The three-dimensional modelling of buildings using set-backs, projecting bays or gables should play a deliberate role in the street scene. Such modelling can have significant effects on shadowing and the play of light. An overhanging first floor or jetty is a useful device which visually separates each floor of a house, allowing greater flexibility in the positioning of windows. Houses or parts of houses that rise to three storeys are useful ingredients in the townscape. They can enclose space, terminate a view or add variety.

Present-day living requirements have created a tendency to group single-storey elements outside the main, two-storey volume of the house – usually around the entrance. Such elements include enclosed porches, bin stores, cloakrooms and meter cupboards. 

While enclosed porches can provide a buffer against traffic noise and weather (as well as reducing heat loss), traditionally such additions were added to the rear of the house. Current practice compromises the clarity of the dwelling and its relationship to the street. Where necessary, these elements should fall within the main, two-storey volume of the house or to the rear of it. Though of course, this is not as crucial in low-density situations where the house does not relate so closely to the street.