This arrangement requires less site excavation but imposes constraints upon building design at ground level. Ground-floor uses have only a single aspect towards the street and consequently the amount of daylight penetrating the space through the depth of the building is limited. However, the ground floor in this arrangement is very suitable for commercial uses, which can take advantage of the flexible depth the parking area provides to the rear. For retail uses, the space at the back of the shop would be situated under, and ventilated through, the deck above.

Residential and other uses within these building types must take their pedestrian access directly off the street either via individual front doors serving houses or via common entrance lobbies. These should be clearly identifiable to all users. Lobbies must link to the parking area to the rear. All under-deck and underground car parks must incorporate a lift to a ground-level entrance lobby.

Occupiers of buildings will typically find it convenient to have an external staircase from the internal, communal courtyard to the parking area below.

Entrances to underground or under-deck parking areas must:

• be located directly off a street. While entrances should be designed to be as unobtrusive as possible, they should be clearly identifiable to all users. The entrance points should be located so as to avoid the possibility of queuing causing problems within higher category streets. Entrances and access ramps should be no wider than 3.5m with signal-controlled entry and exit for one-way working. Separate pedestrian access needs to be provided to avoid people using the ramps;
• have a maximum gradient of 1-in-7, with a separate entrance for pedestrians. Ideally, ramps should incorporate under-slab heating to avoid ice in cold weather; and
• incorporate electronic entrance gates or shutters to provide a secure environment that can be accessed only by residents and other occupiers of the building.

Underground or under-deck parking areas should also:

• incorporate lifts to ground-level entrance lobbies;
• have a clear floor-to-ceiling height of at least 2.5m;
• be well-lit and finished, ideally with painted floors;
• be naturally ventilated;
• use high-quality materials; and
• consider which colours, patterns and types of surface will best ensure accessibility to users of all ages and a range of physical and mental abilities.