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Architectural Drawings:  An architectural drawing or architect’s drawing is a technical drawing of a building (or building project) that falls within the definition of architecture. Architectural drawings are used for a number of purposes: to develop a design idea, a coherent proposal, to communicate ideas and concepts, to convince clients of the merits of a design, to enable a building contractor to construct it, as a record of the completed work, and to make a record of a building that already exists.

Architectural drawings are drawn according to a set of conventions, which include particular views (floor plan, section etc.), sheet sizes, units of measurement and scales, annotation and cross referencing.

Plan:  Plans are drawings that show a horizontal cut through a structure, exposing a building’s organization of rooms and spaces.

  • Floor plan: A floor plan is the most fundamental architectural diagram, a view from above showing the arrangement of spaces in the same way as a map, but showing the arrangement at a particular level of a building. Technically it is a horizontal section cut through a building, showing walls, windows and door openings and other features at that level. The plan view includes anything that could be seen below that level: the floor, stairs (but only up to the plan level), fittings and sometimes furniture. Objects above the plan level (e.g. beams overhead) can be indicated as dotted lines.
  • Site plan: A plan showing the whole context of a building or group of buildings. It shows property boundaries and access to the site, and nearby relevant structures.  A site plan may show adjoining streets to demonstrate how the design fits. The site plan gives an overview of the entire scope of work. It shows buildings (if any) already existing and proposed; roads, parking lots, footpaths, hard landscaping, trees and planting. For a construction project, the site plan needs to show all the services connections: drainage and sewer lines, water supply, electrical and communications cables, exterior lighting etc.

Section:   Sections are drawings showing vertical cuts through a structure. They are used to depict floor and building heights as well as vertical connectivity.

A cross section, also simply called a section, represents a vertical plane cut through the object, in the same way as a floor plan is a horizontal section viewed from the top. Sections are used to describe the relationship between different levels of a building.

A sectional elevation is a combination of a cross section, with elevations of other parts of the building seen beyond the section plane.

Elevation:  Elevations show a wall’s face, expressing where every element is placed vertically on a facade or interior.

An elevation is a view of a building seen from one side, a flat representation of one façade. This is the most common view used to describe the external appearance of a building. Each elevation is labeled in relation to the compass direction it faces. Architects use the word “elevation” as a synonym for façade, so the north elevation is literally the north wall of the building.

Isometric and Axonometric:  Isometric drawings represent the three-dimensionality of a structure or space. Every line’s length in an isometric drawing is represented accurately to scale, but the angles of material connection in an isometric drawing are not correct.

Isometric and axonometric projections are a simple way of representing a three dimensional object, keeping the elements to scale and showing the relationship between several sides of the same object, so that the complexities of a shape can be clearly understood.

There is some confusion about the terms isometric and axonometric. “Axonometric is a word that has been used by architects for hundreds of years. Engineers use the word axonometric as a generic term to include isometric, diametric and trimetric drawings.”

  • An isometric uses a plan grid at 30 degrees from the horizontal in both directions, which distorts the plan shape. Isometric graph paper can be used to construct this kind of drawing. This view is useful to explain construction details (e.g. three dimensional joints in joinery).
  • Cabinet projection is similar, but only one axis is skewed, the others being horizontal and vertical. Originally used in cabinet making, the advantage is that a principal side (e.g. a cabinet front) is displayed without distortion, so only the less important sides are skewed. The lines leading away from the eye are drawn at a reduced scale to lessen the degree of distortion.
  • An axonometric uses a 45 degree plan grid, which keeps the original orthogonal geometry of the plan. The great advantage of this view for architecture is that the draftsman can work directly from a plan, without having to reconstruct it on a skewed grid. In theory the plan should be set at 45 degrees, but this introduces confusing coincidences where opposite corners align.
  • In Planometric or Plan Oblique View unwanted effects can be avoided by rotating the plan while still projecting vertically. This is sometimes called a planometric or plan oblique view, and allows freedom to choose any suitable angle to present the most useful view of an object.

The axonometric gained in popularity in the twentieth century, not just as a convenient diagram but as a formal presentation technique, adopted in particular by the Modern Movement. Axonometric drawings feature prominently in the influential 1970’s drawings of Michael Graves, James Stirling and others, using not only straightforward views but worms-eye view, unusually and exaggerated rotations of the plan, and exploded elements.

