Overview: This week, Lisa and Michael attempt to convert a 400-year-old barn into an eco-friendly family home. The project begins well, but progress is slow thanks to problems with planning permission, bad weather, illness and damp. Will the couple manage to complete the build before another winter arrives? For many years, entrepreneurs Michael and Lisa have dreamed of creating a sustainable life for themselves and their two children, four-year-old Thomas and three-year-old Lucy. To turn their dream into reality, they plan to convert a 400-year-old barn in rural Nottinghamshire into a contemporary, eco-friendly family home with six bedrooms and five bathrooms. The couple also want to reinstate a 1960s extension to house a wet room and a snug. The new house will feature all the latest environmental technology, including doublethick insulation, a rainwater-harvesting tank and a heat-recovery system. Michael and Lisa bought the barn and six acres of land for £495,000 and plan to spend £450,000 on the renovation. After living on site in a caravan for a year, the couple finally receive planning permission for the conversion and can start work. However, the builders’ quote comes in at £560,000 – a massive £110,000 more than the couple were expecting. To cut costs, Michael decides to take on much of the work himself. He begins by excavating the original sandstone to rebuild the extension and digging trenches for the ground-source heat pumps. Despite beginning well, the project soon runs into trouble. When the coldest winter for 30 years arrives, it looks as if the roof could fall in and take the walls of the barn with it. The cold weather delays the work as the lime mortar used to repair the walls cannot set in freezing temperatures. In addition to the weather, the family must also cope with Lisa’s illness. As a lupus sufferer, she is often unable to work, meaning Michael must manage the build alone whilst looking after the children and running the rainwater-harvesting business. To top it all, problems with the bank then threaten to derail the whole project. As the delays begin to mount, Lisa worries that they will have to spend another winter in the caravan. To spend more time on site, Lisa brings home work from the office, while Michael plants 4,000 trees that will be turned into fuel for the new house. However, as one problem is solved, another arises. This time, it is damp in the extension causing concern - while Michael’s exacting standards lead to their own delays. It is not until the 100-tonne steel frame finally arrives that the build begins to take shape. For the first time, Lisa and Michael can see that the barn is slowly turning into their dream home. Can the couple finish the build on time, or are Thomas and Lucy set to spend another cold winter in the caravan?