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Old Windows, New Outlook

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By Ariana Makau, Nzilani Glass Conservation


Repairing or adding art-glass windows in Bay Area homes increased significantly over the last year and a half. The Wall Street Journal recently ran an article by Amanda Eberstein that reported, “The city’s storied Victorians are being preserved and restored as young homeowners trade open-floor layouts for a more conducive work-from-home environment.” The East Bay (site of the architectural nexus of Bernard Maybeck, Julia Morgan, and Idora Park) affords homeowners a diverse swath of window treatments for Craftsman, Mediterranean influence, and Victorian homes, to name a few dominant styles.



The mix of architecture in Berkeley is foundational to its visual landscape. Across diverse styles, decorative “stained glass” windows are often the crowning glory of the city’s homes. Serving the dual purpose of art and architecture, they augment and enhance a space like few other architectural assets. Colored and painted glass panes cast rich light patterns within the home, and even “simple” clear glass windows can create a rainbow effect when catching the light at key times during the day. Yet for all their beauty, their primary purpose is to protect people from the elements.

Homeowners are motivated now more than ever to fix their original windows because repairing them is better for the environment than replacing them; but many people are unsure if doing so is even feasible. A key factor in maintaining these unique windows is deciding what to repair or replace. Preservation, which combines a bit of both, allows for the retention of as much of the original material as possible, to both reduce waste and maintain the historic integrity of the architecture. When windows start to bend or leak due to broken joints or cracked glass, most people notice the damage and call a specialist for help. What many often miss is another key element: lead.

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Onyx “oversaw” work for her family

at a Tudor-style home with clear, diamond-shaped windows.



Repairing failing residential windows also means ensuring personal safety. In fact, what is often referred to as “stained glass” is in truth leaded-art glass (individual pieces of clear or colored glass set into lead cames to create an artistic design). Addressing lead safety while preserving old windows can be tricky when your beloved pet’s favorite sunny grooming spot happens to be under a deteriorating leaded window actively releasing lead dust.⁠


Of course, leaded-glass windows add great value to your home, both historically and monetarily. Effective preservation of older windows is preferable, under correct health and safety precautions. Site work must always be undertaken by a leaded-glass specialist who also has certified lead-worker training. 


After the restoration was complete, Onyx’s owner stated: “The windows look wonderful. I am so impressed with your team, their efficiency, skill, and professionalism.” (See photos to the left)

Both glass and lead are relatively inert in a newly created or rebuilt panel; so, unless you touch the lead and fail to wash your hands afterward, you can safely enjoy your windows.


Sometimes a repair can also result in an upgrade. Due to the age of this 1930s home (images up top and below), multiple windows needed to be completely rebuilt. Set in original steel frames with beautiful hardware patinated over time and use, the panes were bowing with many cracked joints and were no longer weather-tight. During treatment, old lead-based paint was removed from the frames, and the windows were rebuilt using the old glass, and set into new lead that matched the exact profile of the original. The completed panels were then puttied back into the restored frames, which had been newly painted while preserving the hardware.


Completely taking apart the windows in order to stabilize them also afforded the opportunity to seamlessly incorporate old work with new. The homeowner wanted to augment the original geometric design with a customized, hand-painted center crest in a classic medieval style.


Understanding the functionality of the windows plus the period design distinguished this project as best suited for preservation rather than repair. “Thank you, Ariana, for your and [Team Nzilani’s] work on this project. It is truly a thing of beauty.”


Detail of Tudor-style home with new heraldic shield (left & center). The window panel damage before preservation (right).


So, what is a homeowner to do who wants to make the best decisions for their windows and their health? First, ask lots of questions and request examples of previous work similar to your project. Is the company qualified and insured to remove, preserve, and install the windows by themselves? Or does some of the work have to be outsourced?


Ask contractors about their lead-safety plan. They should have a written document of each step undertaken to protect the client and workers for the entire project (on site and in the studio), including testing of employees' blood-lead levels (BLL) every 6 months, respirator fit tests, and ongoing training. At the time of this writing, the CDC recommends a BLL of 5µg/dL or lower for the public. Visit the United States Environmental Protection Agency site at for more information.


An improperly executed job will continue to be a headache if not an outright danger long after a contractor has moved on. But if you take the proper steps and work with professionals to protect yourself and your windows, you can literally breathe easy!

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and After


Ariana Makau is the president and principal conservator of Bay Area-based Nzilani Glass Conservation, Health and Safety Chair on the Board of the Stained Glass Association of America, and a Fellow of the American Institute for Conservation. Nzilani is an award-winning firm known for all facets of stained glass preservation and architectural art glass fabrication. Nzilani core values, “Be Safe. Have Fun. Do Excellent Work.” guide every project, including windows and domes for: private homes, churches, museums and monumental historic buildings. Nzilani focuses on self-empowerment through information: sharing processes, health and safety procedures (particularly lead awareness) and the importance of preserving cultural landscapes and the environment. Capable of completing a project “in-house” from start to finish, they also enjoy collaborating with other folks in the trade (GCs, architects, masons, carpenters and metalworkers, etc.).

For more information visit and follow @nzilani_glass on instagram

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