Re: how do i attach a metal framed cat run to a hardy plank wall
Welcome to the Bunnings Workshop community @geordie. It's wonderful that you've joined us and many thanks for your question.
It's always best to locate the timber studs behind the Hardieplank and screw directly into them. They'll be able to support far more weight than the planks themselves. Sometimes the studs are given away by a vertical row of nails down the planks. Alternatively, you might like to invest in a stud finder to make the job easier.
If you can show us an image of the cat run and the fixing locations, I trust our helpful members will have further advice for you.