doors, windows, hardware

Best Practices

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While window restoration trumps window replacement in historic preservation, it may not be the best option for all projects.


The interior finishes, slate roof, skylight and HVAC system of the Romanesque-style U.S. Courthouse and Federal Building (1899) in Milwaukee, WI, were restored and upgraded between 1983 and 2003. From 2007 to 2008, the building’s deteriorated windows and doors were restored by Crestview, FL-based New Millennium Construction, Inc. Photo: Eric Oxendorf, Architectural Photography

By Hadiya Strasberg

As buildings age and their finishes fade and peel, their stonework becomes discolored, their woodwork deteriorates and pieces go missing, periodic cleaning, repair and upgrading are required to maintain their structural soundness and appearance. There is an argument as to whether restoration or replacement is best for the upkeep of historic buildings. In the case of wood windows, while restoration may be preferable, replacement can also assure quality results.

Three window restoration and replacement firms, New Millennium Construction, Inc., Re-View and Grabill Windows and Doors faced this issue recently when working on historic buildings.

Restored Windows
At the U.S. Courthouse and Federal Building in Milwaukee, WI, New Millennium Construction, Inc. (NMCC), of Crestview, FL, found the fenestration in various states of deterioration. "A detailed survey of the windows revealed peeling paint, broken glass, cracked and rotten wood and worn weatherstripping," says Dimitri Gioglis, owner of NMCC. The company, which specializes in historic restoration and preservation work, focused on some 650 double-hung and fixed windows, the majority of which (634) were salvageable, and 11 doors.

The windows were first stripped of 18 layers of paint, some of it lead-based. NMCC used Peel Away 1, an environmentally safe product from Dumond Chemicals of New York, NY. "Peel Away 1 allowed us to preserve more of the wood," says Gioglis. "It minimized the need to hand scrape the paint."


New Millenium first stripped 18 layers of lead-based paint from the windows. Next, cracks were restored with epoxy, and some damaged parts were replaced with matching pieces. Insulated glass replaced the original ¼-in. glazing, and new weatherstripping was installed. Photo: courtesy of New Millennium Construction, Inc.

After the paint was removed, the wood – old-growth pine – was allowed to dry. Then repairs were tackled. "A window that is 120 years old is bound to have cracks and rotten areas," says Gioglis. Where possible, cracks were restored using a wood or liquid epoxy patching compound. The areas were then sanded, primed and painted. NMCC treated partially decayed wood with a non-toxic fungicide and applications of boiled linseed oil for waterproofing. The team replaced rotten pieces with new matching pieces made of mahogany, which, Gioglis says, "is the best wood to withstand exterior conditions."

NMCC was also charged with improving energy efficiency. To this end, the company replaced the ¼-in. glass panes with 5/8-in. insulated glass. "We needed to retrofit the windows so that the thicker glass would fit," says Gioglis, "so we routed out the original sashes and installed the insulated glass."

Another way to save energy was to install a new weatherstripping system. "The old weatherstripping was deteriorated and rusted," says Gioglis, "so we installed two new layers. A copper track acted to keep the window in place and as a second barrier of the woven pile weatherstripping in the sides of the window. We used copper weatherstripping on the sides and new bulb weatherstripping on the bottom and in the meeting rails."

NMCC also restored what remained of the original solid-brass hardware. "We stripped and polished it," says Gioglis. "We brought it back to its original splendor."


The gut renovation and restoration of the 1920 Idaho State Capitol are slated for completion in August 2009. North Kansas City, MO-based Re-View manufactured 456 replacement windows for the building. Photo: courtesy of Re-View

Some of the original windows were missing, and others were beyond repair. As a last resort, Gioglis replaced 16 windows. "Replacements are the last option," says Gioglis, whose restoration philosophy is that maintaining the originals is of utmost importance. "We need to keep the history of the building and the craftsmanship and the passion that existed in the creation of these historic treasures. Replacement windows transport us to the present." But Gioglis also understands that some original details are beyond salvaging. "If you cannot save the window," he says, "I understand that you must replace it. My approach is to preserve the old ways, preferring to use the same wood, hardware and construction techniques as the original windows." The missing windows and those too damaged to repair were replaced with new units that match the originals.

In October 2008, at the end of a second season of work, New Millennium completed the window and door restoration at the U.S. Courthouse and Federal Building. After an extensive restoration from 1989 to 1996 and this project – with Quinn Evans | Architects of Ann Arbor, MI, and general contractor, Sorensen Gross Construction Services of Flint, MI – the building is finally complete.


The majority of the windows at the Idaho State Capitol were double-hung systems. For those windows that had missing or damaged sashes, Re-View replicated the sashes in Honduras mahogany. Photo: courtesy of Re-View

Restored Frames, Replica Windows
North Kansas City, MO-based Re-View, restorer and manufacturer of wood and metal windows, recently completed 456 replacement windows for the Idaho State Capitol. Todd Maxwell, co-owner of Re-View with Brooks Gentleman, says the firm does everything it can to retain original fabric, but that "in this application we had to produce new windows, because about 75 percent of the sashes had already been replaced. This project wasn't a very strong candidate for restoration."

