Few people would be brave or foolish enough to buy a building plot for their family home without visiting it first. But that’s exactly what ex-RAF pilot Jon and GP Gill did. This intrepid pair want to build a New Zealand style hill house on the slopes of the Malvern hills. But when no builders want to take on this ambitious architecture project, the couple decide to make a very risky decision.

Neurologists Penny and Mark have differing views on architecture. Penny has a passion for cutting edge contemporary while Mark loves period buildings. They want to build a family home that satisfies both their tastes. Buying a derelict Victorian gatehouse on a very steep hill in north London, they plan to merge their visions. But will it work, or lead to a compromise that satisfies no-one?

There’s no doubt that the Brits love their sheds. But not many of them would want to actually live in one. Not so young architect and shed fanatic Micah in County Down. He wants to re-invent a dilapidated old agricultural building as an innovative upside down four-bedroom shed using techniques never before seen in Northern Ireland. But a dwindling budget and a new baby soon pile on the pressure.

Golf-coach Chris and ex-figure skater Kayo want to build a home next to one of Britain’s most historic abbeys in Hertfordshire. But constrained by urban planning conditions, they’re relying on an innovative design from architect Rogan. But his vision so unique, and detail orientated, their faith in Rogan is soon tested to the limit. Will they even like their radical home when it’s finished?

Beth Dadswell and Andrew Wilbourne love architecture and ‘shabby chic’. As designers, they are passionate about preserving the marks of time. They’ve purchased a crumbling old Victorian dairy in South London and plan to convert it into a family home. They want to keep as much of the decay as they can. But will their love of rust and ruin lead to their dreams remaining unfulfilled?

Taking inspiration from an ammonite shell, engineer Stephen Tetlow and horticulturalist wife Elizabeth attempt one of the most ambitious homes ever seen on Grand Designs. They want to build a scaly, curving house reminiscent of a giant coiled snake land in the beautiful Blackdown Hills of Devon. It’s a huge, grueling labor of love. But will all the effort be worth it?

Ecologist Fred and communications manager Saffron live in a beautiful village in the Peak District. After 15 years of saving and planning, they’re finally able to start building their large new family home on a steep slope. But the difficulty of excavating into solid limestone soon stalls the project. And when the money runs out, the couple might be left with only a giant hole in the ground.

To sidestep London’s eye-watering real estate costs, designers Joe and Lina plan to build their own house for just $200K. On a miniscule 38 square meter plot, in a run-down part of East London, Joe has designed a split level, six half floor house that will cleverly maximize space. But will adding more design flourishes to this tiny gem of a building become a budget-busting obsession?

In 2007, Ed and Rowena started to build a handcrafted house in Herefordshire on a tiny $100k budget. Using his carpentry skills, Ed decided to do most of the work himself, which meant progress was glacially slow. Four years in, the house was still a shell, with no internal walls. Now, five years beyond that, what state is the house in? Was the project abandoned or did Ed create his masterpiece?