dormer

An English street showing gable dormer windows

A dormer is a structural element of a building that protrudes from the plane of a sloping roof surface. Dormers are used, either in original construction or as later additions, to create usable space in the roof of a building by adding headroom and usually also by enabling addition of windows.^[1]

Often conflated with the term "dormer", a dormer window is a window set into the dormer. Like skylights, dormer windows are a source of light and ventilation for top floors, but unlike skylights (which are flush with the roof surface) they also increase the amount of headroom in the room and allow for more usable space.

A blind dormer or false dormer is a dormer that can only be seen from the outside of the house: it is roofed off on the inside, and does not provide any extra space or light. These are often used to make the house appear more impressive.

A dormer is often one of the primary elements of a loft conversion.

Types

A link dormer

A shed dormer

The main types of dormer are:

• Gable fronted dormer: the front of the dormer rises to a point at the ridge of the dormer roof. Also known as a dog-house dormer.
• Hipped roof dormer: the roof slopes back from front of structure to a point farther back, or, a dormer with a hip roof.
• Flat roof dormer: the roof of the dormer is flat.
• Shed dormer: A dormer (window) whose eave line is parallel to the main roof eave line.^[2] Shed dormers can provide more attic space and head room than gable dormers, but cannot be the same pitch as the main roof and may therefore require different roof sheeting. Often used in gable-roofed homes, a shed dormer has a single-planed roof, pitched at a shallower angle than the main roof.
• Wall dormer: A dormer whose face is coplanar with the face of the wall below, breaking the line at the cornice of the building.
• Eyebrow or eyelid dormer "A low dormer on the slope of a roof. It has no sides, the roofing being carried over it in a wavy line." ^[3] The bottom of an eyebrow dormer is flat and the top is curved.
• Link Dormer A large dormer that houses a chimney or joins one part of a roof to another.^[4]
• Bonnetted Dormer. Arched roof of dormer, rounded shape when viewed from front. Popular in Victorian homes, especially in certain areas, like the Southcott-style row-houses called Jellybean Row in St. John's, Newfoundland.

Popularity

Ireland

During the Irish property bubble the popularity of dormers in Ireland soared immensely; they were often fitted to new multi-storey residential homes as well as in smaller houses such as those found in ghost estates. Retrofitting of dormers, however, remained uncommon.

Disadvantages

Improperly constructed dormers are prone to leaks and give rise to expensive repairs.

See also

• Bungalow

References

Wikimedia Commons has media related to: Dormer windows

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