Kevin McCloud follows more ambitious self-building projects, beginning with Bryony and Matt, who have spent five years planning the perfect Cornish family beach house, complete with its own surfboard room. But with the project up and running, they have only given themselves a year to finish, despite aiming for passive house standards and with construction of the irregular frame to be done almost entirely on site and by hand - not to mention their busy home and work lives.

Kevin McCloud follows architect Peter and his TV producer wife Emily as they take on the challenge of building twin conjoined houses in London - the plan being to sell one of them to fund the one they will eventually live in. They already have business partners - and potential new neighbours - who have bought into the scheme. Now all they need to do is build the houses. But from the start they are dogged by financial issues - not to mention problems with the experimental nature of the design. Can the two couples retain their friendship?

Seb's designing, project managing and building an ambitious house all by himself, with a cladding system that he's devised himself, in his grandparents' back garden. No pressure then!

Jana and Rory's conversion of an old driving test centre into sleek upside-down living has stalled over the years. With drive and determination, can they finally take the project up a gear?

Kevin revisits Chris and Gill's ambitious Huddersfield mill conversion. Has their meticulous, perfectionist approach stood the test of time? And does their home still feel as radical today?

Kevin McCloud returns to energy conservationist Andrew's pioneering but complex self-heating home, powered by insulated earth banks. Has this ambitious thermal experiment broken new ground?