When 17-year-old Ruben told his parents, Helen and Tim, that he wanted to build a mud hut in their Oxfordshire garden as his A-level project, they had no idea how much work they would all have to put into it. Now they have run out of steam and have called in Simon and his team to help them carry on the project and turn Ruben's traditional cob hut into a source of income to finance his gap year travels.Simon starts by ordering the demolition of dad Tim's attempt at a mezzanine and takes him and Ruben to the traditionally built Courtfield Thatched Roundhouse in Milton in Somerset. It's made from wattle and daub and built by Amada and thatcher Tom, and the visit fills Ruben with enthusiasm for traditional building techniques, and back in Oxfordshire, Simon teaches the whole family ‘green wood' techniques to build the new, improved mezzanine.Carpenter Ian Tsang gets to grips with some special pieces of wood to create a dry kitchen and saves a log coffee table, whilst designers Verity Coleman and Sophie Dunn set about creating a warm and inviting interior with mum Helen, building some bespoke upcycled pallet furniture and a truly unique sign for the B&B.