Dealing with "unauthorised" repairs is one of the most complex and challenging problems for any owner or strata managing agent. Some brief examples follow:

• A well intentioned owner has previously carried out at some stage bathroom repairs which have now failed. There is no evidence that permission was granted to carry out the repairs, the works are sub-standard and water is now leaking into the bathroom below.
• A well intentioned owner has arranged for an paid for repairs to common property and now seeks reimbursement. He or she states that "this is the way it was always done in the past".
• A well intentioned owner has replaced a window to their apartment (at their cost) and now other owners are complaining.
• etc

The complexity with repairs is that the repaired item remains common property, so the responsibility to do the repairs again (properly) is the owners corporation.