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Pair of hip roof dormer windows on the Howard Memorial Hall, Letchworth Paired dormer windows, Letchworth (geograph 4237604).jpg
Pair of hip roof dormer windows on the Howard Memorial Hall, Letchworth
Pier House, by Corry pier, Broadford, Skye formerly Campbell's Temperance Hotel, c. 1880 Pier House, Corry - - 992334.jpg
Pier House, by Corry pier, Broadford, Skye formerly Campbell's Temperance Hotel, c. 1880
A dormer window on the Wijngaardplein [nl
] in Bruges, Belgium 00 Bruges - JPG1a.jpg
A dormer window on the Wijngaardplein  [ nl ] in Bruges, Belgium

A dormer is a roofed structure, often containing a window, that projects vertically beyond the plane of a pitched roof. [1] A dormer window is a form of roof window.

Roof pitch

In building construction, roof pitch is the steepness of a roof quantified as a ratio or as number of angular degrees that one 'exposure' surface deviates from horizontal level. A roof surface may be either 'functionally flat' or pitched.

Roof window

A roof window is an outward opening window that is incorporated as part of the design of a roof. Often confused with a skylight, a roof window differs in a few basic ways. A roof window is often a good option when there is a desire to allow both light and fresh air into the space.


Dormers are commonly used to increase the usable space in a loft and to create window openings in a roof plane. [2] The term "dormer" is commonly used to refer to a "dormer window" although a dormer does not necessarily contain a window. A dormer is often one of the primary elements of a loft conversion. As a prominent element of many buildings, different types of dormer have evolved to complement different styles of architecture. When the structure appears on the spires of churches and cathedrals, it is usually referred to as a lucarne.

Loft near-roof part of a building

A loft can be an upper storey or attic in a building, directly under the roof or just a storage space under the roof usually accessed by a ladder. A loft apartment refers to large adaptable open space, often converted for residential use from some other use, often light industrial. Adding to the confusion, some converted lofts include upper open loft areas. Within certain upper loft areas exist even further lofts, which may contain loft areas of their own, and so forth.

Loft conversion

A loft conversion or an attic conversion is the process of transforming an empty attic space or loft into a functional room, typically used as a bedroom, office space, a gym, or storage space. Loft conversions are one of the most popular forms of home improvement in the United Kingdom as a result of their numerous perceived benefits. The installation of a loft conversion is a complicated process, and whilst it may be possible to attempt a 'DIY' loft conversion, the large amount of work involved often results in many people choosing to contract a specialist loft conversion company to undertake the task.


Some of the different types of dormer are:

Gable Generally triangular portion of a wall between the edges of intersecting roof pitches

A gable is the generally triangular portion of a wall between the edges of intersecting roof pitches. The shape of the gable and how it is detailed depends on the structural system used, which reflects climate, material availability, and aesthetic concerns. A gable wall or gable end more commonly refers to the entire wall, including the gable and the wall below it.

Hip roof type of roof where all sides slope downwards to the walls

A hip roof, hip-roof or hipped roof, is a type of roof where all sides slope downwards to the walls, usually with a fairly gentle slope. Thus a hipped roof house has no gables or other vertical sides to the roof.

Wall dormer dormer which aligns with the wall plane

A wall dormer is a dormer whose facial plane is integral with the facial plane of the wall that it is built into, breaking the line of the eaves of a building.


The word dormer is derived from the Middle French dormeor, meaning "sleeping room", [10] as dormer windows often provided light and space to attic-level bedrooms. [2]

Middle French is a historical division of the French language that covers the period from the 14th to the early 17th centuries. It is a period of transition during which:

One of the earliest uses of dormers was in the form of lucarnes, slender dormers which provided ventilation to the spires of gothic churches and cathedrals. An early example are the lucarnes of the spire of Christ Church Cathedral, Oxford.

English Gothic architecture architectural style in Britain

English Gothic also known as Perpendicular Gothic is an architectural style originating in France, before then flourishing in England from about 1180 until about 1520.

Christ Church Cathedral, Oxford Church in Oxfordshire, United Kingdom

Christ Church Cathedral is the cathedral of the diocese of Oxford, which consists of the counties of Oxfordshire, Buckinghamshire and Berkshire. It is also the chapel of Christ Church at the University of Oxford. This dual role as cathedral and college chapel is unique in the Church of England.

Dormer windows have been used in domestic architecture in Britain since the 16th century. [11] Dormer windows were popularised by French architect Francois Mansart, who used dormers extensively in the mansard roofs he designed for 17th-century Paris. [12]

Today dormers are a widespread feature of pitched roof buildings.

Requirements for permission to construct

In some localities, permission must be sought for construction of dormers and other features. In England and Wales, the General Permitted Development Order states classes of development for which such planning permission is not required. [13] Such rights are only applicable outside conservation areas, national parks, Areas of Outstanding Natural Beauty or The Broads. [13] Dormers may introduce imbalance in the street scene and be seen as inappropriate within the local setting of streets and buildings. [14]


Dormers are popular in Ulster. [15] and commonly used to create extra space when a loft is converted into a habitable room [16]

See also

Related Research Articles

Bungalow type of building, originally developed in the Bengal region in South Asia, but now found throughout the world

A bungalow is a type of building, originally developed in the Bengal region of the Indian subcontinent. The meaning of the word bungalow varies internationally. Common features of many bungalows include verandas and being low-rise. In Australia, the California bungalow associated with the United States was popular after the First World War. In North America and the United Kingdom, a bungalow today is a dwelling, normally detached, that may contain a small loft. It is either single-story or has a second story built into a sloping roof, usually with dormer windows.

