This episode is all about adding one extra room. One extra room would make all the difference to Drew and Carrie Brooke-Mellor in Hastings, but to get it they need planning permission to convert their cellar into a habitable space. And one extra room would help Richard Snape who has teenage children. He wants to increase the size of his ground floor by a whopping 25 per cent.Can Drew and Carrie persuade the planners to give them the green light? How much does it cost to add one extra room? And will Richard build his huge extension in time for his fiftieth birthday?