Vapor barriers

We are in the process of renovating an old department store to serve
as a new museum.  It is an 80,000 sq. ft. building and it will be
multi-tenant We will be occupying approximately 15,000 sq. ft. on
the third and fourth floors. Approximately 11,500 sq. ft. will be on
the third floor and 3,500 sq. ft. will be on the fourth floor (to be
developed later).  There will be a 16'x30' cut- out between the
third and fourth floors (currently scheduled to be sealed until
fourth floor development). There will be a rubber roof. The exterior
walls are brick. The architects plan to attach metal studs to the
brick walls, place rigid foam insulation between the studs, and
screw drywall onto the studs.

We would like to place a vapor barrier behind the drywall to help
retain winter humidification in our space.  I'm looking for
suggestions concerning vapor barriers, keeping in mind that the
barrier will be punctured by screws and that we are on a very tight
budget. Finally, after months of saying that we didn't have the
money for a vapor barrier, the architects now say if we want a vapor
barrier to let them know what we want ASAP.  Consequently, I'm
scrambling for information that I should have been accumulating
months ago.  Could you please post directly to me as well as to the
list in case I need the info before the digest arrives? Thanks.

Michael Knies
Collections Manager/Archivist
Canal Museum, Easton PA

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                  Conservation DistList Instance 9:24
                Distributed: Saturday, September 9, 1995
                        Message Id: cdl-9-24-008
                                  ***