Grand Designs - Season 26

Kevin McCloud follows more of Britain's most ambitious self-building projects, as intrepid individuals attempt to design and construct the home of their dreams. Howard and Sarah embark on their most ambitious building project yet - a sleek, angled, metallic floating home on a tidal estuary near Worthing. Designed to look like a boat, and nestled within an idiosyncratic houseboat community, the structure will sit on an experimental prefabricated polystyrene slab to deal with high tides alternating with hours sitting in the mud. It's a huge experiment, with £385,000 to spend over an 18-month schedule, especially as they'll be doing much of the work themselves and finalising the engineering as they go. Things get off to an agonisingly slow start when it takes months to painstakingly remove a condemned D-Day landing craft from the plot before they can even get started and the constant tidal shifts that disrupt any construction creates a real recipe for disaster.

HR director Sarah and technology director Pip are determined to transform a 150-year old rickety barn that's in danger of keeling over, into a modern five-bedroom home with space for their expanding pet family. Given their ambitious budget of £420,000, they try to keep as much of the original structure as possible to save on costs, but the fragile building starts to unravel almost as soon as work begins. Under pressure on all fronts, and not always seeing eye-to-eye on what the end result should be, Sarah and Pip draw on every ounce of resolve to make it through.

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. Pulling off this daring feat proves difficult, when far deeper than anticipated foundations have to be removed, horrendously wet weather causes problems and unexpected costs arise.