The manner of connecting one space to another is too often and too quickly resolved by nothing more than a door. Although many of us grow up with nothing more than doors as separators and connectors between rooms if we look more closely at historical examples you’ll see more nuanced ways of linking and separating spaces. This is generally referred to as a threshold – a zone of passage or pause between two spaces, areas or rooms. Thresholds acknowledge that the character of any two adjacent rooms is rarely identical; therefore, some form of transition is often desirable. A door is one of several possible solutions to linking and separating spaces. Screens, passages, unaligned openings, wall thicknesses, among other devices, offer other ways of achieving the same means but with different effects. In some cases, thresholds become so extended that they become intermediary spaces in their own right.
Before throwing in a way, punching a hole and dropping a door in, first ask what the relationship between the two adjacent spaces is. You may find, firstly, that a wall isn’t necessary but that perhaps a screen or row of columns might serve the purpose of separation and individual identity for each space. If a wall is needed, the door isn’t necessarily an automatic solution for passage. A opening in a thick wall might provide enough of a threshold between the two spaces by accentuating the thickness of the wall as a barrier and separator, while remaining connected with a door-less passage. The position of the opening itself, at a corner, in the middle of the wall or room, also provides visual clues as to whether it is normal to pass from one to the other without question.
If a door is used, the location of the hinge side and direction of the swing can either block or provide views inward when the door is left ajar such that an occupant can be more or less inviting by leaving the door partially opened.
Taken further, the idea of thresholds is also about mediating movement from one type of spatial status to another – for example, from a very public to a very private space. A door requires a firm decision to enter, yet you may have no idea of what type of room is on the other side and whether it is permissible or desirable to enter. A threshold space can signal changes in the status so that a greater sense of a private realm is signalled – a thoughtful user will pick up on these signals and understand whether they should proceed. In public buildings such issues are paramount and help to mitigate the necessity for signs, locked doors and sealed off areas. Most public buildings include spaces through which any passer-by may enter and proceed but also include spaces which may be for employees only and hence private. Understanding thresholds as transitions and mediators adds meaning to movement in architecture as well as add clarity to how spaces should be interpreted and used.