evidence that may serve as a basis for reconstruction with new materials. Here are a few examples:

• If most of your original windows are missing but one original sash remains intact, use that sash as the basis for replacing all of your windows with a similar design.
• If a section of wood cornice remains at the roofline of your structure, use that piece to recreate the entire cornice.
• If you are restoring your front porch, look for “ghosts” of the original porch columns outlined in paint on the front walls of your house or other features.

If no physical evidence exists for your missing features, try to find historic photographs or illustrations of your structure. You might be surprised at how much information you can find about your house with some basic detective work. There are several ways to research the history of your property, including these approaches:

• Contact previous owners of your property.
• Visit your local historical society or library.
• Research the Sanborn Fire Insurance maps available for your community.

Match Original Materials and Designs

It might be easier than you think to replace missing original features, such as fireplace mantels, door knobs, bathroom fixtures and light fixtures. If your historic house or building has some original features you want to match, contact one of the following businesses for help:

• A business that specializes in historic reproductions.
• Local businesses that sell salvaged historic house features or “architectural antiques.”
• Demolition companies, which often save old brick, bathroom fixtures, doors and door hardware that can be used to match your missing features.
• Local historic preservation or other nonprofit groups that salvage old building materials for sale.

If you cannot find any of these businesses in your community, search the hundreds of companies that advertise historic house products on the web.

Many historic houses are of wood frame construction, and carpenters or milling companies often can easily match a missing feature. For example, if your house is missing decorative eave brackets at the roofline, you can remove a remaining bracket and take it to a milling company to be copied. When you replace missing wood features, keep in mind that the original materials would have been long-lasting, old-growth wood. To make the new wood feature last as long as the old, use the best quality wood you can afford. Cypress and fir are good options because they have tighter grains than most pressure-treated pine and similar woods.

If your house or building is constructed with masonry or masonry veneer, you may need to replace individual pieces or sections of brick or stone. Bricks and stones are made with many textures and colors, so you might find it difficult to get an exact match. A local mason might be able to match your missing brick or stone and other features, such as lintels over doors or window or arches. Other historic materials like terra cotta and glazed tile may be even more difficult to match, but a local craftsperson might be able to match these materials.

Choose Appropriate Substitute and Alternative Materials

You might find that replacing in-kind is not possible or feasible. Your historic material may no longer be available, or you may not be able to find a craftsperson who knows how to match it. In these cases, you will have to find substitute or alternative materials. Substitute, or alternative, materials are products that imitate historic materials. For example, if your historic building has stone features and qualities that cannot be found today, you could substitute those features with fiberglass-reinforced concrete that closely matches the original stone’s color and texture.

Substitute and alternative materials should only be used if matching with in-kind materials is no longer a reasonable option. Many of these materials are relatively new, and their longevity, sustainability and appropriateness for historic structures could be questionable. These materials will be subject to moisture penetration, ultraviolet degradation and thermal expansion and contraction rates that differ from the original, historic materials. In some cases, the differences in moisture permeability between a substitute material and the historic material cause further deterioration.

Before you choose a substitute or alternative material, make certain it meets these three basic criteria:

• The material must be compatible with the historic material in appearance.
• The material’s physical properties must be similar to those of the historic material or be installed in a manner that tolerates differences.
• The material must meet certain basic performance expectations over an extended period of time.