Greater Sydney and many historic towns across NSW contain a wealth of fine historic houses and residential flat buildings. Many of these houses are individually heritage listed and/or located in Heritage Conservation Areas, generating an extra level of heritage planning controls to protect the significance of the place, and its contribution to the streetscape and surrounding neighbourhood. Historic research into the multi-layered evolution of each building and the identification of its various aspects of heritage significance, are crucial to the success of the design direction and subsequent development approval. The blending of new accommodation with the architectural character of the house and it s presentation to the streetscape of the Heritage Conservation Area, is often a challenging task, requiring close cooperation between the architect and heritage consultant.