Understanding the daylight requirements in Derbyshire Dales is essential for anyone planning an extension, a new home or a larger residential scheme in this part of rural Derbyshire. The district stretches from Matlock and Wirksworth through Ashbourne and the towns of the Derwent Valley, and its planning decisions are guided by a clear set of adopted policies on design and residential amenity. This guide explains how the local planning authority approaches daylight and sunlight, which policies and national standards apply, and how to put together an application that stands up to scrutiny.
Who decides daylight requirements in Derbyshire Dales?
For most of the district, the local planning authority is Derbyshire Dales District Council rather than Derbyshire County Council. The county council deals with matters such as minerals, waste and education, but householder extensions, new dwellings and most residential development are determined by the district council.
One important local quirk is that a substantial part of the geographic Derbyshire Dales lies within the Peak District National Park, which is a wholly separate planning authority with its own development plan. Bakewell, for example, and many of the surrounding villages fall under the Peak District National Park Authority. If your site sits within the National Park boundary, the policies discussed here do not apply and you should refer to the National Park Authority instead. The district council determines applications for the areas outside the National Park, including Matlock, Matlock Bath, Wirksworth, Ashbourne, Darley Dale and the Derwent Valley settlements.
The adopted Local Plan and its amenity policies
The relevant development plan is the Derbyshire Dales Local Plan 2013-2033, which was formally adopted on 7 December 2017. It sets out the policies used to determine planning applications across the district outside the National Park. Two policies in particular govern how daylight, sunlight and overshadowing are weighed.
Policy PD1: Design and Place Making
Policy PD1 is the principal design policy. Among its requirements, it states that development must achieve a satisfactory relationship to adjacent development and must not cause unacceptable effects "by reason of visual intrusion, overlooking, shadowing, overbearing effect, noise, light pollution or other adverse impacts on local character and amenity." The explicit reference to shadowing and overbearing effect is what brings daylight and sunlight squarely into the planning balance. A scheme that would significantly overshadow a neighbour's garden, or block light to habitable room windows, can be refused under this policy even where it is otherwise well designed.
Policy HC10: Extensions to Dwellings
For the most common type of application, the householder extension, Policy HC10 is the key test. It supports extensions and incidental outbuildings provided, among other criteria, that the plot is large enough to accommodate the addition "without resulting in a cramped or overdeveloped site" and that the height, scale, form and design are in keeping with the original dwelling and its wider setting. Cumulative additions are taken into account. In practice, a bulky two-storey rear or side extension that looms over a neighbouring property or casts a heavy shadow can fall foul of both HC10 and PD1.
Together, PD1 and HC10 mean that the impact of a proposal on the daylight and sunlight enjoyed by neighbouring homes and gardens is a material consideration in Derbyshire Dales, even though the Local Plan does not set out numerical daylight targets of its own.
Is there a Derbyshire Dales daylight or design SPD?
This is where it pays to be accurate. Derbyshire Dales District Council has adopted a number of Supplementary Planning Documents, including a Landscape Character and Design SPD, a Climate Change SPD (adopted in 2022, which addresses building design, density and orientation), a Developer Contributions SPD (adopted February 2020), a Conversion of Farm Buildings SPD and a Shopfront and Commercial Properties SPD.
However, the council does not currently publish a dedicated daylight and sunlight SPD or a numerical residential extensions design guide that sets out specific daylight angles or distances. There is no council-specific daylight calculation method. Instead, the assessment of daylight and sunlight is carried out against the amenity tests in Policies PD1 and HC10, informed by national policy and recognised technical guidance.
In the absence of a local numerical standard, the established benchmark for assessing daylight and sunlight is the Building Research Establishment guide BRE BR 209, Site Layout Planning for Daylight and Sunlight: A Guide to Good Practice (2022 edition), alongside the British Standard BS EN 17037 on daylight in buildings. The National Planning Policy Framework (NPPF) reinforces this by requiring development to achieve a high standard of amenity for existing and future occupiers. These documents are applied through the amenity requirements of the adopted Local Plan, giving Derbyshire Dales case officers an objective framework against which to measure overshadowing, loss of daylight to windows, and sunlight to gardens and amenity space.
What a robust daylight assessment looks like
Where a proposal could affect a neighbour's light, a professional daylight and sunlight report provides the evidence an officer needs. A BR 209 (2022) assessment typically considers:
- Vertical Sky Component (VSC) at neighbouring windows, the standard measure of how much skylight reaches a window;
- Daylight distribution within affected rooms, sometimes assessed using the No Sky Line;
- Annual Probable Sunlight Hours (APSH) for windows facing within 90 degrees of due south;
- Overshadowing of gardens and amenity areas, using the BRE recommendation that at least half of an amenity space should receive some sunlight on 21 March.
Presenting these results clearly, and explaining where a scheme meets the BRE guidelines or where any shortfall is modest and justified, helps demonstrate compliance with Policies PD1 and HC10 and reduces the risk of refusal or a neighbour objection derailing the application.
Two local points worth remembering
- Conservation areas and heritage matter here. Matlock Bath, Wirksworth and the wider Derwent Valley Mills World Heritage Site corridor contain numerous conservation areas and listed buildings. Where daylight, design and heritage considerations overlap, a careful assessment that respects both amenity and historic character is especially important.
- Topography is a real factor. The Dales are steep and hilly, with terraced and stepped housing common in Matlock and the valley towns. Sloping sites change how shadows fall and how an extension is perceived, so a daylight assessment that takes account of levels is far more persuasive than a flat-site assumption.
How Fortress Associates can help
Fortress Associates provides our daylight and sunlight report service for homeowners, architects and developers across Derbyshire Dales and the rest of the UK. Our reports are prepared to BRE BR 209 (2022) and BS EN 17037 and are written to support your application under the adopted Local Plan. We work to a 4 to 5 working day turnaround and ask for no advance payment. We also prepare Building Regulations drawings to Approved Documents A to S. To discuss your scheme, please get in touch.
Sources & further reading
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