Ken Follett wrote:

>
>
> Rarely. EPDM, the large sheet of rubber type of roof either with our without
> ballast. Ballast to keep the balloon from getting sucked off the roof.
> Unprotected EPDM is subject to punctures.

You forgot that  uncoated EPDM roofs are sometimes subject to
seagull preditation-
the supposition is that they take the membrane for a whale & figure That soups
on.

DD