All About Dormers and Their Architecture

Detail low-angle view of a dormer window with gable roof, shingle siding, and 16 glass panes

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A dormer is a window that is typically set vertically on a sloping roof. The dormer has its own roof, which may be flat, arched, hipped, pointed, or ornamented. Dormer windows come in all shapes and sizes. They can be roof dormers or wall dormers. They can have different kinds of roofs, that may complement the larger roof or other architectural details of the house. Dormers can add beauty and curb appeal to your home, or they can end up making your house look ridiculous. The following photo gallery of dormers will help you make your own decisions. This series of photographs shows many types of dormers from different architectural periods throughout history.

  • 01 of 16

    The Eyes of a Dwelling

    Seven dormers and three chimneys on a 16th century Welsh roof

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    The dormers shown here, each having a gable roof, are from a pub called The Myddelton Arms. Located in the Medieval town of Ruthin in northern Wales, these notable and popular dormers from the 16th century are known as "the eyes of Ruthin."

    For centuries, windows have been known as "the eyes" of a dwelling. Like a chimney, roof dormers are not part of the roof but stick through the roof. Some dormers, called wall dormers, stick through the edge of the roof at the cornice.

    Essentially, dormers are "glazed structures," meaning they are windows. In fact, they are sometimes called lucarne, a French word for "skylight."

    To install a dormer in your home, call a window specialist and master carpenter instead of a roofer.

    More Definitions of Dormer

    " dormer a glazed structure with its own roof that projects from the main roof of a building or is a continuation of the upper part of a wall so that the eave line is interrupted by the dormer." — John Milnes Baker, AIA
    " Dormer Window. A window placed vertically in a sloping roof and with a roof of its own. The name derives from the fact that it usually serves sleeping quarters. Also called LUCARNE. The gable above a dormer window is often formed as a pediment and called a dormer head." — The Penguin Dictionary of Architecture
  • 02 of 16

    Why Add One?

    One story house near street, full width front porch, gable dormer

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    Dormers can have exterior and interior beauty and appeal.

    On the inside, what may be dark, attic space can become habitable with a dormer window. An additional bathroom can be enlarged by a dormer tucked into a large bedroom. Besides additional space for a home, natural light and ventilation can make interiors more inviting and healthier.

    From the outside, a dormer can define certain house styles—Neo-colonial and Colonial Revival, Stick Style, Chateauesque, Second Empire, and the American Foursquare are all house styles that generally include a dormer in their designs. Also, a dormer can give a horizontally-oriented house a sense of height, especially if the house is situated very close to a street. When designed correctly, a dormer can accentuate the architectural details in the body of the house—Victorian scrollwork, pediments, and even window likeness and symmetry can be enhanced by a like-minded dormer.

    Avoid the False Dormer

    Like cosmetic cupolas that sit without function atop a roof, the false dormer is a growing trend, especially in new commercial real estate. In an attempt to mimic a certain hometown colonial style of architecture, dormer units are attached to the roof without breaking through the roof. Fake dormers are often ridiculously out of proportion—either too large or too small—and they look silly because they appear so unnatural. The artificiality of planned communities like Celebration, Florida is due, in part, to this type of fake architectural detail. If you're tempted by this trend, ask yourself this—who are you trying to fool?

  • 03 of 16

    Dormer Comes From Dormitory

    Interior of a double-window dormer, bedroom with angled roofline

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    The word "dormer" comes from the same root as the word "dormitory," both coming from the Latin word dormitorium, which means a place for sleeping. It should come as no surprise, then, that attic spaces are often converted into extra bedrooms with a dormer to cross-ventilate with a gable window. Original dormers may have been built into your own large home to accommodate live-in domestic workers.

  • 04 of 16

    Add a Bathroom

    small toilet and sink beneath 9-paned windows of a dormer interior

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    Besides extra sleeping quarters, the additional interior space created by a dormer took a different turn with the invention of indoor plumbing.

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  • 05 of 16

    Gable Dormers

    Cape Cod style house with two dormers on the house and one over the garage door.

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    Dormers were especially popular in the 1950s Cape Cod style home designs of America's mid-century building boom. Nothing fancy with these additions—simple gable roof dormers that functioned as planned, adding light, air, space, and symmetry to the American home.

  • 06 of 16

    Inside Space and Window Options

    Teenage girl with digital tablet in dormer alcove window seat

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    The amount of light and ventilation afforded by a dormer is a function of the imagination. Do the windows have to match the other windows of the house? Can a dormer window be fancier? Colored glass? Nontraditional in shape?

