For internal renovations, basic things like hacking walls, changing tiles, etc... does not require council approval.

If you're rerouting the sewerage and water piping in your home, more often than not you are required to submit plans for approval especially if there is significant movement of the pipes, especially the water main.

Movement or modification to structural features, such as weight transfers or modification of roof design must get approval and have accompanied technical drawings for submission.

But the one thing you must never forget is.... if you've got a tong outside your house for rubbish you confirm need the approval for placing the tong by the roadside. If don't have confirm saman.

Hope that helps.