Your Questions Answered

Q: Why do we need to undertake restoration of our windows?
A: Two main reasons: the lead used in windows during the early to middle twentieth century was very pure and soft. It deteriorates within about 70 years. Harder lead alloys, like those used in the Middle Ages that contained additional metals like tin and silver, typically endured for at least a century. But even medieval windows have been releaded numerous times. Second, the installation in the early 1980s of protective glazing— though common at that time— has accelerated the deterioration of the lead by trapping heat and moisture.

Q: OK, but why do we need to do it now?
A: As part of the Parish master building and maintenance plan, I’ve been monitoring the state of Saint Thomas Church’s windows for five years. Even during that time, the deterioration has been marked—sagging and bowing of the panels in some cases leading to cracking and breaking of glass. The longer you wait to begin the work, the greater the chance of substantial damage and the higher the cost of restoration.

Q: Some of these windows have been in place less than 40 years— how long will the repairs last? A: Today we understand more about the aging of materials, so we will be using a lead came of a stronger alloy than was originally used. This should last at least 100 years.

Q: How does this project’s scale compare to others you’ve worked on or studied? A: With 8,600 square feet of glass, almost 500,000 pieces of glass, and 12 conservation studios, this will be the largest complex stained glass window restoration project ever undertaken in the United States.