definition
strict definition
perimeter form
The outline shape of a horizontal cross section at the majority of a building's floor levels.
The perimeter form describes the dominant outline of a building when seen from above, or in a floor plan. When the building's shape changes from one floor to another, the perimeter form which best describes the prevailing outline is chosen.
The outline is considered across the building's floor levels. A small change at one floor need not be the prevailing shape of the building as a whole.
Roof form describes the upper shape, while perimeter form describes the plan outline. Similar roofs can cover buildings with different plan shapes.
More specific definitions
21 sub-definitions-
arc
A building plan following a single open curve without reversing direction or closing into a loop. -
circle
A roughly circular building outline, including regular polygons with nine or more sides and minor perimeter details. -
cross
A building plan formed by two straight members intersecting within 22.5 degrees of a right angle. -
ellipse
An oval or nearly oval building plan, including a rectangle with two curved sides blending into a continuous outline. -
heptagon
A building plan with seven discernible principal sides meeting at convex angles, with unequal sides permitted. -
hexagon
A building plan with six roughly equal principal sides meeting at similar convex angles. -
irregular
A building plan whose overall outline cannot readily be assigned to another defined perimeter form. -
jagged polygon
A building plan with many corners and several perimeter indentations, arranged regularly or irregularly. -
multi-winged
A building plan with at least two wings branching from a spine, excluding wings that all radiate from one point. -
octagon
A building plan with eight roughly equal sides, including sufficiently chamfered squares that appear octagonal. -
open angle
A building plan with two roughly linear segments meeting at one point, or a simple shape with a notch of at least 45 degrees. -
parallelogram
A floor plan with 4 sides in 2 parallel pairs which do not meet in right angles. -
pentagon
A building plan with five principal sides, allowing unequal lengths and minor notches or corner changes. -
radial-lobed
A floor plan in the shape of a flower or star, with radial wings arranged around a common center. -
rectangle
A floor plan with 4 sides meeting at right angles and one axis longer than the other. -
semicircle
A building plan with one main straight edge and one arc, occupying no more than 75% of the corresponding circle or oval. -
square
A four-sided building plan with right-angle corners and side lengths differing by no more than 5% of the shortest side. -
trapezoid
A four-sided building plan with nonparallel sides, distinguished here from square and rectangular plans. -
triangle
A building plan with three dominant straight sides, allowing unequal lengths and slightly rounded or chamfered corners. -
wave
A building plan following one curved path with at least two rounded bends in alternating directions. -
zig-zag
A floor plan with 3 or more sections connected in a line bending in alternating directions.
Related definitions
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architectural style
A classification of a structure's appearance in terms of design vocabulary and historical period. -
elevator type
The mechanical classification of vertical transport systems by the type of lift mechanism. -
entrance approach
The basic form in which a pedestrian main entrance of a building is reached from outside. -
facade color
Colors covering at least ten percent of a structure's facade, excluding windows and allowing distinct or combined patterns. -
facade material
The primary material(s) of a structure's exterior surface, except for windows. -
facade system
The arrangement of exterior cladding over at least ten percent of the facade, excluding thin surface coatings such as paint. -
feature
Special properties or facilities directly associated with a built object, including amenities and physical characteristics. -
flooring material
The substance and form applied to the floors throughout a structure or a module. -
foundation system
The type of structure which gives structural support to a building beneath its lowest floor or ground base. -
frame material
Materials forming a structure's load-bearing skeleton, distinct from finishes, removable partitions, and foundations. -
framing system
The principal structural framework resisting gravity and lateral loads above ground, distinct from the foundation system. -
heating type
The energy source and, where applicable, delivery system used to heat a building's main occupied areas. -
insulation material
Forms and substances used as thermal insulators in building walls, roofs, and facades. -
insulation position
The position of thermal insulation materials with respect to the structural perimeter walls or framework of a building. -
level
The position and form of an entity acting as a company within a corporate organization or partnership. -
lighting system
The basic format of electrical structure or appliance used to illuminate the interior of a building. -
qualitative indicators
Predefined or subjective measurements of various qualitative aspects of properties. -
roof covering
The substance and layout of the material used to cover the upper surface of a building. -
roof form
The prevailing shape of a building's roof or top section, using the most prominent form where several occur. -
roof frame material
The material forming the structural framework that supports the outer covering of a building's roof. -
secondary facade material
Material used for the non-display side(s) of a structure, or used in less than 10% of its facade area. -
staircase material
The framing material which supports the steps and risers in an object's stairways. -
stairway configuration
The general path of a stairway, describing the directions of individual flights and the connections between flights. -
storage type
The basic arrangement of facilities for storing large quantities of items, commodities, or materials. -
tenancy design
The intended arrangement of a building's space for one or more tenants, including private and shared occupancy provisions. -
window frame material
The material forming the frames that hold a structure's windows in place or allow them to move. -
window type
The type used for a majority of a building's windows, indicating whether and how they open, and how they are divided.