Colourbond is steel coated in zinc and aluminium then painted . The soil will corrode the base steel eventually , time taken will depend on the depth of scratches in the 2 coatings . The point of the worst corrosion is at the surface of the soil were moisture and oxygen are at the best combination . Chemical Engineers please step in here .
Isolating the fencing material as much as possible from the corrosive elements , the dirt and water , will prolong the fence life . Cheap solution , polyethene sheeting , that shit they lay under concrete slabs as a moisture barrier .
As for deforming the line of the fence , step in Mech and Civil engineers , no chance of a Civil eng as they dont have enough personality to ride a motorcycle let alone a Kawa or a 2t , whatever , there wont be much force on the fence if you dont compact the soil too much . The more force you put down into the soil , the more you will put out against the fence . But this wont help the plants , if the soil is packed in really hard .
Me , would slip some black poly sheeting in and fill with nice mulched soil and plant away .( if you dont deform the line of the fence with weight of the soil there wont be a long term problem) Plants that grow up really big will do more damage to the fence .
When is the back yard BBQ ?
