Architectural Millwork: Molded vs. Fabricated
OLD IS NEW AGAIN
Top to bottom: Wisconsin Electric Building, Wauregan Hotel, Durant Hotel
Molded high-density polyurethane millwork has been used in a number of large, high-profile historic reproductions around the country. For example, the Wisconsin Electric Building in Milwaukee, Wisconsin, a heritage building from the turn of the 19th century, received a complete restoration beginning in 1996. A specialized manufacturer worked closely with the building architect and designer to create custom stamped metal cresting (shown above), and to ensure long-term stability and design approval. The original cresting was removed in World War II due to maintenance issues. Using archive photos, the manufacturer was able to reconstruct the cresting in high-density polyurethane and prefinish it in a copper patina to replicate the authentic copper roofing.
When the Wauregan hotel was built in 1855 in Norwich, Connecticut, it was considered “the finest hotel between New York and Boston.” A complete renovation was recently completed, transforming the building into modern, upscale apartments. The historic character and charm were preserved, for example, with the beautiful exterior window elements created from molded polyurethane (shown above).
From 1920 to 1973, the Durant Hotel was the premier hotel in booming Flint, Michigan, hosting special events, conventions, dignitaries, and celebrities for many generations. Now, the recent historic renovation of the landmark building, the result of a partnership of public and private organizations and foundations, is playing an important role in the overall revitalization of Flint. Architectural features were preserved, while creating contemporary urban-style lofts and commercial space on the first floor. Many of the classic features of the new Durant, such as interiors, columns, ornamental details, and ballroom ceiling medallions, were crafted using molded polyurethane.
In a similar project, television’s pioneer home improvement series This Old House® recently celebrated 25 years on the air by completely renovating an 1849 Greek Revival-style farmstead in the suburban Boston area, taking the house from simple to modern, while preserving its historical depth and maintaining the desirable style and detail of rural New England. Custom trim, casings, and moldings were created for the project, merging the benefits of polyurethane moldings with true-to-period custom design and detailing.
Code Considerations
Most polyurethane molding products in general are not fire rated. They can be used for most residential interiors and exteriors, and most commercial exteriors. But, some manufacturers have the capabilities to provide polyurethane millwork products with either Class A (1) or Class B (2) fire ratings as tested by Underwriters Laboratories in accordance with UL 723: Test for Surface Burning Characteristics of Building Materials. (A full-service manufacturer would also be able to mold millwork from noncombustible materials like gypsum or concrete if the application required them.) The fire-rated polyurethane products are composed of material with specific chemical components. For some applications, fire-rated products are also finished with a specific coating.
Products of a quality manufacturer will meet structural code requirements throughout the United States, a particularly important requirement for components like railings and columns. In addition, some areas have their own state or local requirements; for example, in areas where hurricane risk is high. A manufacturer should be able to analyze code requirements, develop a testing process, design and engineer a code-compliant product, and coordinate independent testing to meet all relevant codes. Some manufacturers have extensive experience in providing these services.
MAKING MOLDING
Today’s molded millwork is created through a combination of state-of-the-art manufacturing technology and traditional craftsmanship.
The mixed polymer is dispensed into the open-faced molds, coated with the first primer coat protection.
The molds are placed in presses, while the expansion and cure is completed.
Once the cure is completed, the molds/parts are removed from the press, the parts are removed from the molds, and any machining is completed.
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