s a long-time metal roofer, I was
always skeptical about flat roofs. I
had an attitude change about
low-slope applications, though,
when I started using modified bitumen roofing
a few years back.
Commonly referred to as “torchdown,”
thermally fused single-ply
asphalt bitumen membrane was
developed in Italy during the mid-
1960s as a lining for underground
fuel and water tanks. Roofing was
a logical next step, and torchapplied
roofing systems began
to be installed in Italy in the
1970s. Because rooftop conditions
are much harsher
than those underground,
however, those early
systems often failed
by Rick Palmer
A prematurely. The addition of specially
formulated polymers gave the original
membrane much better resistance to
heat, cold, and UV, as well as improved
elasticity, which is why