How do possums and rats gain access onto the roof?

Trees and vines that overhang a roof need to be cut back from the roof line by at least two metres. This will stop the possums and rats jumping the distance to the roof. Electricity and telephone cables that lead from the street to the house can also allow access onto the roof. Tubing and or a disc needs to be placed on these wires. This will need to be done by a qualified electrical trades person.