In the Wye Valley, Rosa and Craig battle the never-ending elements to convert a family-owned, century-old, decommissioned steam railway reservoir into a unique living space.

Devoted dad Danny builds a sustainable but affordable house with bedroom pods on stilts up among the trees. But with no self-build experience and spiralling costs, can he do it on ambition alone?

In 2013, Jon Martin and Noreen Jaafar started building a giant treehouse in Gloucestershire. By 2016, the money ran out. Are they finally living up in the trees? (Revisited from Season 17 Episode 1)

Graeme and Melanie want to squeeze a bright red-clad modernist house onto a tiny twin garage plot with no surrounding land. It'll be cleverly laid out to maximise space over three floors, including bedrooms for their daughters in a new basement.

Furniture maker Lucinda wants to construct a beautifully crafted, two-storey, highly insulated timber home in the woodland of South Herefordshire on a very modest budget, and without using heavy machinery.

Duncan and Liz build a revolutionary Passivhaus Premium powerhouse of a home in the Cotswolds. But with a spiralling schedule and lonesome living, will it really all be worth it in the end?

Leigh and Richard planned to transform a derelict 17th-century flour mill, full of rotten timbers and riddled with structural cracks, into a warm, contemporary, four-floor, three-bed home. (Revisited from Series 21: Episode 5 in 2021)

In 2019, Olaf and Fritha set out to build on a tricky slice of land in West Sussex, boxed in by an A-road and a train line. Kevin McCloud returns to see how their triangular triumph is faring.