Howard and Sarah build a radical metallic floating home designed to look like a boat, nestled within an idiosyncratic houseboat community on a tidal estuary near Worthing. But will it sink or swim?

Sarah and Pip are smitten with a 150-year-old Bedfordshire barn that's keeling over. Can they retain its charm and spirit, while at the same time transform it into a sleek, modern home?

Recently widowed 82-year-old Kathryn plans to build a new, accessible, ultra-sustainable home right next door to the home she lived in with her husband Jon, where a garage and extension currently sit. It'll be a mirror image of her current Edwardian house, but with a 21st-century twist.

Kevin revisits Graeme and Melanie, whose hugely ambitious Hackney haven was hampered by a basement bombshell. Have they finally got out of the red and into their modernist home?

Does good architecture have the power to heal? Kevin revisits Elinor and Born, who built a clean-aired, hypoallergenic house, motivated by their two boys' extreme allergies.