Many stained glass windows suffer bulging, cracking and leaking.  Over the years, the putty and/or sealant that surround the panels absorb moisture and then harden and crack.  Sometimes the deteriorated putty falls out, or on occasion, restricts the normal expansion and contraction properties of the panels.  In rare instances, the lead came surrounding each individual piece of glass must be replaced.  If lead came is flaking away, or was stretched thin during construction, then the window may require removal and re-caming.  But great care and evaluation should be afforded before making this decision.  This is a highly oversold and labor intensive option which can be very lucrative to reconstruction studios…regardless of necessity.  Stained glass panels can normally be re-grouted and restored in place.
 
As rare as the occurrence is, lead came does fail…
 
While restoring the stained glass panels in the Chapel at the U.S. Military Academy, we found that the lead came had badly deteriorated…probably from prolonged exposure to the polluted damp atmosphere coming off the Hudson River, and mixing with the warm moist air inside the stained glass panels.  The hardened, cracked and loose putty around each stained glass panel had completely failed, thus soaking the panels with sulfite laden air.  Each window, containing over sixty-four panels was removed from the stone tracery and meticulously re-camed in the Waters Craftsmen studio.
 
But, even more dangerous than a harsh environment, are the ills churches and their caretakers suffer from persuasive salesmen, pushing plastic protective covering or re-caming scams.  Too many salesmen use fear as a tactic to scare unsuspecting clients into contracting expensive unwarranted lead came replacements, or plastic window coverings.
 
Waters Craftsmen has removed thousands of dollars of polycarbonate Lexan covering, only to reveal poorly maintained stained glass windows.  Expansion and contraction rates and ranges of polycarbonate plastic covering are greater than glass, and if set too snug, will crack stone and brick window frames, pull loose from joint sealants, and leak.  And based on my experience, the installers seldom educate historic property owners about the required tasks needed for normal glass/frame maintenance, but instead, focus on selling cheap, easily installed plastic coverings.  If window protection is a priority, then please consider an appropriate grade of glass protective covering, and/or better security.  Most coverings are a retro fit at best, and if not done in conjunction with proper maintenance and great skill, will result in future intrusive, expensive restoration.