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Light Roof asks you to design an enclosed home, daylit only from above

With the housing crisis high on all agendas, a competition to design a house daylit only from above is timely and topical

In this project, Keylite Roof Windows give views of the changing sky that animate the interior.
In this project, Keylite Roof Windows give views of the changing sky that animate the interior.

As our cities densify, and straightforward sites become ever more scarce, attention turns to backland plots and enclosed courtyards that – with a good dose of persistence and architectural ingenuity – might just accommodate a house. Access is often tricky, as is the negotiation of numerous party walls, but the greatest challenge of such landlocked sites is the availability of daylight, fresh air and views. Hemmed in on all sides, often overlooked and overshadowed, they receive light only from above, which must be brought down through the building by skilful manipulation of the roof and the section.

In recent years, the architects of some exceptional projects have turned such constraints into opportunities to make powerful and exceptional interiors shaped by light. Limited access to daylight underlines its value, driving the arrangement of spaces and the character of the interior. Shadow patterns and views of the sky make features of the movement of the sun and changes in the weather.

The RIBAJ Light Roof competition, in partnership with Keylite Roof Windows, asks entrants to imagine a generous family home for a compact site that is enclosed on all sides, so that the only access to daylight is from the sky directly above. Take an existing or imagined site – a backland plot, a courtyard at the centre of a larger building, or the ground beneath a private garden – and create spaces with a quantity and quality of daylight suited to all parts of domestic life: sleeping, working, cooking and eating, relaxing and entertaining. The task is not merely to ensure adequate illumination, but to add character and interest to diverse interior spaces through direct, borrowed, filtered or reflected toplight. 




The house should be arranged over more than one storey. Atria and internal lightwells may be used, but should not account for more than 20% of the site area. 
Consideration should be given to how views of the sky and changing weather might enrich the experience of living in the house. 
Designs should use the configuration of plans and sections, and the type and location of openings in the roof, to create daylight conditions that vary throughout the building and over time. The means might include, but are not limited to:

  • Atria, windows onto lightwells and internal courtyards lanterns and oculi
  • Skylights and operable roof windows
  • Reflective light tubes, mirrors and light shelves
  • Blinds and shading devices

Judges will look for imaginative but workable schemes which take limited access to daylight as an opportunity to explore the potential of toplight, borrowed daylight and sky views in a domestic setting. 
The winning proposal will: 

  • Be spatially innovative
  • Relate the form and architectural character of the building to the sources of available light
  • Turn the limitations of the site into an architectural advantage

Entries must include the following:

  • An entry form, including a text of no more than 400 words, describing the approach to daylighting
  • Drawings laid out on no more than two A3 sheets, supplied as pdfs. These are to include: 
  • Floor plans, including north point
  • A key section
  • 3D axonometric or perspective images that convey the nature of the proposition
  • Lighting and ventilation, and the quality of the spaces envisioned
  • Any supplementary images you may consider helpful to explain the proposition

Deadline: 14.00 hours, Tuesday 14 September

Winning and commended entries will be published on and in the print edition of the RIBA Journal. There is a cash prize of £2000 for the winning entry, and £500 each for three commended entries. 

Lightroof is produced is association with Keylite windows

Please send any enquires to


1. Competition promoter

The competition is being run by the RIBA Journal in conjunction with Keylite Roof Windows.

2. Eligibility

The competition is open internationally to architects and early career professionals (part 1, part 2 or studying for part 3).

No member or employee of the promoting body, the evaluation panel, or any partner, close associate or employee of them is eligible to compete or assist a competitor.

3. Competition format

This is a single stage competition.

4. Judges’ decision

The judges’ decision as to winners and commendations is final. Judges are looking for an overall winner and may also award commendations. Judges reserve the right to declare no winners if entries are of insufficient quality.

5. Evaluation panel

The evaluation panel is expected to be composed of architects and a representative from Keylite Roof Windows, and chaired by a member of the editorial team at the RIBA Journal.

In the event of an evaluation panel member being unable to continue to act through illness or any other cause, the RIBA reserves the right to appoint an alternative panel member.

6. Competition timetable

The anticipated programme, which may be subject to variation, is as follows:

Competition launch 

3rd June 2021

Submission deadline 

2 pm. 14th September 2021

Evaluation of designs with panel and winners agreed 

29th September 2021

Email notification to winners 

w/c 22nd November 2022

Result announced on

w/c 22nd November 2022 


7. Disqualification

Submissions shall be excluded from the competition:

  • If an entrant improperly attempts to influence the decision
  • If received after the latest time stated under the Submission method (below)
  • If, in the opinion of the Evaluation Panel, it does not fulfil the requirements of the competition brief
  • If any of the mandatory requirements of the brief and conditions are disregarded.

8. Submission requirements

There are two elements to the submission:

  • Completed entry form
  • Images on two A3 sheets, supplied as pdfs

9. Evaluation criteria

  • High quality writing
  • Engagement
  • Clarity
  • Currency of choice of subject

10. Notification of result / publication and publicity

The competition results will be published after all entrants have been notified.

Entrants must not release their entries for publication to any third parties until after the result has been officially announced and permission has been granted from the RIBA. Entrants should note that by entering the competition they are expected to honour the request for confidentiality.

The RIBA reserves the right to publicise the competition, any entry, and the result in any promotional activity, including all social media channels.

You and your collaborators grant to the Royal Institute of British Architects permission to reproduce the material supplied in all formats, in all media and on all platforms in perpetuity, in whole or in part without payment.

11. Copyright

The ownership of copyright will be in accordance with the Copyright, Designs and Patents Act 1988 – ie copyright rests with the author of the submitted text and images.

12. Post competition

Winning and commended entries will be published on and may also be published in the print edition of the RIBA Journal.

13. Enquiries

All enquiries relating to the competition should be directed to:

14. Data

Data will be held by RIBA for the purposes of recording participation in the competition. The data will be kept throughout the duration of the competition for the purpose of contacting entrants with updates for the competition. This information will not be shared with any third party without the express and prior consent of the author. Read the RIBA’s privacy policy.


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