Restoration and Repair

Restoration is “an act of restoring or the condition of being restored” and “a bringing back to a former position or condition”. (Source – Webster’s online dictionary).

I’ve listed the definition for restoration at the top of this page because I believe an educated consumer makes a better customer. To that end, it is important to note that there is currently a schism among stained glass studios regarding the word “restoration”. The first group uses the word to encompass general maintenance and procedures that generally fall under “repair”. The second group, to which I feel I belong, classifies "restoration" as a much higher standard than either a "repair" or "relead" falls into.

What is best for a particular window should be decided upon after taking all of the window's circumstances into account, which can include anything from location, to lead composition, to historic significance, to sentimental value, to amount of weather the window receives, etc.


Includes minor fixes such as the gluing or replacing of a small number of pieces, re-leading a small section of the window, etc. Sometimes repairs can even be done onsite.


Re-leading (in my opinion) is routine maintenance that needs to be done every once in a great while. Lead (the metal that encases the glass edges) eventually gets fatigued and starts to slump and droop out of place. Although the general rule of thumb is roughly every hundred years or so, environmental factors have a huge impact on this number. The composition of the lead, the size of the pieces of glass, the overall design, the location of the window, the thickness of the lead, the structural supports used… All of these things contribute to the overall lifespan of the lead used. I have re-leaded things as young as 25 years and as old as 130 years. It all depends on what kind of stress the lead has been subjected to.

While care should be taken to utilize the same types of lead that are in the original window – I prefer to take a rubbing of the window before dismantling, and label each lead with profile and width - there are exceptions to this rule: Windows made during World War I or World War II oftentimes utilize lead that is really too narrow for the pieces of glass they encase, lead being a scarcity during war time. Cases like this are rare, and are discussed prior to removal with the owner of the window.


It’s a tough word to define when dealing with stained glass because a lot of times, repairs and re-leads take place whilst a window is “ being restored”. The difference is the level of intervention, and the care taken to preserve historical accuracy, all of which makes defining restoration rather subjective.

I’ve listed a few of the thing I look for in a window that needs some TLC below – some I ran into in my previous job working for a large liturgical stained glass company. Other questions are pro forma in the industry when considering a restoration.

First, how important are the windows? A window that is historically significant, either to the local community as a whole, the window’s owner, or the arts world in general is a likely candidate for a higher level of restoration than a stained glass window that simply keeps out the elements in an older home. What is the level of intervention dictated by the window? Are there a lot of broken pieces that cannot be color-matched? Are there pieces missing? Was the window made too large for its existing space, and is that contributing to the failure of the lead? Was the original window built in very large sections? What environment will the window be placed back into? Will the window be in a high-crime area where protective glazing is a must? Will the window be subjected to extreme heat or cold?

Therefore, the basic elements involved have typical solutions, and they’re listed in order: The first option would be indicative of a high level of restoration – utilized for windows of historic significance, such as a Tiffany window. Each option after that denotes a lesser level of restoration.

Broken Glass (1) Glue, foil, or silicone edge-glue broken pieces so that all the original glass is saved. Replace only missing sections with as good of a match as can be obtained. Glass may have to be specially made to match. (2) Replace only smashed or missing sections with a good match. (3) Replace entire broken piece with a good match.

Painted Glass (1) Consult an expert on the deterioration of glass. (2) Reverse-paint the glass. (Re-firing glass that is old can sometimes has unexpected and irreversible consequences.) Reverse-paint missing sections on clear glass and leave a small space in between the original piece and the new paint, so they do not rub together. (3) For a window of no significance, a new piece can be painted, provided that a good glass match is found.

Lead (1) Melt down the old lead and re-mill it for use in the window. (2) Test the old lead, and buy new lead that is close in composition to re-lead the window with. (3) Re-lead the old window with the lead that the studio has on hand, making sure to maintain all widths and profiles of the original. (4) Occasionally, for a window of no note, the lead utilized is narrower than should be – either the pieces are very big and the lead is very narrow, or the window was made when lead was scarce, so the glazier used a very narrow lead because it’s what was available, or the glazier overstretched the lead… In cases like these, if it will visually “correct” the window, slightly larger lead can be used without severely affecting the overall look of the window.

Window Size (1) Maintain original glass and size. (2) Divide overlarge sections into smaller sections as dictated by the design or subject matter. (Any section that is larger than 12 square feet or 14 lineal feet is typically considered overlarge. Square feet = length x height, lineal feet = length + length + height + height.) Or for windows that were simply built too snug, trim border glass.

Documentation (1) Take detailed archival photographs prior to removal, and give to owner/steward to be stored offsite in case of fire. Take rubbings of each window on archival paper, notating cracked pieces, pieces that have been replaced with mismatched glass, lead sizes and profiles, and locations of structural bars or wire ties. Take detailed archival photos of all processes, including disassembly, unusual lead profiles, non-original pieces, etc. Take detailed archival photos post-installation. Give all rubbings to the owner/steward to be stored offsite in case of fire. (2) Take photographs of windows to be stored offsite for insurance purposes. Make rubbings of each window, notating lead sizes and profiles, and locations of structural bars. (3) Make rubbings of each window, notating lead sizes and profiles, and locations of structural bars.

For further information, the Census of Stained Glass Windows in America has published a wonderful booklet on the conservation and restoration of stained glass. It can be downloaded as a pdf file from: (PDF) Conservation and Restoration of Stained Glass: An Owner’s Guide

Other good publications on restoration include: The Preservation and Repair of Historic Stained and Leaded Glass