Our stained glass windows are bulging, sagging and bowing. Why is this?
A stained glass window consists of many individual pieces of glass held together by strips of lead caming. The average life of the window is usually 70 to 100 years. As the lead and putty decay, the entire structure of the window begins to weaken under its own weight. Expansion and contraction of the lead due to heat from poorly ventilated exterior protective coverings also contribute to the windows movement. The sagging and bowing are evidence of the final stages of this process.
If this problem is not addressed, the glass will crack or fall out of the caming until the window eventually collapses. However, proper restoration can extend the life of the stained glass window for up to another 100 years.
Our stained glass windows are between 70 and 100 years old.
What signs of deterioration should we look for?
When you inspect your windows, be sure to use a bright light and look for the following signs of decay:
- Sagging or bulging
- Cracked or missing glass
- Rattling or loose sound when stained glass is tapped
- Unattached reinforcement bars and/or broken solder joints
- Light, water or air leaks through the stained glass window
- Previous repairs, such as mismatched glass, silicone glue, or excessive addition of reinforcement bars
- Minute cracks in the lead (best seen with a flashlight and a magnifying glass)
Any one or more of these problems would indicate the need for maintenance or restoration of your stained glass windows.
What can we do to extend the life of our stained glass windows?
- The type of restoration of old stained glass windows depends on the level of deterioration. Options for restoration include:
- Preventative Maintenance: At least every 20 years, windows should be assessed and have general maintenance performed. This may include cleaning, removal and weatherproofing with putty, and documentation of their condition.
- In cases where the lead is still in good condition, but the stained glass is sagging or buckling, the windows may be removed, flattened, repaired and puttied.
- In cases where the lead has decayed, stained glass windows will not sustain this type of repair, a complete restoration including re-leading may be necessary. Re-leading and restoration is the most thorough and cost effective option. It will return the window to its original strength and condition, extending the life for another 100 years.
- Exterior glazing or covering of stained glass windows is also an option to prevent deterioration to a stained glass window. Exterior glazing includes installing a panel of clear glass over the exterior of the stained glass.
Is stained glass window restoration cost effective?
Unlike major building repairs, such as roofing and plumbing, stained glass repair or restoration does not have to be done all at once. A maintenance program can be spread over a period of years. But by putting off maintenance, stained glass windows continue to deteriorate, making repairs more costly overall.
If you consider that a restoration can extend the life of the stained glass window for another 100 years, the investment is more cost effective than most major building repairs.
What is the process of designing new stained glass windows?
The general process for completing a successful stained glass project:
- Initial discussions regarding themes, plans and desired results
- Determination of preferred style and artist
- Receive estimate from Cambria Glass & Insulation
- Review stained glass and artist’s expertise and abilities based on our overall body of work
- Approve studio and artist, agree to terms, and sign contract
- More discussions with artist regarding themes and desires
- Artist submits renderings for approval or revision until client is satisfied
- Fabrication of windows
- Final installation