Roofing and pest control

Mary Baughman inquires about the possibility that crickets, bats,
and other pests are entering the upper floors through an expansion
joint in her institution's flat roof.

I am, however, a little confused concerning the nature of the
"expansion joint" on the building. Typically expansion joints, which
are really just separations between building elements to minimize
the effects of movement and other stresses, are fully enclosed to
prevent water (or insect) penetration. The NRCA Handbook of
Accepted Roofing Knowledge provides an example of a common expansion
joint which includes abutting curbs (minimally 8-inches above the
roof deck), compressible insulation, and flashing. Loss of, or gaps
in, the insulation could allow pests to move from the roof system to
the roof deck, but there would then have to be an avenue from the
roof deck into the building (in other words there is rarely a
straight path).

Looking at the problem from the perspective of the pest, rather than
the roof, still leaves some questions. While there are a number of
winged crickets (such as the house cricket and the mole cricket),
they are usually attracted to lights at night. Are there lights or
other attractants on the roof? Is it possible that while the roof
was the original route, there are now breeding colonies finding
harborage? Have gridded sticky traps helped to narrow down the
infestations? Has the species been identified (for example, camel
crickets are not only wingless but are also likely to be attracted
to moist areas)?

This sounds like a good case for a preservation assessment focusing
on the roof and also on the pest problem. Hope at least some of
these ideas are helpful. Best wishes,

Mike Trinkley, Ph.D.
Chicora Foundation, Inc.
PO Box 8664
Columbia, SC  29202-8664
803-787-6910

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                  Conservation DistList Instance 9:14
                   Distributed: Friday, July 28, 1995
                        Message Id: cdl-9-14-006
                                  ***