All About Dormers and Their Architecture

Red roof with dormer


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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 may be built into the roof or a wall and they come in many shapes and sizes. The kind of roof on the dormer 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, so you should carefully consider when and where to add them.

Take a look a these examples 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." The gable above the dormer is called the dormer head, and it is often in the shape of a pediment.

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

  • 02 of 16

    Why Add a Dormer?

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

    Phillip Spears/Getty Images

    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.


    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. False dormers may be out of proportion—either too large or too small—and look unnatural. The artificiality of planned communities like Celebration, Florida is due, in part, to this type of fake architectural detail.

  • 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 an older large home to accommodate live-in domestic workers.

  • 04 of 16

    Bathroom Space

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

    Nicholls Alistair/Getty Images

    Besides extra sleeping quarters, the additional interior space created by a dormer took a different turn with the invention of indoor plumbing. Bathrooms require headspace for standing, and a dormer allows this height to be added above a toilet, sink, or bathtub. This allows an attic space to have a bathroom for a primary suite or as an additional bathroom for the house.

    About This Term: Primary Suite

    Many real estate associations, including the National Association of Home Builders, have classified the term "Master Bedroom" (or "Master Suite") as discriminatory. "Primary Bedroom" is the name now widely used among the real estate community and better reflects the purpose of the room.

    Read more about our Diversity and Inclusion Pledge to make The Spruce a site where all feel welcome.

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  • 05 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. The windows can match the other windows of the house, or you may make the dormer window fancier, such as with colored glass or a non-traditional shape. The windows may be fixed or they can be designed to open to allow for ventilation.

  • 06 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 midcentury building boom. There is nothing fancy with these additions—simple gable roof dormers functioned to add light, air, space, and symmetry to the American home. A gable roof is formed by two sloping sections meeting at the top ridge, forming a triangular shape for the top of window wall of the dormer. The walls of the dormer that extend downward from the gable roof are vertical.

  • 07 of 16

    The Shed Roof Dormer

    Craftsman home with dormer


    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

    J.Castro/Getty Images

    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.

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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

    Andreas Secci/Getty Images

    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 more elegant. It often mimics the hipped roof of the house itself. A hipped roof has four sloping sides that come together in a peak, rather than a gable which has just two sloping sides.

  • 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 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

    David Chapman/Getty Images

    Dormers are common features of Second Empire style homes. François Mansart (1598–1666) 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.

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  • 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

    English country manor


    Karol Franks / Getty Images 

    Windows are part of an architect's toolbox. In this Southern California house, the renowned architect Paul Williams (1894–1980) combined different window types in an aesthetically pleasing way. A shed dormer and a wall dormer breaking through the roofline 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

    Prefab Dormers

    A prefab dormer is installed with a crane

    Jaap Hart/Getty Images

    Not everyone has the funds to hire an architect the likes of Paul Williams to design a home. Not to worry. Adding a prefabricated dormer to an existing home is an exciting adventure. Consider the challenge, but do your homework. This is not a simple do-it-yourself job as it requires skills in roofing and installing roof flashings, or otherwise you will have leaks. You will need to choose a size of dormer that fits well with your house, draw up a plan, and get the required building permits. You will be removing the roofing in the area of the dormer, so you must be prepared to shield it with a waterproof tarp in case of rain. After opening the roof, you can install a prefab dormer and the flashing needed to keep your installation waterproof.

  • 16 of 16

    The Eyes of Your House

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

    Keep in mind that essentially dormers are windows, and glazing is two-faced. A dormer allows light in and gives you a view out of the room. But it also allows neighbors to look in and changes the appearance of your house from the curb. Dormer windows can make your home come alive. Just look at those eyes.

Article Sources
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  1. Fleming, John, Honour, Hugh, and Pevsner, Nikolaus. "Dormer Window." The Penguin Dictionary of Architecture. Third Edition, Penguin, 1980, pp. 96-97

  2. Baker, John Milnes. "American House Styles: A Concise Guide." AIA, Norton, 1994, p. 170