A young couple purchased a grand Georgian cottage which had neighbouring houses purported to be designed by Lutyens. The roof was leaking and there were bats located in the attic as well as open attic voids between neighbours. As a first phase the roof required emergency repairs and stabilising works before the main house could be repaired and brought up to modern standards of comfort. The roof works were controlled under Natural England strict controls around bat preservation. Likewise a new fire break between the properties was carefully designed allowing free passage of the resident bat population. Party Wall agreements were required with both neighbours. This meant eccentric foundations for the new extension. The main refurbishment phase included entirely new facilities (several bathrooms and a two-part kitchen). A large unashamedly modern glass extension was added to the rear elevation connected by new arched brick openings to the older parts of the house. Light levels were enhanced by unblocking the stair window providing continuous views from front to back. New utilities and soakaways were carefully integrated under existing paths and a rear patio. For the thermal upgrade breathable wood-fibre insulation was applied to the interior face of the external walls. Repointing, repairs and stabilisation were required to walls floors and ceilings. Ventilation measures were carefully disguised by clay air-bricks that matched those as found, and discrete vents were fitted to the soffits of the eaves. The challenges faced in working with period buildings were addressed in a systematic way including using existing voids, introducing new breathable insulation, providing passive as well as continuous background mechanical ventilation and avoiding penetrating services into the attic void by air admittance valves.