Backing Plates add substantial strength and prevent damage and safety hazards in situations where there is an absence of solid mounting surface. Backing plates serve the purpose of distributing load from a single point of pressure to a wide area and increasing holding strength and rigidity substantially by using the strength of all fasteners against a single point of pressure.
When backing plates should be used:
If the depth of the mounting surface is less than the length of the recommended fastener a backing plate should be used and the fasteners should be switched to machine screws with proper washers and nuts.
If it is known that substantial force will be exerted on a component it is best to mount using a backing plate.
If there is regulation, specification or previous use showing use of a backing plate replacement should be done using a backing plate.