Interior Space

Space is a prime ingredient in the designer's palette and the quintessential element in interior design. Through the volume of space we not only move; we see forms, hear sounds, feel gentle breezes and the warmth of the sun, and smell the fragrances of flowers in bloom. Space inherits the sensual and aesthetic characteristics of the elements in its field.

Space is not a material substance like stone and wood. It is inherently formless and diffuse. Universal space has no defining borders. Once an element is placed in its field, however, a visual relationship is established. As other elements are introduced into the field, multiple relationships are established between the space and the elements, as well as among the elements themselves. Space is formed by our perception of these relationships.

The geometric elements-point, line, plane, and volume-can be arranged to articulate and define space. In architecture, these fundamental elements become linear columns and beams, planar walls, floors, and roofs.

• A column marks a point in space and makes it visible in three dimensions.
• Two columns define a spatial membrane through which we can pass.
• When supporting a beam, the columns delineate the edges of a transparent plane.
• A wall, an opaque plane, marks off a portion of amorphous space and separates here from there.
• A floor defines a field of space with territorial boundaries.
• A roof provides shelter for the volume of space beneath it.

In architectural design, these elements are organized to give a building form, differentiate between inside and outside, and define the boundaries of interior space.

A building's form, scale, and spatial organization are the designer's response to a number of conditions-functional planning requirements, technical aspects of structure and construction, economic realities, and expressive qualities of image and style. In addition, the architecture of a building should address the physical context of its site and the exterior space.

A building can be related to its site in several ways. It can merge with its setting or dominate it. It can surround and capture a portion of exterior space. One of its faces can be made to address a feature of its site or define an edge of exterior space. In each case, due consideration should be given to the potential relationship between interior and exterior space, as defined by the nature of a building's exterior walls.

Buildings affect and are affected by conditions of their sites and the wider environment. Selecting and developing sites to reduce site disturbance, stormwater runoff, heat island effects, and light pollution contribute to sustainable design.

A building's exterior walls constitute the interface between our interior and exterior environments. In defining both interior and exterior space, they determine the character of each. They may be thick and heavy, expressing a clear distinction between a controlled interior environment and the exterior space from which it is isolated. They may be thin, or even transparent, and attempt to merge inside and outside.

Windows and doorways, the openings that penetrate a building's exterior walls, are the spatial transitions between exterior and interior space. Their scale, character, and composition often tell us something about the nature of the interior spaces that lie between them.

Special transitional spaces, belonging to both the outside world and the inside, can be used to mediate between the two environments. Familiar examples include a porch, a veranda, or an arcaded gallery.

Many single-family residences have steps at all entrances that present barriers to people with physical disabilities. Visitability is a movement to construct new homes so that they can be readily lived in and visited by people with mobility impairments.

Entrances mark the transition from here to there.

Upon entering a building, we sense shelter and enclosure. This perception is due to the bounding floor, wall, and ceiling planes of interior space. These are the architectural elements that define the physical limits of rooms. They enclose space, articulate its boundaries, and separate it from adjoining interior spaces and the outside.

Floors, walls, and ceilings do more than mark off a simple quantity of space. Their form, configuration, and pattern of window and door openings also imbue the defined space with certain spatial or architectural qualities. We use terms such as grand hall, loft space, sun room, and alcove not simply to describe how large or small a space is, but also to characterize its scale and proportion, its quality of light, the nature of its enclosing surfaces, and the way it relates to adjacent spaces.

Interior design necessarily goes beyond the architectural definition of space. In planning the layout, furnishing, and enrichment of a space, the interior designer should be acutely aware of its architectural character as well as its potential for modification and enhancement. The design of interior spaces requires, therefore, an understanding of how they are formed by the building systems of structure and enclosure. With this understanding, the interior designer can effectively elect to work with, continue, or even offer a counterpoint to the essential qualities of an architectural space.

Buildings typically consist of physical systems of structure, enclosure, and building services equipment.

Structural Systems

• The superstructure is the vertical extension of the foundation system and consists of the columns, beams, and load-bearing walls that support the floor and roof structures.
• The foundation system is the substructure that forms the base of a building, anchors it firmly to the ground, and supports the building elements and spaces above.

These systems must work together to support the following types of loads:

Dead Loads: How a building is constructed determines its dead load, which is a static vertical load comprising the weight of its structural and nonstructural components, including any equipment permanently attached to the structure.

Live Loads: How a building is used determines its live load, which is a movable or moving load comprising the weight of its occupants and any mobile equipment and furnishings. In cold or wet climates, collected snow and water impose an additional live load on a building.

Dynamic Loads: Where a building is located determines its potential to bear a dynamic load, which can change suddenly due to the forces of wind and earthquakes.

Enclosure System

• The building envelope consists of exterior walls, windows, doors, and roof, which protect and shelter interior spaces from the exterior environment.
• Interior walls, partitions, and ceilings subdivide and define interior space. Many of these components are nonstructural in nature and carry no loads other than their own weight.

Building Services

• Mechanical systems provide essential services to a building, such as the heating, ventilation, and air-conditioning of interior spaces.
• Plumbing systems supply water suitable for human consumption and firefighting, and dispose of sanitary waste.
• Electrical systems control and safely distribute power for lighting, equipment, security, communication, and vertical transportation.

A building's structural system is formed according to the geometry of its materials and the way they react to the forces applied to them. This structural form and geometry, in turn, influence the dimensions, proportion, and arrangement of the interior spaces within the building volume.

The two basic linear structural elements are the column and the beam. A column is a vertical support that transmits compressive forces downward along its shaft. The thicker a column is in relation to its height, the greater its load-bearing capacity and its ability to resist buckling resulting from off-center loading or lateral forces.

A beam is a horizontal member that transmits forces perpendicular to itself along its length to its supports. A beam is subject to bending and deflection, which result in an internal combination of compressive and tensile stresses. These stresses are proportionally greater along the upper and lower region of a beam's cross section. Increasing depth and placing material where stresses are greatest optimize a beam's performance.

Beams are subject to bending.

Increasing a beam's depth enables it to span greater distances.

Columns mark points in space and provide a measure for its horizontal divisions. Beams make structural and visual connections across space between their supports. Together, columns and beams form a skeletal framework around interconnected volumes of space.

A linear structural system may suggest a grid layout of repetitive spaces, but floor, wall, and ceiling planes are necessary for the support and enclosure of interior space. Floor and ceiling planes, which define the vertical limits of space, may consist of planar slabs or a hierarchical arrangement of girders (large primary beams) and beams and joists (a series of smaller, parallel beams). Walls and partitions need not be load-bearing and do not have to be aligned with the columns...