To tell if your windows are in need of restoration, an initial assessment can be made by your architect or the stewards of your building.  If any of the following signs are present, it is a good idea to have your windows inspected by a professional.  


Do you see signs of deflection or buckling?  Over time your building may have settled, or possibly there was never a proper support system in place.  The lead in your windows may be fatigued.  Look to see if any support bars or copper wires have become detached.  Look for cracked glass, which is often the result of stresses caused by deflection. 

Can you see daylight through gaps in the window?  This can be caused by lead fatigue and deterioration over time.  

Is water penetrating through your window?  This is an indication that the original waterproofing compound has dried out and fallen from under the lead. Moisture is detrimental to the painted surfaces of the glass, and if not rectified, can cause irreversible damage to the window.

If your windows exhibit any of these signs, some level of conservation may be required.  If problems are ignored, the window fabric will continue to deteriorate and deflection may advance, causing more glass to crack or break. Once a stained glass window reaches this state, it should be closely inspected by a professional.  If restoration is postponed, it will become more time-consuming and costly to correct. 

A word of caution however: Be mindful that just because a window exhibits any one of these signs, it is not a clear indication that full releading is needed. There are means and measures that can be taken to stabilize and maintain the condition of a window until complete releading is truly necessary.  Be aware of the common, but false statement used by many salespeople that “After 100 years, your windows must be completely re-leaded or they will collapse”.

Make sure that your windows are closely inspected by an actual hands-on conservator, not a salesperson.  

Ask questions such as: 

Why do my windows need to be completely releaded?

What evidence do you have? (If the person inspecting your windows, truly inspected them up close, they must be able to provide you with detailed photos the areas exhibiting lead fatigue and deterioration).

Tell me about the Corpus Vitrearum Medii Aevi (CVMA) code of ethics and guidelines.   What does it say?

Do you follow and abide by it?

Are you familiar with the Institute of Conservation (ICON) code of ethics and guidelines?
What does it say?

Your windows are a part of history. They are artifacts and as such they must be cared for properly, maintained; Its fabric preserved and conserved for as long as possible. Complete releading must be the last resort. It is a time consuming and possibly a daunting task, but one well worth educating yourself about. Get to know the history of your windows, but more importantly, get to know who you are trusting with their care.

When is it time to restore your windows?