1

In 1964 the amount of built-up roofing com-
ponents produced was sufficient to cover over 1.7
billion square feet of roof area at an installed cost
in excess of 450 million dollars. A large number of
roofing systems constructed from these compo-
nents should perform adequately for 20 or more
years. However, the small percentage which are
destined to fail prematurely will present serious
and costly problems to manufacturers who pro-
duce the components of the system, the architects
who design the systems, the contractors who apply
them, and the building owners and occupants who
expect good service from them.

In the design and construction of a roofing

system, the architect and roofing contractor have

little choice. They must rely either on their past

experience with the performance of a specific sys-

1 Also published as part of ASTM STP 409, American Society for Testing

and Materials (1966).

1233 55

5

tem under known exposure conditions or
material and application specifications
mended by manufacturers. In order to
greater flexibility, there is a need for desi
teria by which the architect-engineer and
rials manufacturer can select suitable ma
to assure a properly designed roofing system
will perform adequately under specific ex
conditions.

The performance of a roofing system car
predicted or evaluated entirely on the basis
properties of the individual components. An
standing of the interdependence and inte

between and among components is of pars

importance and must be considered by

signer. This is apparent from the discussi

various authors, of problems such as blis

wrinkle cracking, and membrane shrinkag