Perspective:  Perspectives are drawings that depict what the eye or a camera sees. The drawings are not to scale, but they accurately represent how a structure or space is perceived. Perspective is the view from a particular fixed viewpoint.

Diagrams:  Drawings that express structural data visually. A structural diagram, showing the amount of load or weight a beam must carry, is an example of an architectural diagram.

Reflected Ceiling Plan:  A reflected ceiling plan (RCP) is a drawing, which shows the items that are located on the ceiling of a room or space. It is referred to as a reflected ceiling plan since it is drawn to display a view of the ceiling as if it was reflected onto a mirror on the floor. This way the reflected ceiling plan has the same orientation as the floor plan associated with it. It is as if the ceiling was see-through and you could see right through it to the floor below.

Detail Drawings:  Detail drawings show a small part of the construction at a larger scale, to show how the component parts fit together. They are also used to show small surface details, for example decorative elements. Section drawings at large scale are a standard way of showing building construction details, typically showing complex junctions (such as floor to wall junction, window openings, eaves and roof apex) that cannot be clearly shown on a drawing that includes the full height of the building.


Bay: a division of space that is repeated within a building, a three bay house would have three spaces repeated along one side as in two rooms and a hall.

  • A space that projects from the rest of the building as in a bay window.
  • Architecture:
    • any of a number of similar major vertical divisions of a large interior, wall, etc.: The nave is divided into six bays.
    • a division of a window between a mullion and an adjoining mullion or jamb.
    • bay window
    • an alcove or recess in a wall

Mullion: a vertical structural element which divides adjacent window units. When used to support glazing, they are teamed with horizontal supporting elements called “transoms“.

  • In the commercial door industry, the term is also applied to a piece of hardware that divides the opening of a pair of doors.
  • A mullion acts as a structural member.  It carries the dead load of the weight above the opening and/or the wind load acting on the window unit back to the building structure. The term is also properly applied to very large and deep structural members in many curtain wall systems.

Muntin or Muntin bar:  is sometimes similar in appearance to a mullion, but they are not structural.  A muntin is a strip of wood or metal separating and holding panes of glass in a window.  Muntins divide a single window into a grid system of smaller panes of glass, called “lights” or “lites”.

  • Muntins can be found in doors and windows.
  • Windows with “true divided lights” make use of thin muntins positioned between individual panes of glass.  True divided lights are not typically seen in modern windows as they decrease performance and are more expensive/difficult to implement.
  • In contemporary windows muntins frequently do not actually separate panes of glass, but are decorative elements attached to the inside and/or outside of panes of glass to give the appearance of multiple smaller panes.  This is commonly called a “simulated divided light.”
  • Muntins are frequently mistakenly referred to as mullions.

Jamb:  One of a pair of vertical posts or pieces that together form the sides of a door, window frame, or fireplace, for example.

  • Architecture, Building Trades:
    • either of the vertical sides of a doorway, arch, window, or other opening.
    • either of two stones, timbers, etc., forming the sidepieces for the frame of an opening.
    • A projecting mass or columnar part.

Transom: a bar of wood or stone across the top of a door or window

  • a crosspiece separating a door or the like from a window or fanlight above it.
  • Also called transom light, transom window.
  • a window above such a crosspiece.
  • a crossbar of wood or stone, dividing a window horizontally
  • Compare mullion.  Also called: traverse

Fanlight:  A fanlight is a window, semicircular or semi-elliptical in shape, with glazing bars or tracery sets radiating out like an open fan, It is placed over another window or a doorway and is sometimes hinged to a transom. The bars in the fixed glazed window spread out in the manner a sunburst. It is also called a “sunburst light”.

  • A chiefly British use of the word is to mean “transom“.

Traverse:  a transverse gallery or loft of communication in a church or other large building.