Mansard roof four-sided gambrel-style hip roof

A mansard or mansard roof is a four-sided gambrel-style hip roof characterized by two slopes on each of its sides with the lower slope, punctured by dormer windows, at a steeper angle than the upper. The steep roof with windows creates an additional floor of habitable space, and reduces the overall height of the roof for a given number of habitable stories. The upper slope of the roof may not be visible from street level when viewed from close proximity to the building.

Tented roof type of polygonal hipped roof with steeply pitched slopes rising to a peak

A tented roof is a type of polygonal hipped roof with steeply pitched slopes rising to a peak. Tented roofs, a hallmark of medieval religious architecture, were widely used to cover churches with steep, conical roof structures.

Spire light

Spire light, the term given to the windows in a spire which are found in all periods of English Gothic architecture, and in French spires form a very important feature in the composition.

This page is a glossary of architecture.

Mono-pitched roof roof consisting of a single sloping surface

A mono-pitched roof, often referred to as a pent roof, shed roof, lean-to roof, and/or skillion roof, is a single-sloped roof surface, often not attached to another roof surface. This is in contrast to a dual-pitched roof, also known as a gabled roof, which is pitched in two different directions.

George Cobb House historic house in Massachusetts, United States

The George Cobb House is a historic house located at 24 William Street in Worcester, Massachusetts. Built about 1875, it is a well-preserved and little-altered example of late Gothic Revival architecture. The house was listed on the National Register of Historic Places on March 5, 1980.

Normandy Grange

Normandy Grange is located along NY 9D north of Garrison, New York, United States. It is a Norman-style house and farm complex built in the early 20th century.

Gable roof may have eaves or parapet; no rake overhanging

A gable roof is the classic, most commonly occurring roof shape in those parts of the world with cold or temperate climates. It consists of two roof sections sloping in opposite directions and placed such that the highest, horizontal edges meet to form the roof ridge. The design of this type of roof is achieved using rafters, roof trusses or purlins. The pitch of the roof and the height of the gutters can vary greatly.

North Grove Street Historic District

The North Grove Street Historic District is located along the north end of that street in Tarrytown, New York, United States. It consists of five mid-19th century residences, on both sides of the street, and a carriage barn. In 1979 it was listed on the National Register of Historic Places.

Central-passage house

The central-passage house, also known variously as center-hall house, hall-passage-parlor house, Williamsburg cottage, and Tidewater-type cottage, was a vernacular, or folk form, house type from the colonial period onward into the 19th century in the United States.

Jackson Park Town Site Addition Brick Row building in Wyoming, United States

Jackson Park Town Site Addition Brick Row is a group of three historic houses and two frame garages located on the west side of the 300 block of South Third Street in Lander, Wyoming. Two of the homes were built in 1917, and the third in 1919. The properties were added to the National Register of Historic Places on February 27, 2003.

Nappanee Eastside Historic District

Nappanee Eastside Historic District is a national historic district located at Nappanee, Elkhart County, Indiana. The district encompasses 138 contributing buildings in a predominantly residential section of Nappanee. It was developed between about 1880 and 1940, and includes notable examples of Italianate, Queen Anne, Colonial Revival, and Prairie School style architecture. Located in the district are the separately listed Frank and Katharine Coppes House and Arthur Miller House.

The San Juan Historic District in San Juan, New Mexico is a 23 acres (9.3 ha) historic district which was listed on the National Register of Historic Places in 1988. The listing included 14 contributing buildings and two non-contributing buildings.


  1. "Definition of dormer". Retrieved 23 May 2016.
  2. 1 2 Barr, Peter. "Illustrated Glossary - 19th Century Adrian Architecture". Retrieved May 23, 2016.
  3. "Dormer Types: Gabled". Retrieved 25 May 2016.
  4. "Dormer Types: Hipped". Retrieved 25 May 2016.
  5. Dictionary of Architecture & Construction, C.M.Harris.
  6. "Eyebrow". Retrieved 2012-09-28.
  7. A Visual Dictionary of Architecture. Francis D.K. Ching
  8. Gitlin, Jane (2003). Capes: Design Ideas for Renovating, Remodeling, and Building New. Newtown, CT: Taunton. p. 44. ISBN   9781561584369.
  9. Bradley, Simon, ed. (2010), Pevsner's Architectural Glossary, Yale University Press, p. 80, ISBN   978-0-300-16721-4
  10. "Etymology of "dormer"". Online Etymology Dictionary. Retrieved 23 May 2016.
  11. "Traditional Dormer Windows: Design Guide". Tewkesbury Borough Council. Retrieved 23 May 2016.
  12. Maddox, Nathania. "ABOUT DORMERS". Retrieved June 17, 2015.
  13. 1 2 "Permitted Development Rights". Planning Portal website. . Retrieved 14 October 2013.
  14. "Policy advice note: Garden city settlements" (PDF). TCPA. October 2008. Retrieved 14 October 2013.
  15. The Bedside Book of Dormers and Other Delights: A Pictorial Guide to Traditional Architectural Details in Ulster
  16. About Loft Conversions (2008). "Dormer Loft Conversion", About Loft Conversions.