Owatrol white decking paint has a coverage rate of approximately 8 to 10 square metres per litre per coat. To calculate how much you need, measure the total area of your decking in square metres and divide by 8 to 9 for a conservative estimate across two coats. It is recommended to purchase enough product to complete the entire job in one go, and to mix all tins together before you begin — this avoids any minor colour variation between batches, which is particularly important with a bright colour like white.