Construction Insurance (for an owner-builder this is usually referred to as owner-builder insurance):

For the most part you need the same insurance as is held by registered builders. Construction insurance is available in two common forms; "Annual" and "Single Project". While a registered builder would normally take out the Annual version, an owner-builder would obtain the Single Project type. Otherwise the cover is the same.

Construction Insurance is split into two categories; Contract Works which covers material loss and/or damage, and Public Liability (the biggest risk) which covers your legal responsibilities as a builder. The legal exposure includes scenarios involving damage to others' property and also injuries to third parties.

Workers Compensation:

One of the core responsibilities of an owner-builder is to maintain site safety. Contractors can and do make Workers Compensation claims against both Registered Builders and Owner-Builders. The only possible way to avoid this risk is to ONLY engage incorporated contractors (ie those with "Pty Ltd" on their business names) AND also to ensure without any doubt that they hold current Workers Compensation policies themselves.

This is practically impossible because a) As an owner-builder you will want to use the best contractor for each job, and who is available to do the work when you want it done, b) It's very easy to make a mistake. For example a sole trader may say "don't worry, I have my own workers comp insurance". He may even prove it to you. As his company is not Pty Ltd this does not aid your cause, because he legally cannot cover himself under his own insurance (the system provides that he claim against you), c) Workers Compensation legislation includes an "anti-avoidance" condition, so any policy of restricting who you hire in the way described above can be seen as a violation of that condition. Which brings us back around the loop to the beginning; you need Workers Compensation insurance.

Voluntary Workers:

This is optional. Effectively it is a group income protection cover, designed for owner-builders who are intending to be physically involved in labouring on the project. As it is a group cover, it also extends to friends and family who voluntarily, and without being paid, assist you in the work. If you are intending to be actively involved in the project this type of cover is invaluable. If you only intend to manage the project, you may not require this type of cover.