UV filtering materials

Betty L. Seifert <seifert [at] dhcd__state__md__us> writes

>A colleague serving on the board for a historic house asked about
>using UV film to cover interior window glass.
>
>   "Film to cover the windows was purchased, but a tinting company
>    informed us that placing film on the interior window surfaces
>    would cause heat build up and wood deterioration in the frames
>    between the inner window and outer storm window. (The museum is
>    in a circa 1925 house). Would this happen? They propose to
>    provide protection on the storm windows at much higher cost"
>
>Does anyone else have experience with this?  The local firm wants to
>charge a high fee for the installation of their product.

The problems associated with your use of UV film on interior storm
windows has a flip side to the coin. It is normal for a commercial
firm to try and sell their products in the strongest argument
possible just as a suitor might seek marriage...that doesn't mean it
is wise to marry the man. I think a legal term covers the sales
pitch: Res Ipsa Locquiter [The thing speaks for itself]!

The other side of the coin from a conservation point is that windows
that do not have a dead air space between them and a storm window
are prone to moisture condensation and the resultant lose of paint
and substrate deterioration be it wood or metal. To add a UV
filtering film in such a situation would do little or nothing to
change the micro-environment between the outer storm window and the
window. Normal architectural practice is to vent the storm window at
their bottoms with a couple of small holes so that any moisture
inside the dead air space can escape. Exterior painted surfaces
should be looked at as "sacrificial finishes" anyway as paint films
subjected outside to direct sunlight will have daily extensive major
"thermal shock" as temperatures and sunlight change during the day.
Put your money into routine maintenance which the windows will need
anyway.

Rather than buy the expensive product, why not benefit the museum
and buy stock in the company that is selling it. Good luck,

Richard O. Byrne
Staunton, Virginia
USA


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                  Conservation DistList Instance 17:33
                 Distributed: Tuesday, October 7, 2003
                       Message Id: cdl-17-33-001
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