Maintenance, Repair, Restoration and the slow aging of panels.

Many of the stained glass windows in our communities have begun their second century of service and are now in need of periodic maintenance, repair or restoration to assure their continued service for generations to come.

By the very nature of the materials involved, stained glass windows are expected to provide long years of service between periods of maintenance. While there are many conditions that influence just how much time can ellapse between maintenance calls it is not uncommon for 40 – 80 years to pass before some neccessary work is required. Some of the factors that play upon these windows include; the size and location of the windows, gravity, thermal expansion and contraction caused by sunlight, wind load, condensation or atmospheric pollutants, etc. As well, the style or type of design and the materials used to manufacture the panels are also some of the considerations affecting the aging process of these windows.

As time goes by often all that is needed is a little periodic maintenance to keep these heritage windows in good repair. The re-setting of a panel, tightening of the tie wires, the repair of broken pieces of glass or the application of some glazing compound are some examples of basic maintenance. Ventilator panels needing a little attention or adjustment to see them smoothly operational again are another example. These little maintenance tasks can most often be dealt with on-site without the cost of removing the panels from the frames or disruption to the congregation or property owner.
Sometimes the work needed requires a little more involvement. A bulged or buckled window that is getting extreme enough it might damage the glass needs attention. Loose panels in need of cementing, glass that is becoming un-housed from the lead, that are beginning to fail and no longer provide adequate support for the leaded panels are examples of windows needing immediate action and repair. As well, it is inevitable that stained glass windows eventually will require re-leading to replace fatigued, oxidized or overly stretched leads. Most of these conditions, cited here, will require the removal of the window panels to a studio for the work to be performed properly.

In the most extreme cases restoration may be required to save or return heritage stained glass panels to full service and former glory. Damage caused by vandalism, fire, poor adhesion of painted details, excessive amounts of broken glass or prolonged neglect of maintenance and repair can all eventually contribute to a situation that requires careful restorative proceedures to successfully complete the work.

Some additional considerations involved with the repair and maintenance of stained glass moves beyond the actual leaded glass panels themselves. The conditions of the window frames, sills or tracery, as well as the existence of protective storm glazing over the windows, need to be taken into account as these three elements are so linked together that work performed on one most often affects the others.

Because stained glass ages so slowly, and often its beauty is seen from a distance, it is easy to understand how maintenance might become lapsed, or overlooked, by a succession of changing committees and caretakers throughout the years. As decades pass it can become increasingly difficult to establish a reference point from which to judge the current conditions of stained glass windows, surrounding woodwork, protective storm glazing, and in knowing when it is time to seek the help of a professional studio.

To this point please refer to this checklist to assist in determining the need for maintenance or repair to your stained glass, woodwork or protective storm glazing.

All of these and more are considerations for keeping stained glass serviceable. By evaluating the current conditions it becomes possible to catch up with overdue maintenance and repairs. Establishing records and dealing with the issues of periodic maintenance is, in our opinion, by far the best practice. The costs are more manageable and the intrusion to perform the work upon the church and its congregation is greatly reduced.

If you should have any questions, or would like to have your windows inspected, please contact the studio and we can assist your organisation in achieving its needs in developing a maintenance program that is focused, practical and achievable.

Neil Hanscomb


Stained Glass Checklist

  • Broken, shattered or missing glass- more than just the occasional piece here and there
  • Bulges or buckling of the panels- more than just a slight deviation from plumb*
  • Broken, torn or extremely corroded leads*
  • Loose and rattling glass pieces
  • Visible daylight between glass pieces and lead
  • Loose and rattling panels
  • Visible daylight along perimeter of panels and woodwork or between stacked panel slip-joints
  • Bent, twisted or dis-associated support bars or armatures*
  • Unstable painted glass elements
  • Ill fitted or roughly operating ventilating frames

* these items are best inspected using reflective light e.g. spot light, torch or trouble light

  • visible-daylight1

    visible daylight

  • unstable1

    unstable paint on glass




Protective Glazing Checklist

  • Broken or missing protective glazing
  • Unvented protective glazing
  • Protective glazing in direct contact with the leaded glass panels
  • Condensation developing between the glass surfaces
  • Leaky flashing or visible signs of water penetration between ventilator frames and protective glazing
  • Obvious signs of water penetration, mildew, molds between the glass surfaces
  • Debris filled protective glazing along sills
  • unvented protective

    unvented protective

  • condensation


  • leaky flashing

    leaky flashing

  • ventilator


  • debris filled

    debris filled

Sills, Sashes and Tracery Checklist

  • Obvious signs of decay or previous repairs to woodwork along sills and flat areas of tracery
  • Soft, punky or spongy areas
  • Missing sealants and compounds allowing water penetration into woodwork
  • Wood filler that is swollen, kicking or missing on sills and flat areas of tracery
  • Staining or visible signs of movement along joints and sills, muntins and mullions
  • joint movement

    joint movement