Plan
Floor plans are the most common type of this architectural drawing, showing the home's intended features and the path of movement
A plan is one of the three principal types of architectural drawings, in which a three-dimensional design is described in two dimensions. The others are elevation and section. In each case the observer's line of sight is perpendicular to the plane upon which the building's elements and surfaces are projected. In the case of a plan, it is a level plane — parallel to the floor or ground — that hypothetically cuts through a building at about waist height (approximately 3 feet, 6 inches above the floor) so as to include windows.
Architects like Frank Lloyd Wright (his Rosenbaum House plan is seen here) use the floor plan to develop an underlying logic that drives space, construction, scale and texture. The rectangular grid is both the joints of the concrete floor and the means of locating walls, doors and windows.
Floor plans are extremely important tools that help architects work out alternative schemes. What happens if the stair moves? Or if the kitchen is a galley instead of an L shape? With CAD (computer-aided drafting), it's easier than ever to work out a myriad of alternatives.
An architect's working drawings (the set used for pricing, bidding and construction) can be confusing. On top of the plan's walls, doors and windows are dimensions, references to other drawings, many notes and tags for types of doors, walls and other assemblies.
Site plans follow the same orthographic rules as floor plans, but they are typically elevated above the building (a variation can include a floor plan within a landscape plan, allowing one to see how the exterior and interior spaces relate). Site plans like this one focus on tree and plant size and placement, topography (through contour lines) and site elements such as walls, walks and driveways.
See What You Can Learn From a Floor Plan