My, my, we're still talking about laminated and tempered glass! I find the
technical info very interesting, david. Your comment about the problems
when laminated layers break down makes me think of what happens in old car
windows, which first showed up in the 1930s cars as these reached the 25-30
year mark. The plastic center layer of the safety glass would begin to turn
cloudy. I think this was due to air reaching it as the sealed edges broke
down. Nothing for it but to replace all the glass, not cheap in a typical
6-light sedan which would have a total of as many as 14 separate pieces of
glass. Better in the days when all this glass was flat, but more expensive
in the later cars with curved glass. Is this the same problem you are
describing on buildings? 

Don White