  • Something being or lying across, such as a transom
  • A gallery or loft inside a building that crosses it
  • construction: Crossbeam: something that is set across a gap or lies crosswise, e.g. a structural member of a building
  • buildings :  Gallery: a gallery or loft that crosses from side to side inside a building
  • buildings :  Barrier within building: a railing, curtain, screen, or partition forming a barrier within a building
  • civil engineering:  Survey using intersecting straight lines: a survey made using a series of intersecting straight lines of known length whose angles of intersection are measured for recording on a map or in a table of data

Tracery:  window ornamentation: decorative ribs in windows, especially medieval church windows, and screens

  • interlaced pattern: a decorative pattern of interlaced lines, especially one that resembles the form or patterns found in church windows
  • In architecture, Tracery is the stonework elements that support the glass in a Gothic window. The term probably derives from the ‘tracing floors’ on which the complex patterns of late Gothic windows were laid out

Casement: in a window refers to a vertical window hinged on its vertical side, meant to open either out or in.

  • a window containing frames hinged at the side or at the top or bottom
  • a poetic word for window
  • hinged window: a window that opens on hinges located at one side, as distinct from one that slides up and down

Casing:  Casing is a type of trim moulding used to trim out windows and doors. This trim is called door casing or window casing depending on the application. Casing will come in different sizes and profiles. Two poplar casing are colonial and tear drop.

  • frame for door or window: a frame containing a door, window, or stairway

Clearstory (or Clerestory):  the upper level of a room that extends beyond the single-story height; often found in churches and penetrated by windows.

  • May also refer to the upper row of windows that is close to the ceiling
  • In modern usage, clerestory refers to any high windows above eye level; the purpose is to bring outside light, fresh air, or both into the space.
  • A clerestory is a high wall with a band of narrow windows along the very top. The clerestory wall usually rises above adjoining roofs.
  • Originally, the word clerestory referred to the upper level of a church or cathedral.
  • Pronunciation: Clerestory is pronounced clear story.

Fenestration:  The arrangement of windows across the facade of a building.

  • Fenestration, refers to the design and/or disposition of openings in a building or wall envelope.
  • Fenestration products typically include: windows, doors, louvers, vents, wall panels, skylights, storefronts, curtain walls, and slope glazed systems.
  • the arrangement, proportioning, and design of windows and doors in a building
  • an opening in a surface (as a wall or membrane)

Louver: A louver (American English) or louvre (British English), from the French l’ouvert; (“the open one”) is a window, blind or shutter with horizontal slats that are angled to admit light and air, but to keep out rain, direct sunshine, and noise. The angle of the slats may be adjustable, usually in blinds and windows, or fixed.

Glazing:  Glazing, which derives from the Middle English for ‘glass’, is a part of a wall or window, made of glass. Glazing also describes the work done by a professional “glazier“.

  • Common types of glazing that are used in architectural applications include clear and tinted float glass, tempered glass, and laminated glass as well as a variety of coated glasses, all of which can be glazed singly or as double, or even triple, glazing units. Ordinary clear glass has a slight green tinge but special clear glasses are offered by several manufacturers.
  • Glazing can be mounted into a window sash or door stile, usually made of wood, aluminium or PVC. The glass is fixed into a rabbet (rebate) in the frame in a number of ways including triangular glazing points, putty, etc.. Toughened and laminated glass can be glazed by bolting panes directly to a metal framework by bolts passing through drilled holes.
  • Glazing is commonly used in low temperature solar thermal collectors because it helps retain the collected heat.

So now the big question, is that “window” a window, storefront, or curtainwall?  Generally speaking all three are means to insert glazing, i.e. glass, in the exterior envelope of the building, but there are important technical and cost differences between the three.

Window:  A window is a complete manufactured unit that includes glass, frame, and componentry all in one.  Windows are delivered to the job site ready to install in a framed opening in the building.

  • Windows are most common in residential construction.
  • Big box home improvement stores carry windows, but not storefront or curtainwall.
  • Generally speaking windows are the least expensive of the three systems.

Storefront:  Storefront is different from windows in that it typically does not come to the job site assembled as a complete glazed unit.  The frames are either be pre-assembled and delivered to the site, or can be assembled in a framed opening on site.  The glazing is later installed in the frame on site.  This allows storefront to be more customizable and much larger than a window.

