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Subject: Stained glass

Stained glass

From: Lorraine Schnabel <rainyroon>
Date: Wednesday, July 11, 2007
J. Bryan Blundell <jbb [at] prginc__com> writes

>Lorraine Schnabel <rainyroon [at] verizon__net> writes
>
>>...
>>I would also urge you to avoid epoxy repairs to the wood wherever
>>possible. ...
>>... Regardless, my personal opinion is that wood window sills
>>should never be repaired with epoxy.
>
>I can understand this statement from the point of view of the
>history of some epoxy repairs. However, I view most of these problem
>epoxy repairs as cases where the repair process did not understand
>and take into account the original cause of the problem, as well as
>the on-going existing conditions/environment. ...
>...
>I would hope that we view materials and techniques as appropriate or
>not appropriate in relation to a specific application and not
>wholesale statements based on poor understanding, bad specs and/or
>less than knowledgeable workmanship. This mean the people making the
>choices need to deal with the whole picture and not just
>generalizations.

My comments regarding epoxy repair of wood are based on my practice,
my experience, and research I have done. It goes without saying that
each project must be evaluated on its own merits, and that the root
cause of observed deterioration must be determined before any
treatment decisions are made--these are basic tenets of
conservation.

I work on large buildings. Most of these buildings are on a 20-30
(or more) year maintenance cycle for anything that cannot be easily
reached by a ladder. A great number of them have been churches. My
practice, therefore, has taught me to seek out repairs that are
self-sustaining, and in particular to look for repairs that do not
require maintenance of intact paint films or sound joint filling
materials to retain their integrity. Unfortunately, based on
observations of previous repairs, conversations with numerous
carpenters, and research published by the Forest Products Laboratory
in the Journal of Coatings Technology (March, 2000) I do not believe
that epoxy repair of window sills fall into this category. The most
self-sustaining repairs I have observed in my years of practice are
those which utilize materials similar to the original (dutchman
repairs), rather than materials with completely different physical
and chemical properties.

I would agree with the statement that buildings and their materials
are often not given due respect. However, unlike the materials
inside the buildings, building materials have work to do. If they
cannot perform that work any longer, then they need to be repaired
or replaced with materials that can--a building is a system that
depends upon the functional integrity of all its parts if it is to
survive the elements. Building materials that retain important
information can be salvaged and kept for study (consider the
Architectural Study Collection at Independence Hall National
Historic Park)--they should not be kept on a building if they no
longer can perform the function for which they were originally
intended.

I think I understand the issues quite well. I was, perhaps, mistaken
to not more clearly lay out my rationale for the statements I made
in my original response.

Lorraine Schnabel
Architectural Conservator
110 Kensington Avenue
Trenton, NJ  08168
609-394-7877


                                  ***
                  Conservation DistList Instance 21:17
                  Distributed: Saturday, July 21, 2007
                       Message Id: cdl-21-17-008
                                  ***
Received on Wednesday, 11 July, 2007

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