Historic Stained Glass Restoration for Churches and Institutions

Cooper O'Neil Stained Glass is a Philadelphia-based conservation studio with a 12-year record of historic window restoration for congregations, academic institutions, and landmark buildings across the region.

🏆 2024 Preservation Award Recipient - The Preservation Alliance of Philadelphia

Your windows are part of your building's history and your organization's identity. When they begin to fail the question isn't whether to act but how to act wisely. We help building committees and facility managers understand exactly what their windows need, what it will cost, and how to plan for it.

No cost. No obligation. A written report your committee can use.

Stained glass doesn't fail all at once.

Deterioration is slow and easy to defer, until it isn't. Leads oxidize and weaken over decades. Panels begin to bow under their own weight. Joints open up, and water follows. By the time you notice something is wrong the underlying damage is often years old and significantly more expensive to address than it would have been earlier.

Building committees face a particular challenge: the windows are irreplaceable, the budget is finite, and the decision carries weight far beyond a typical maintenance call. Getting it right means understanding exactly what you have, what it will cost to preserve it, and how to sequence the work responsibly over time.

That's precisely what we help you do.

What Working With Us Looks Like

We've designed our process specifically for congregations and institutions — with clear documentation at every stage so your committee always has what it needs to make informed decisions.

Step 1: Condition Assessment
We visit your site, examine each window, and document their condition in detail. You receive a written condition report — at no charge — that your committee can use for budget planning, board presentations, and grant applications. This report is yours regardless of whether you choose to work with us.

Step 2: Scope & Proposal
Based on the condition report, we develop a phased restoration plan with clear, itemized pricing. We prioritize by urgency so you can address the most critical needs first and plan subsequent phases around your budget cycle and fundraising calendar.

Step 3: Conservation Work
Your windows are carefully removed and transported to our Philadelphia studio, where they are restored using traditional techniques and period-appropriate materials. You receive photographic documentation throughout the process — both for your records and for use in donor communications or congregational updates.

Step 4: Reinstallation & Warranty
Restored panels are reinstalled with care. All restoration work carries a warranty.

We've completed this process for congregations and institutions across the region. Here's what that work has looked like in practice.

The Unitarian Society of Germantown, Philadelphia, PA
Full Conservation of Original Heaton, Butler & Bayne Windows, c. 1890

The Unitarian Society of Germantown came to us with an original windows by the renowned Victorian firm Heaton, Butler & Bayne - some of the finest examples of late 19th-century ecclesiastical glass in Philadelphia. After more than a century of service, the windows had reached a critical threshold: leads were failing, panels were bowing, and the risk of irreversible loss was real.

We completed a full conservation of all thirteen portions of the window, including lead replacement, glass repairs, and weatherproofing. The restored windows are now structurally sound and expected to remain stable for decades without further intervention.

The Alumni Chapel, The Hill School, Pottstown, PA
Historic Restoration of Original Chapel Windows

The Hill School's Alumni Chapel presented a scope familiar to many historic institutional buildings: a collection of windows installed across different periods, in varying states of condition, requiring a unified conservation approach that could be phased to align with the school's budget and calendar.

We completed historic restoration of 23 of the chapel's existing windows, including removal from openings, re-leading each panel, repairing damaged glass, adding new dedication plates where needed, and reinstallation on site. Working within an active school environment, we scheduled removal and reinstallation to minimize disruption to chapel services and school events.

The Memorial Room, The Hill School, Pottstown, PA
Historic Restoration of Original Library Windows

These original Connick and Associates windows were damaged by an improperly installed exterior storm window layer. A lexan exterior glazing had been installed but not properly vented. The school took action to replace the exterior glazing, but the underlying damage to the stained glass caused the windows to bulge and bow- risking long term damage to the glass and frames.

We removed and re-leaded these panels, catching the issue before glass could break and original detail was lost permanently. This project was completed in phases during summer break for the school.

First Presbyterian Church of Bridgeport, Bridgeport, PA
Full Restoration of Original Front Facade Windows, c. 1900

The front facade windows of First Presbyterian Church of Bridgeport are a striking expression of the building's historic character - and after more than 120 years, they required comprehensive attention. Panels were loose in their frames and were becoming hazardous. The congregation made the decision to restore rather than replace, preserving the original glass and its irreplaceable historical integrity.

We completed a full restoration of 21 facade window sections, including removing, re-leading, and re-weatherproofing these windows. Restoring the windows solved the safety concerns and preserved a unique light in the church vestibule.

The First Step

A written condition assessment is the most useful thing a building committee or manager can have before making any decisions about historic stained glass. It gives you an honest picture of what your windows need, a clear framework for prioritizing and budgeting the work, and a professional document you can bring to your board, your donors, and any grant applications you pursue.

We provide this assessment at no charge, with no obligation to proceed.

Fill out the form below and we'll be in touch within one business day to schedule a site visit.