The obvious choices when it comes to extensions

For many homeowners in need of extra space, an extension to the side of the house, a first floor extension over the garage and/or changing a hipped roof to a gable to accommodate loft conversion rooms are the obvious options. For a room over the garage or changing a hipped roof to a gable, there is no loss of external garden space making this a very common option for many homeowners.  

It seems that there is no negative to the homeowner…but beware of rights of light!

But I have planning permission for my extension? Should I still consider rights to light?

Converting a hipped roof to a gable may be undertaken as Permitted Development, without even needing to apply for planning permission. This means there is no opportunity for the possible consideration of loss of daylight and sunlight to a neighbouring house within the context of a planning application.

Whereas a two storey side extension or an extension over the garage would need planning permission and so, presents the opportunity for the planning officer to give due consideration to loss of daylight and sunlight to a neighbour.  However, it must be kept in mind that the BRE Daylight and Sunlight guide, adopted for use by most Local Authorities to assess loss of daylight and sunlight to neighbours, excludes any consideration of windows to non-habitable rooms.  And, of course, the windows at the side elevation of a neighbouring house are most likely to be to a stairwell, bathroom or utility, all non-habitable rooms and so excluded from consideration as part of the planning application, but still relevant with regards to legal rights of light!

Legal right of light risks of the side extension

Generally, if a window opening in a wall has been receiving natural light through it to the interior of the building for at least 20 years, that window opening will have obtained a legal right of light via Prescription; this is irrespective of the use of the room. Although the likelihood of an injunction would be likely to be affected by the room characteristics and use, in terms of the legal principle of being able to obtain a right of light, the room use makes no difference at all. This is one very significant way in which the consideration of the loss of daylight and sunlight as part of the planning process varies from legal rights of light, and this is very often relevant in relation to side extensions. 

Additionally, however, it must be noted that the consideration of natural light to neighbours within the planning system is simply different from a legal right of light assessment. The assessments and the critical thresholds (for pass/fail or an injury) are not the same. As a consequence, although it is quite often the case that, if a window passes the target figures within the planning system consideration of natural light to a neighbour, it will also not cause a legal right of light injury, that is not always the case. Therefore, even if the neighbour’s affected windows are to habitable rooms, and even if they have been assessed within the planning application, it cannot be taken for certain that there will not be legal right of light injuries. 

Furthermore, just to compound the risks, generally the side-to-side separation between neighbours is much smaller than the separation between front and rear elevations of houses which means that the impact of a side extension upon the light receivable at the neighbour’s side elevation windows is greater. Added to this is that often the affected ‘room’ will be a stairwell. Staircases, halls and landings tend to be strange shapes and often they are already quite dark which all make stairwells probably the most likely ‘room’ to suffer a legal injury.

Don’t fall into the side extension right of light trap

The pitfalls of side extensions effects on right to light are very easy to fall into…

It is often the case that rights to light are overlooked when it comes to side extensions. Examples of situations where this happens frequently would be; 

  • if your extension doesn’t require planning permission, 
  • if your extension has been granted planning permission including due consideration of loss of light to neighbours; 
  • or if you have hired an architect involved and they hadn’t raised this as an issue when they should have. 

You would not be alone in falling into this trap – on a domestic scale, this is the most frequent situation where we are approached by a neighbour concerned about loss of light from a domestic extension, and very often the person extending their home is completely unaware of the problem and genuinely shocked and surprised that they can have found themselves in this situation, with a half complete extension and a lawyers letter through their letterbox asserting a rights of light injury.

Might your proposed side extension cause a right of light injury to your neighbour

The answer is that legal rights of light must be considered separately from the planning side of things and that this is particularly so for a side extension for all of the reasons explained above.  

Especially for a hip-to-gable alteration, two storey side extension or for a room over the garage extension, the default position must be to assume a high risk of a legal right of light injury to the neighbour if they have side elevation windows.  It will not always be the case but there is generally a fairly high likelihood that your proposed extension might cause a legal injury to your neighbour.

Right to light injuries even when no planning permission is required

Don’t assume that you are fine because you didn’t need planning permission, you have obtained planning permission and/or that your architect didn’t flag this up to you as a risk.  


At Smith Marston, we are happy to have an initial discussion with you to give some general guidance on your specific situation and the potential risks associated with that. We can carry out a right to light assessment and will give you honest feedback and then, if appropriate, we can give you fee quote options as to how we might be able to assist you further.


Related Articles

Extraordinary Rights Of Light…Such As A Greenhouse

What About My Shed…Can That Have A Right To Light?

Is There A Legal Right To Sunlight To Windows Or My Garden?

Right to Light & Dormer Windows

45 Degree And 25 Degree Lines Rules Of Thumb

Section 203 of Housing and Planning Act 2016

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