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BHSM LLP | Ireland

Blind(sided) by the Light – Early resolution of disputes key to urban development


We all want our homes and workplaces to be bright and airy spaces and to preserve as much natural light as possible. However, development in urban areas will inevitably lead to some interference with flows of light to adjacent buildings. In this article, James Lawless & Michelle McArdle consider how best to balance Rights to Light with the objectives of enhanced urban development.


Given Ireland’s ever-increasing demand for housing, the Government has accepted that “we need to build inwards and upwards, rather than outward” by pursuing a “compact urban form, facilitated through well-designed high-density development[1].  The Government’s Housing for All policy identifies more intensive use of urban land as key to delivering on the target of 300,000 new homes by 2030.

However, both the Government and the construction industry have identified a myriad of issues which render development sites unviable, notwithstanding a grant of planning permission. As a result of these viability issues between 70,000 – 80,000 grants of planning permissions have not been activated, 40,000 of which are in the Dublin area[2]. Disputes over Rights to Light have become one issue affecting viability and have considerable potential to block high-density development.

Infringement of Right to Light

A Right to Light protects the right for specific openings of a building (usually windows) to receive natural light for the benefit of the building’s interior. If natural light passes over lands adjoining an existing building, any new structures on those adjoining lands must not, in principle, obstruct (to a material degree) the light being received by the openings of the existing building.

Any obstruction or interference with existing flows of light must however constitute a nuisance before infringement of a Right to Light can be claimed. A minor or insignificant diminution in the flow of light will not result in a breach of Rights to Light. Whether or not a nuisance has arisen will depend on the extent to which light has been diminished and the effects of same on the use and enjoyment of a building’s interior. The Courts have defined nuisance in this context as:

“a substantial privation of light, sufficient to render the occupation of the house uncomfortable according to the ordinary notions of mankind, or to prevent the plaintiff from carrying out his accustomed business on the premises as beneficially as he had formerly done[3].

What constitutes a diminution of light that is ‘uncomfortable according to ordinary notions of mankind’ is not a legally defined concept and while this creates a degree of uncertainty, legal experts believe it gives the Courts useful flexibility in deciding individual disputes.

In addition to the legal concept of nuisance, there are scientific ways to measure the diminution of light such as the use of 3-D representations and measurement of lumens using Waldram diagrams[4]. For example, modern research suggests that between 10-25 lumens of light is the minimum light required to carry out general clerical tasks within an office space. These modelling tools should assist in attempts to prove (or disprove) that a Right to Light has been infringed.

Planning Process

A High Court injunction is the strongest weapon to defend a Right to Light claim. If an injunction is successful, it could result in Court orders to halt a proposed development, to demolish all or part of a newly completed development or result in an award of damages. In circumstances where developers are ready to mobilise a construction project after the planning process has concluded (and planning permission granted), the prospect of a last-minute High Court injunction is a nightmare scenario in circumstances where adjoining owner did not raise Right to Light issues during the planning process.

Significantly, a grant of planning permission does not guarantee that a proposed development is immune from Right to Light challenges. In the case of Tathony Holdings v James Street Hotel Limited the Plaintiff, the owner of an apartment block in central Dublin, sought orders restraining the Defendant’s planned development of a seven-storey aparthotel on an adjacent site on the grounds that it would interfere with the apartment block’s Right to Light. While the case ultimately settled, the mere fact that the defendant held a grant of planning permission for the development was not in itself sufficient to defeat the Right to Light claim.

Given that the planning process is designed to assess the overall impact of a development on its environs and the potential loss of amenity, developers (understandably) want issues of light to be determined as part of any planning application. As the planning process provides a well-trodden path for public consultation and third-party submissions, it seems logical that concerns regarding light should be aired as part of or in tandem with that process. County Development Plans, planning guidelines, third party observations and the planning appeals process itself should provide an adequate framework for detailed technical deliberation on whether a proposed development will diminish light in a way that causes nuisance to adjoining premises. Currently however a grant of planning permission is not determinative of whether Rights to Light have been adversely affected.


As part of its 2014 stakeholder consultation on Rights to Light, the Law Commission of England and Wales noted the “consistent message from developers … [is] … that they need to know, at some point, whether an injunction is seriously sought and to have a cut-off point after which it is no longer a possibility”. In the context of authorised development, surely this cut-off period should align with the conclusion of the planning process, which already provides a robust framework for stakeholder consultation and detailed technical assessment of a development’s impact on its surroundings. Creating this alignment would require legislative change; an immediate action that Government can take to deal with one of the many viability issues facing sustainable urban development.


[1] Project 2040 National Planning Framework

[2] Housing for All | A New Housing Plan for Ireland

[3] Dixon J. McGrath v Munster and Leinster Bank Limited [1959] I.R. 313 at 327 

[4] See Society of Chartered Surveyors Ireland Rights of Light – Guidance Note

Written by:

James Lawless


+353 (0)1 440 8337

Michelle McArdle


+353 (0)1 440 8313

Article from – TRENDS Real Estate No 9

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