Roof Space detectors

["Paul" <someones-father-@xxxxxxxxxxx>]

Just trying to get some input on different ways that techs can protect the
roof space.

We look after a chain of HiFi shop which are high risk.
Roof entry is quite a common way of gaining access. We can easily protect
the shop itself but the roof space is quite hard. Its about 2 metres from
ceiling tile to tin roof, with lots of airconditioning ducts up there so not
a great deal of range would be achieved from each device.

Any suggestions

Paul