Stained Glass Preservation

Antique stained glass panel large Antique stained glass panel large

Preserve & Protect Your Stained Glass

Proper care and maintenance should be taken to protect and preserve your stained glass!

Periodic Inspections

It is good practice to periodically inspect windows and address any concerns in the early stages. The longer you leave the repairs the more likely the deterioration will continue and then you are left with increased repair costs. Taking a photographic inventory of your windows periodically so that you have a visual record of any changes is recommended. When assessing windows, look for the following:

  • Broken/cracked pieces of glass or pieces that appear to have slipped
  • Excessive bowing (more than 1” out of plane)
  • Broken tie wires on metal support bars that are in place to support the window
  • Rattling of the stained glass
  • Condensation on the stained glass or in-between secondary glazing

Proper Cleaning

Cleaning should always be carried out by a professional. Ionized water (regular tap water) damages the glass, so conservators must use a pH neutral cleaner. Clean very gently, vacuum very lightly…every five to ten years if the windows are accessible.” Higher windows that require expensive scaffolding to reach can be cleaned every 20 years or so.  If the windows have paint details, the stability of the paint should be assessed before cleaning; some are too fragile for any form of cleanser. Windows that are too delicate to be cleaned have two options: repainting or conservation.

Protective Glazing

Protective glazing greatly extends the life of stained glass windows by protecting them from projectiles and direct rain and wind. It is important that protective glazing be adequately vented to allow air circulation and be easily removable for future cleaning or restoration. Shoddy workmanship can cause more damage to the glass than it would have acquired without glazing.


The lifespan of lead depends on the surrounding environment, but eventually it will have to be replaced.  Tell-tale signs of a window in need of re-leading include bowing, buckling or sagging panels, tie wires loose from the structural support bars and significant movement of the window when pressed. In most cases, all lead should be replaced as oxidation and age (generally over 60 years) will lead to further degradation of the structure.