In this final episode, Kevin exclusively reveals the winner of the most prestigious prize for residential architecture, the Riba House of the Year 2018. But first, alongside architect Damion Burrows and design expert Michelle Ogundehin, he explores the last group of houses on the long list. Each one uses materials in interesting ways. In leafy Berkshire, there's a perfectly crafted timber box, with sleek concrete floors and giant six-metre windows. In Belfast, there is a small but perfectly formed house with black larch cladding. In Surrey, a completely revamped 1930s house with a pale brick and glass modernist extension blends beautifully into its setting. And finally, an experimental house in London makes the materials it's built from part of the design. Kevin then reveals which of these properties has made it onto the shortlist before exclusively announcing the overall winner of House of the Year.

Kevin McCloud, architect Damion Burrows, and design expert Michelle Ogundehin visit four more stunning homes looking to be crowned Riba House of the Year 2018. This time, the theme is Extreme Houses. There's an awe-inspiring set of cantilevered black boxes which push the limits of engineering; a far-flung 21st century crofter's cottage by a Loch in Scotland; a curvaceous minimal concrete home in London; and in Northern Ireland, a sculptural home designed around a single shape - the wedge. Which of them will make it onto the shortlist for the overall big prize?

Five inspiring homes with a past bid for a place in the final, including a London gin distillery, a Devon farmhouse and a 400-year-old wreck

A beautiful red house and a controversial glass building in Henley are just two of the daring, spectacular homes competing to go through to the final of the prestigious architectural award