Dormer window
A dormer is a small roofed structure that projects outwards from the main pitched roof of a building. Dormers can be included in the original construction of a building or added on subsequently.
Dormers are becoming more common in homes as they can help create extra headroom in spaces that may otherwise be too small or too low for habitation. They enable the creation of rooms in the roof or loft without needing to construct a new storey. Dormers will typically have dormer windows set into them to allow light and ventilation.
There are a number of different types of dormers including:
Box roof/flat roof: The plane of the roof is horizontal. This type of dormer provides the most space and floor area inside the building.
Gable: These have a gable roof, with the front of the dormer being flat with a pitched roof and vertical sides.
Hip roof: The roof comprises of three sloping panels that meet at the ridge.
Arched/eyebrow: This is similar to the hipped dormer but has an arch or curve which allows it to blend in to the existing roof.
The insertion of dormer windows as part of a loft conversion does not normally require planning permission. However, If the roof space is altered or extended and it exceeds specified limits and conditions, permission may be necessary. It may also be necessary to obtain permission within conservation areas, National Parks, Areas of Outstanding Natural Beauty or the Broads, or if the building is listed.
Dormer windows may require building regulations approval.
[edit] Related articles on Designing Buildings Wiki.
Featured articles and news
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.
The Warm Homes Plan details released
What's new and what is not, with industry reactions.
Could AI and VR cause an increase the value of heritage?
The Orange book: 2026 Amendment 4 to BS 7671:2018
ECA welcomes IET and BSI content sign off.
How neural technologies could transform the design future
Enhancing legacy parametric engines, offering novel ways to explore solutions and generate geometry.
Key AI related terms to be aware of
With explanations from the UK government and other bodies.
From QS to further education teacher
Applying real world skills with the next generation.
A guide on how children can use LEGO to mirror real engineering processes.
Data infrastructure for next-generation materials science
Research Data Express to automate data processing and create AI-ready datasets for materials research.
Wired for the Future with ECA; powering skills and progress
ECA South Wales Business Day 2025, a day to remember.
AI for the conservation professional
A level of sophistication previously reserved for science fiction.
Biomass harvested in cycles of less than ten years.
An interview with the new CIAT President
Usman Yaqub BSc (Hons) PCIAT MFPWS.
Cost benefit model report of building safety regime in Wales
Proposed policy option costs for design and construction stage of the new building safety regime in Wales.
Do you receive our free biweekly newsletter?
If not you can sign up to receive it in your mailbox here.


























Comments
We appreciate your efforts in writing such a detailed post on Dormer Window, that
would be helpful for every homeowner. The window is done with proper planning and attention to make your house outlook nice.