It's the height of summer and Kevin McCloud's simple shed has already been transformed with the addition of a cliff top terrace and a sun room made from old lorry and airplane windows. Now Kevin plans to take his off-grid beach build to an entirely new level with a magnificent observation tower, three times higher than a double decker bus. Kevin also wants to enhance his cooking facilities and make an amazing barbecue by re-purposing a World War Two naval mine. Spectacularly, Kevin opts to form the barbecue by blasting the mine in half with a huge explosive charge.