Re-View's project, from June to October 2008, was part of a larger continuing restoration of the 1920-built Renaissance Revival-style building, which was led by Boise, ID-based architecture firm CSHQA and Salt Lake City, UT-based construction manager Jacobsen Construction. Re-View first conducted extensive field surveys to "get a good understanding of what we had and where we needed to go," says Maxwell. "We were working with 95 percent double-hung windows as well as a few casements and awnings, all of which had damaged or replaced sashes." In a previous renovation, someone had jammed insulated glass into original sashes, which had irreparably damaged them.

Also added during the previous restoration, drop ceilings for mechanical systems had "severed" the tops of some of the windows. The drop ceilings were removed, revealing the full heights of the windows. Window sizes vary throughout the building: on the second floor, the windows measure 68 ins. wide x 116 ins. tall; the fourth-floor windows are the smallest at 64 ins. wide x 81 ins. tall. Re-View replicated the window sashes in Honduras mahogany. "The original species was old-growth pine," says Brooks Gentleman. "But it's extremely expensive to use old-growth wood these days, so we substituted Honduras mahogany, which is very durable as an exterior wood." The new wood was stained to match the interior trim.


Originally constructed in 1923, Denver, CO’s Steel Building was restored in time for the 2008 Democratic National Convention, which was held just one block from the historic landmark building. The façade of terra-cotta panels and decoration was cleaned and 176 windows were replicated by Grabill Windows and Doors to match the originals. Photo: John Forney, Photographer

Re-View replaced the single-paned glazing with energy-efficient insulated glass, installed new weatherstripping and added new weights for counterbalance. "Finding the right balance took a little bit of fiddling around," says Maxwell. "We needed to get it just right."

Architectural Resource Center of Northwood, NH, restored the hardware. "The hardware was very much intact," says Gentleman. "Architectural Resource Center will remove paint finishes and apply a clear coat finish to protect the pieces and keep them a consistent color. Then, the hardware will be reinstalled in its original location."

One portion of the project did allow for restoration. Most of the sills and frames were in great shape due to the dry climate, so they were restored on site. "We kept what we could," says Maxwell. "This was a great project to work on."

Replica Windows, Restored Hardware
Due in part to its proximity to the 2008 Democratic National Convention, the windows of the landmark Steel Building in Denver, CO, were replaced during a restoration and not restored. "We were working toward finishing it by July 2008, because the Democratic National Convention was held in Denver in August," says Greg Grabill, owner of Almont, MI-based Grabill Windows and Doors – a manufacturer of custom wood and metal-clad windows and doors. "The building has a prominent place on the 16th Street Mall downtown and we wanted to present Denver's best face. Restoration would have taken longer."

Vacant and boarded up since 1988, the Steel Building, also known as the Fontius Building and the Sage Building, did meet its deadline. Denver-based architecture firm klipp, with construction manager Milender White Construction Co. of Golden, CO, restored the 1923 building and Grabill Windows and Doors of Almont, MI, manufactured the replacement windows.


The top three floors of the four-story building in Denver feature 136 pivot and double-hung windows with weight-and-pulley systems. Grabill Windows and Doors took special care in engineering the window hardware due to the additional weight of insulated glass. Ball bearings were added to each window. Photo: John Forney

Grabill fabricated 176 windows in Spanish cedar for the building. "Many of the windows were missing and the spaces boarded up," says Grabill. "Any originals that we did find had degraded rails and sills from many years of exposure to the sun and negligence and were non-operable." Using these broken windows, original blueprints and old photographs, Grabill was able to deduce how the original windows were built and to make exact replicas of the sashes and sills. "The hardware was actually the key to figuring out how the windows operated," says Grabill. "A center pivot window is pretty rare, and we hadn't worked on this type before."

The hardware was also crucial to getting the job. "We did a full-size mockup of a 48-in.-wide x 80-in.-tall pivot window with 40-in.-tall hopper transom incorporating the original hardware, profiles and trims," says Grabill. "I believe that our innovation and our impulse to duplicate as much of the existing fabric as possible were really appreciated by the architects and historic preservationists." Grabill restored about one-third of the original brass, lever-activated pivot hardware; the remainder was recast by investment casting company Aristo Cast of Altamont, MI.

Grabill replaced the single-paned glazing with insulated glass and supplemented the old hardware with lead ball bearings. New weatherstripping was integrated, which, Grabill says, was challenging. "Since the sash rises ¾-in. up to pivot, the old windows used a floating piece of wood inside a pocket in the mullion that just bumped up when one raised it," he says. "We devised a teeter-tooter mechanism between the transom and the window that lifted up the weatherstrip bar of the sash when raised." By replicating the original windows and using original hardware, Grabill was able to create an authentic product. "Sticking with the original design and staying accurate to the original was most important," he says.

When windows are salvageable, these window restoration and manufacturing companies agree that restoration is a great option. In many cases, however, restoration is too lengthy or expensive a process or is just not viable due to the level of deterioration of the wood. As Grabill says, the end product is "just as good either way."

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