Grand Designs

Rob Hodgson and Kay Ralph plan to build a sleek glass-fronted house on a crumbling clifftop in Gwynedd, taking inspiration from the villas of California. However, access will be extremely difficult and expensive because of a low bridge over the narrow track to the site, and problems arise when one of the heaviest storms in recent history batters the coast. To make matters worse, erosion specialists predict the property could fall into the sea within just 60 years and the pair are prohibited from reinforcing the cliff face.

Product designer Rebecca Sturrock has returned to her family home in Cornwall with her partner Gregory Kewish and a highly ambitious plan. Together they hope to transform a small, damp bungalow into a cutting-edge home to share with their twin three-year-old daughters - all for just £80,000. The design is radical - to reinforce the walls of the old property and add a new living space on top to take advantage of the views. This extra floor will be made entirely of thick wooden panels engineered in Germany and normally assembled by a crew of specialist installers. However, budget constraints mean the couple are determined to do it all themselves.

GP Peter Berkin and his wife Chard, an alternative medicine practitioner, have decided to build a new home at the bottom of their garden, but cannot agree on any part of the design - even the basic shape. Peter is a keen hobbyist who wants the house to feature a workshop where he can build a plane, and he's planning to spend twice the £200,000 budget Chard has in mind. Kevin McCloud follows their progress.

Architect Patrick Bradley has come up with an unusual £100,000 house design built out of four 45ft shipping containers, welded together to form a giant cross and cantilevered over the top of a stream on the family farm in County Londonderry. His mother is hoping the new home will help her son find a girlfriend, but the small budget and tight schedule soon pose problems

Tracy Fox and husband Steve want to build an "urban shed" featuring two studios, three bedrooms and a double-height space with a walkway, made out of industrial-style materials including corrugated cement fibreboard and 20ft panels of polycarbonate sheeting. Having discovered an old milk yard tucked away behind some flats and shops in south-east London, their long-held desire to build a highly unconventional family home and workspace begins. But their choice of unorthodox materials proves challenging and costly.

Natasha Cargill wants to build a home shaped like two enormous periscopes in rural Norfolk, but to obtain planning permission, she has to ensure not only that the materials are sustainable, but also agree to measure the transportation used to deliver them. If these strict criteria are not met, she won't be allowed to live there, and to add to the pressure, she has just £330,000 to spend on construction and six months to complete the project

Kevin McCloud follows software executive Andy Bruce and garden designer Nicki Bruce, who are planning to build a "floating" house on the River Thames, which would be the first of its kind in the UK. Their architect has come up with an ambitious, experimental design that would see the whole property magically rise up with the flood waters. However, no one knows whether it will work, and the project soon becomes bogged down in the logistical challenges of bringing to fruition such a complex structure on a small island that is only accessible by a narrow footbridge.

Kevin McCloud revisits a memorable restoration project in the remote Creuse region of central France. Back in 2003, when Denise Daniel and Doug Ibbs gave up everything in the UK to start a new life abroad, they couldn't have known what was ahead of them. Falling in love with a dilapidated manor house with just four crumbling walls and half a roof, they embarked on a mission to transform it - working day and night, doing everything themselves, year after year - until slowly but surely they created a magnificent edifice out of the ruins they bought off the internet. It's now the 70th anniversary of the destruction of the original 19th-century building by the German army - and the house is finally finished.

Kevin McCloud revisits a unique Japanese-Welsh fusion home in the Wye Valley, completely transformed from a damp old forester's house in 2013. Tamayo Hussey has missed Japan ever since she moved to the UK 15 years ago with her husband Nigel. To stave off the homesickness they decided to turn the property into a one-of-a-kind home, complete with roof bath, tatami room and sliding paper walls. Kevin finds out how this somewhat improvised building weathered one of the wettest winters on record and if it has brought the calm and tranquillity Tamayo remembers from her childhood in the Far East.

Kevin McCloud returns to Devon for an update on an inspirational build. Royal Marine Captain Jon White and his wife Becky were living happily in a small cottage when in June 2010, while serving in Afghanistan, Jon stepped on an improvised explosive device, losing three limbs. Every part of their lives had to change - starting with where they could live. Their architect came up with a cutting-edge, semi open-plan building with a dramatic wing-like-roof - and crucially no obvious signs of adaptations for Jon's disabilities. Has the new home proved as enabling for the couple and their expanding family as they had hoped?