  • 07 of 16

    The Shed Roof Dormer

    Long, low dormer atop a California Craftsman home, above a front porch with wooden door and vertical porch windows

    Thomas Vela/Getty Images

    After the gable roof dormer, probably the second most popular roof shape is the shed dormer. Often taking a pitch similar to the roof of the house, the shed dormer can accommodate small or large windows in a narrow or elongated width. Shed dormers are very common in Craftsman style homes and bungalows.

  • 08 of 16

    The Extended Shed Dormer

    Typical American home with four-window dormer along the length of the roof facade

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    Perhaps the most common type of shed dormer is the one extending nearly the full width of a house. In the front or back, this type of shed dormer extends interior space without adding to the footprint of the building. It has been very popular since the 1960s to the present time.

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  • 09 of 16

    Flat Roof Dormer on Modern Building

    Flat roof dormers with vertical panes project from a nontraditional sloped roof of a modern building facade

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    An extension of the shed roof dormer is the flat roof dormer. In this modern building in Germany, you can see that dormers are hardly an old-fashioned idea. Postmodern architects often take traditional architectural details and turn them on their heads.

  • 10 of 16

    The Hipped Roof Dormer

    Large Spanish-inspired home, arched windows on the first floor, 6 over 6 windows on the second floor, and a dormer with small vertical windows on the red roof over similar windows on the second floor

    J.Castro/Getty Images

    The hipped roof dormer is slightly less popular than gable and shed dormers, but it's slightly more elegant. It often mimics the hipped roof of the house itself.

  • 11 of 16

    Arched Eyebrow Dormer

    view of second floor and roof facade, three-sectioned arched eyebrow windows on a Thatched Roof between two enormous chimneys with chimney pots

    Gillian Darley/Getty Images

    For centuries, the playful British have incorporated small arched windows into their cottage architecture. As these windows enable more light than space to enter interiors, eyebrow windows are often considered more of a window than a dormer. The glazed slits can become very narrow and visually seductive.

  • 12 of 16

    Mansard Roof Dormers

    Detail of ornate gabled dormer windows from the steep slope of a mansard roof

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    Dormers are common features of Second Empire style homes. François Mansart (1598 to 1666) modified the gambrel roof by making the sides steeper and inserting windows. The French architect had invented what became known as the Mansard roof, a popular roof style. The windows breaking through the Mansard roof are some of the earliest examples of dormer windows.

    Even a more modern building with a Mansard roof likely will have dormers—sometimes both wall dormers (through the cornice) and roof dormers. The elegant and regal Biltmore Estate in Asheville, North Carolina exemplifies the 19th-century Mansard roof dormer on a Chateauesque style large home.

    Continue to 13 of 16 below.
  • 13 of 16

    Through-The-Cornice Dormers

    House where the dormers split the line of the roof, the bottom of the window is on the siding facade and the top gable protrudes from the roof

    J.Castro/Getty Images

    Most dormers are roof dormer windows—that is, the structure's roof surrounds the dormer as if it were a skylight. Accounting for snow loads in certain climates, constructing roof dormers is relatively straightforward in both original design and renovations. 

    A more complicated and some would argue a more elegant design is the dormer that is built through the cornice or the roof's edge. Also called "wall dormers," these "through-the-cornice" dormers are common in grand mansions and upscale neighborhoods.

  • 14 of 16

    An Architect's Eye for Windows

    Different window varieties in a mansion home

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    Windows are part of an architect's toolbox. In this Southern California house, the renowned architect Paul Williams (1894 to 1980) combined different window types in an aesthetically pleasing way. A shed dormer and a wall dormer breaking through the roof line are added to more typical windows and an oriel window to make this English Manor style "cottage" look like a simple country home inside and out.

    A good architect will have the education and training to envision design patterns that work for your house.

  • 15 of 16

    Installing Prefab

    A prefab dormer is installed with a crane

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    Not everyone has the funds to hire an architect the likes of Paul Williams to design your home. Not to worry. Adding a prefabricated dormer to an existing home is an exciting adventure. Consider the challenge, but do your homework.

  • 16 of 16

    The Eyes of Your House

    Two eyebrow window dormers in a red tile roof
    Marco Cristofori/Getty Images

    Remember that essentially dormers are windows, and glazing is two-faced. Whether you are looking out or the neighbors are looking in, dormer windows can make your home come alive. Just look at those eyes.


    • "Fleming, John, Honour, Hugh, and Pevsner, Nikolaus. "Dormer Window," The Penguin Dictionary of Architecture. Third Edition, Penguin, 1980, pp. 96-97
    • Baker, John Milnes. American House Styles: A Concise Guide. AIA, Norton, 1994, p. 170