Psychologist Paul North has employed his son Josh to take on the unique task of building a bullet proof earth berm house, deep in Victoria's Yass Valley, to protect them from bushfires and the extremes of climate change.

Rita and James have just 230 thousand dollars to self-build a sustainable, off-grid family home for themselves and their two kids. They plan to use recycled plastic bags, milk cartons, home-made bricks, and an earthen floor.