The transmission of certain diseases can occur within a house by the population of insects and animals living within the building fabric. By improving surface finishes of walls, floors and ceilings to eliminate or greatly reduce the presence of cracks and other insect and animal habitat, a considerable reduction in the incidence of a group of diseases is likely. These diseases include plague, typhus, dysentery, hepatitis A and B, relapsing fever, poliomyelitis and Chagas disease. This note describes some common carriers of disease (vectors) to be found in dwellings. It identifies good practice in low-cost house construction to reduce vector habitat.