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Dormer Roof

Dormer Roof Types and Characteristics

How to make a more usable and livable space by constructing a dormer roof. Discover various Types and advices to guide you troughs a dormer roof project.

Constructing a dormer roof is the best way to bring natural light and air into attic spaces. Let’s explore the types of dormer roofs and factors to consider in order to leverage all the benefits adding architectural character to the building you are designing.

Dormer Roof | Render created with Edificius

Dormer Roof | Render created with Edificius

What is a Dormer Roof

A dormer roof is an architectural solution designed to promote illumination and air circulation in attic spaces. It consists of a small or medium-sized space with a window that allows better lighting and effective air exchange. The components that make it up and characterize it. They may include:

  • an outward opening (window or French door of variable size and type) overlooking the building’s roof;
  • a small roof covering the space, consisting of one or more slopes with variable inclinations and shapes;
  • vertical enclosures that connect the dormer’s slopes to the main roof.
Dormer Roof

Dormer Roof

This type of structure has long been widespread, especially in historical homes in northern Europe. In recent years, it has also appeared on new construction buildings’ roofs or on recently constructed buildings to reclaim the living space of non-habitable attics, adding rooms to existing residence.

Constructing a dormer allows you to expand the space, obtaining additional habitable room to replace small storage spaces or even unusable spaces due to insufficient minimum height.

Difference Between Dormer Roof and Skylight

Dormer roofs and skylights are both architectural elements designed to introduce natural light into buildings, but they differ in their shape, position, and purpose.

A dormer roof is an architectural structure usually built on sloping roofs, typically consisting of two small slopes (less commonly a single flat or sloping slope or a vaulted structure) emerging from the roof. It aims to connect the windowed vertical wall of the dormer itself with the building’s roof.

The brightness of the interior spaces obtained is comparable to that generated by a normal front-facing window.

Habitable Attic | Section

Habitable Attic | Section

The purpose is to have a more usable interior space by creating open windows to the outside and additional volumes that also allow for an increase in usable internal height, recovering even less livable and inadequately high spaces. Attic spaces can thus be used as bedrooms, studies, or even as independent real estate units when space and health and hygiene requirements allow.

Unlike dormer roofs, skylights are simple windows integrated into the slope of the roof and positioned according to its inclination. Installable on flat roofs as well, they do not alter the shape and characteristics of the roof and do not affect the volume of internal spaces. Additionally, they allow the entry of light zenithally and not horizontally, as is the case with dormer roofs and front-facing windows.

Skylight Render created with Edificius

Skylight Render created with Edificius

The skylight was initially designed to provide light, air circulation and accessibility to the roof. Especially in areas not intended for residential use. Only in contemporary architecture, with the development of technologies that allow fixtures with high thermal-acoustic performance and water tightness, it has become an element used in residential construction. Even alongside vertical windows, roof windows are loved for their diffused brightness, comfort and well-being conditions, as well as for the direct contact they generate with the surrounding environment. They have the advantage of uniformly and deeply illuminating every space: compared to a dormer roof or a vertical window, a roof window brings in up to three or four times more light.

Playing with dormer roofs and skylights allows you to create spaces with great character, very bright and harmonious, both in traditional and contemporary design structures.

The use of dormer roofs, unlike skylights, can be very helpful in the design phase to increase the average height of the space and to achieve attic’s habitability. If you are interested in this topic, I recommend reading also “Project for the Recovery of an Attic: Ideas and Example.”

Dormer Roof | Render created with Edificius

Dormer Roof | Render created with Edificius

Types of Dormer Roofs

As we have seen, dormer roofs are an ingenious solution to increase natural light inside buildings. Strategically positioned on roofs, they allow light to enter interior spaces, reducing dependence on artificial light and contributing to energy savings. It is essential to carefully evaluate the angle, dimensions and type of dormer roofs to maximize light efficiency and to minimize direct heat entry during the warmer months.

Dormer roofs can be classified based on the materials used for the structure (masonry, wood, steel, reinforced concrete, etc.) or based on the shape of the small slopes that characterize them. Based on their shape, we can talk about different types of dormer roofs:

  • pavilion, consisting of a roof with three or more slopes inclined toward a single central point;
  • gable, triangular in shape without side walls, offering a simple solution to implement;
  • doghouse dormer, composed of a small roof with two sloping slopes emerging from the main roof and vertical closing walls;
  • shed dormer, characterized by a single sloping roof, usually with a lower slope than the main roof. It extends along the roof slope, creating additional interior space and providing lighting and ventilation;
  • oculus, featuring a circular or elliptical window, highly decorative and common in French architecture, often positioned strategically to maximize light and importance to the facade;
  • trapezoidal, with a rectangular plan and two oblique sides to make the most of attic space;
  • barrel vault, characterized by a vaulted roof and a vertical wall that follows its curvature. Adding therfore a distinctive architectural element and significantly increasing the internal height of the attic;
Dormer Roof

Dormer Roof

Choosing one type of dormer roof over another depends on the style of the home, local regulations. But also on brightness and internal space utilization conditions you want to achieve.

Using 3D modeling software, you can recreate the volume of the project building and automatically add all the types of dormer roofs mentioned. The software has a parametric “dormer” object that facilitates and automates 3D modeling. Simply choose the type of dormer, enter the dimensions (height, width, slope, etc.) and the model is complete.

This makes it easier to carefully evaluate which architectural typology suits your project best, both in terms of shape and functionality of internal spaces. By automatically generating infinite sections from the 3D model, you can check internal heights ensuring that the space is safely usable and in compliance with the habitability, health and hygiene indices defined by regulations (minimum height, average height, aero-illumination ratio, etc.). Real-time or virtual reality model navigation and renders, on the other hand, help you choose the style, materials, colors and shapes that best suit your ideas and your client’s requests.

To create the 3D model of your project building, complete with dormer roofs, watch this short video tutorial.

 

 

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