He continues: “There are a lot of manufacturers who make somewhat- compliant materials. Anyone making an all-wood window can usually meet the guidelines. There is also the option to have replacement windows custom built.” Local searches in many areas can yield local craftsmen who can custom build, but Miller cautions going a custom route for an entire building can be cost prohibitive.
Luckenbill says for projects where a historic review board or equivalent entity is involved, materials must meet a certain set of standards. Stringency varies by area. “The Secretary of the Interior’s Standards for the Treatment of Historic Properties are generally held as a minimum set of standards and guidelines for work with historic structures,” she says. “This document recommends the replacement material match where possible but allows for alternative materials that are able to replicate the design, color and texture in cases in which use of an original material is not possible.”Sometimes replacing a material in-kind can result in a selection that requires more maintenance. “For example, if we are replacing wood trim around an entrance, there are several options,” Luckenbill says. “We can choose to replace it with wood, which will require a regular painting schedule to maintain its appearance and to check for points of deterioration of the finish, which would allow moisture to penetrate and begin to degrade the material. Alternatively, we could opt to detail the trim out of PVC components, which has less maintenance. Some of our clients have the experience and personnel to support the use of replacement materials that match the original and require more frequent maintenance. Others are looking for lower-maintenance material solutions that will still maintain the integrity of the design, color and texture of the original feature.”
New construction going into historic areas might not have the same material selection guidelines, however. Miller notes Grand Rapids has different standards for new infill that leaves a lot of room for interpretation. “For instance, you are not required to use wood windows in new construction or wood siding; we have used a lot of cement board siding,” he says. “But new construction must be compatible with the surrounding context.”
Luckenbill asserts columns and balustrades are among the more challenging details to work on. “Columns pose a challenge because they were originally designed to the classical proportions of the orders of architecture documented by Vitruvius in De Architectura,” she says. “Because these relationships are proportional, the specific dimensions of a column relate to the overall dimensions of the structure. Prefabricated columns today represent a wide range of adherence to these proportions and oftentimes only come in predetermined heights. Those heights may or may not agree with the sizes of the elements originally on the structure.”
Some products incorporate entasis, the technical term for when the shaft of a column grows in diameter slightly as it gets closer to the base. “Fluted columns pose a particular challenge as the termination of the flute, or lack thereof, is an important detail contributing to the overall architectural style of the structure,” Luckenbill continues. “Some manufacturers tout the ability for a column enclosure to be modified in the field to meet field measurements; however, this flexibility can often be at the expense of the accuracy to detailing.”
Balustrades that serve a code-related function as opposed to being strictly decorative present additional challenges. “If they are also guardrails around a roof patio or are in an area that requires handrails, there are requirements in modern building codes that dictate the height of the rail and the size of the openings created by the solid portions of the structure,” Luckenbill explains. “These requirements often result in a much tighter spacer of the balusters and can increase the height. Again, keeping the proportions correct is key in achieving a successful aesthetic result.”
Luckenbill recently renovated a porch that was part of a Colonial Revival residence. Water infiltration resulted in the deterioration of the porch’s wood structure and trim. “When we were brought into the project, portions of the roof balustrade had fallen over; the paint was peeling; portions of the wood trim were rotted; and other sections were completely missing,” she remembers. Existing conditions necessitated replacing the elements. An adjacent area of the house was experiencing roof leaks so the construction team repaired the roof and replaced the balustrade in that area, as well.
Working with the client, Luckenbill selected custom-milled and standardprofile PVC trim pieces to minimize the potential for deterioration from moisture and insects. The project also required a polyurethane balustrade system and fiberglass composite columns. The newel posts were trimmed in fiber cement boards with applied PVC trim profiles and polyurethane newel post caps.
Although the structure was not within the jurisdiction of any historic review board, Luckenbill says it is a prominent structure in the community and stakeholders were invested in ensuring the renovation was thoughtfully executed.
Reviewing the Secretary of the Interior’s Standards for the Treatment of Historic Properties is a good starting point for those looking to embark on a historic retrofit project, according to Luckenbill and Miller. However, it is important to research local building codes to determine local requirements, as well as communicate with clients to meet their vision and expectations.