CGT is always are complex area,In relation to Capital Gains Tax (CGT) Improvement Thresholds, Certain improvements to pre-CGT assets will be deemed to be separate post-CGT assets where the cost base of the improvement (and 'related improvements') exceeds both the improvement threshold for the income year in which a CGT event happens in relation to the original asset (e.g., the sale of the asset) and 5% of the capital proceeds from the event. I hope this assists.