"Martin Sykes" wrote in message
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7. You say it is covered in gravel so maybe it was originally designed as
a
patio area. Maybe you should ask the original builder if it has been
strengthened for use as such?

Gravel is a common flat roof covering. It is there to protect the felt from
sunlight and, as the stones should be rounded, to minimise the risk of it
being punctured when people walk on the roof. It is, however, only intended
for occasional access, not for regular use.

Colin Bignell