On Feb 17, 1:45 pm, "SoCal" wrote:
A friend of my mine owns a century old victorian that still has much of the
original glass. The glass has actually sagged so the bottom is thicker than
the top. She feels that the they have historical value and doesn't want to
tamper too much with the house ...

While a common belief, it's almost certainly not true that the
thickness difference at the bottom is owing to glass "sagging" from
age...see the following

http://www.sciencenews.org/pages/sn_...30_98/fob3.htm

That piece of trivia aside, I commend the thought of not desecrating a
possibly historic house both from the possible financial ramifications
but moreso even from the simply "it's the right thing" to do
standpoint.

I'd investigate what is apropos for the specific area and house and go
that route. As someone else noted, external storms are certainly not
unheard of. If the house is in a conservation district, they
undoubtedly have guidelines -- if not, restricted, even so it is
likely they will be happy to point you in reasonable directions.