  • In most cases storefront will consist of multiple windows and/or doors in one framed opening in the building envelope.  While multiple windows and doors can be attached to one and other the effect is not as seamless or stable as can be achieved with storefront.
  • Storefront is generally more expensive and durable than windows.
  • Although large windows are available, typically storefront or curtainwall are used when larger individual glazed areas or a large combination of windows and doors is desired.  Ultimately the size of any individual area of glazing is limited by available glass sizes.
  • Storefront is typically used in openings up to two stories in height.  Larger openings require the use of curtainwall to resist wind loads.
  • The name here is telling.  Storefront is typically used at the front of retail stores to allow the store to feel open and welcoming to customers by maximizing visibility.  That being said storefront is also used in many other commercial building applications and even occasionally in custom residential work.

Curtainwall:  Curtainwall is the most complex, durable, and expensive glazing system of the three. That being said it shares one important similarity with windows.  It is typically delivered to a site in fully assemble panels that are ready to hang from the structure.  Where it differs is that the assemblies are large enough to require a crane for installation.

  • Curtainwall also differs from windows and storefront in that instead of being installed in framed openings in the exterior envelope it typically is the building envelope.
  • Curtain Wall Systems are typically designed with extruded aluminum members, although the first curtain walls were made of steel. The aluminum frame is typically infilled with glass, which provides an architecturally pleasing building, as well as benefits such as daylighting
  • Curtain walls differ from store-front systems in that they are designed to span multiple floors, and take into consideration design requirements such as: thermal expansion and contraction; building sway and movement.
  • Although it is accurate to say that curtainwall is non-structural in the sense that it is not part of the structural frame of the building, it is the strongest of the three glazing systems in its resistance to wind loads.
  • Curtain wall is typically suspended from a buildings structural frame.
  • It is typically used on high rise buildings and other large commercial buildings.
  • On smaller projects that do not require the use of curtainwall to resist wind loads it is typically avoided due to its high cost.

Astragal: a symmetrical moulding used in creating panels and horizontal banking in cornice, wainscoting, and pilaster assemblies.

  • a small convex molding cut into the form of a string of beads. Compare bead and reel.
  • a molding attached to one or both meeting stiles of a pair of double doors in order to prevent drafts.
    • An astragal is a moulding profile composed of a half-round surface surrounded by two flat planes (fillets). An astragal is sometimes referred to as a miniature torus. It can be an architectural element used at the top or base of a column, but is also employed as a framing device on furniture and woodwork.

Moulding or molding:  (USA) a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster but may be made from plastic or reformed wood.

  • A “sprung” moulding has beveled edges that allow mounting between two non-parallel planes (such as a wall and a ceiling). Other types of moulding are referred to as “plain”.

Cornice molding: a horizontal decorative molding that crowns any building or furniture element: the cornice over a door or window, for instance, or the cornice around the edge of a pedestal. A simple cornice may be formed just with a crown molding.

Wainscot:  to line the walls of (a room, hallway, etc.) with or as if with woodwork: a room wainscoted in oak.

  • wood, especially oak and usually in the form of paneling, for lining interior walls.  
  • the lining itself, especially as covering the lower portion of a wall.
  • a dado, especially of wood, lining an interior wall.  
  • British. oak of superior quality and cut, imported from the Baltic countries for fine woodwork.

Pilaster:  a shallow rectangular feature projecting from a wall, having a capital and base and usually imitating the form of a column.

  • a shallow rectangular column attached to the face of a wall.

Torus: Architecture. a large convex molding, more or less semicircular in profile, commonly forming the lowest molding of the base of a column, directly above the plinth, sometimes occurring as one of a pair separated by a scotia and fillets and column.

  • Not to be confused with the sign of the horoscope: Taurus the bull.

Scotia: a deep concave moulding, esp one used on the base of an Ionic column between the two torus mouldings.

Fillet: Architecture. A flat narrow molding: a raised or sunken ornamental surface set between larger surfaces. Not to be confused with:

  • Food. boneless portion of fish or meat: a boneless portion cut from a fish, a poultry breast, or the rib area of beef, lamb, or pork.
  • Dress. ribbon worn around the head: a ribbon worn across the forehead, as an ornament or to hold back the hair.
  • Printing. corative line on the cover of book: a thin decorative line impressed onto the cover of a book, or the tool used to make it.