If you are planning an extension, a new dwelling or a larger residential scheme in Bishop's Stortford, Hertford, Ware, Sawbridgeworth or Buntingford, understanding the daylight requirements in East Hertfordshire is an important early step. East Herts District Council is the local planning authority (LPA) that determines planning applications across the district; Hertfordshire County Council is not the LPA for these decisions. This guide sets out the local policy framework, the council's specific daylight and sunlight validation requirement, and how a professional assessment can support a successful application.
The planning framework: daylight requirements in East Hertfordshire
The statutory development plan for the district is the East Herts District Plan 2018, which was adopted in September 2018. It contains the policies the council uses to assess planning applications, including protection of the living conditions of existing and future occupiers.
The key policy for daylight and sunlight is:
- Policy DES4 (Design of Development) requires development to be designed to a high standard and not to be significantly detrimental to the amenity of neighbouring occupiers. The policy expressly addresses matters such as loss of sunlight and daylight, overbearing impact, overlooking and loss of privacy. Where a proposal would harm the light reaching a neighbour's windows or garden, it can be refused under DES4.
DES4 works alongside the wider design and place-making policies of the District Plan and the National Planning Policy Framework (NPPF), which requires development to provide a high standard of amenity for existing and future users.
The council's daylight and sunlight validation requirement
East Herts is one of the districts that sets out an explicit local requirement for daylight and sunlight evidence. The Joint Validation Checklist (Hertfordshire County Council and East Herts District Council) lists item L9 - Daylight and Sunlight Assessment. It is required:
"Where there is a potential adverse impact upon the current levels of daylight/sunlight enjoyed by adjoining properties or building(s), including associated gardens or amenity space."
The checklist points applicants to the BRE guidance "Site layout planning for daylight and sunlight: a guide to good practice", used in conjunction with the British Standard BS EN 17037 (Daylight in Buildings), and references NPPF paragraphs 185, 186, 210 and 211. This means that for many applications in East Herts, a daylight and sunlight report is not optional - it is a validation requirement before the application can be registered.
How daylight and sunlight are technically assessed
The recognised technical benchmark is the Building Research Establishment guidance, now in its current form as BRE BR 209: Site Layout Planning for Daylight and Sunlight - A Guide to Good Practice (2022 edition), read together with BS EN 17037. A typical assessment for an East Herts application considers:
- Vertical Sky Component (VSC) - the skylight reaching a neighbouring window, with 27% the usual target.
- Daylight Distribution (no-sky line) - how far daylight penetrates into existing rooms.
- Annual Probable Sunlight Hours (APSH) - for windows facing within 90 degrees of due south.
- Overshadowing of gardens and amenity space - testing whether at least half of an amenity area receives sunlight on 21 March.
The 45-degree and 25-degree first checks for extensions also feed into this work. A report measuring these factors gives officers the evidence they need to apply Policy DES4 and to validate the application under requirement L9.
Local context: development pressures in East Hertfordshire
Daylight and sunlight issues arise across the district in distinctive settings:
- The Gilston Area and Harlow garden communities - the District Plan and the Gilston Area Charter SPD (2020) support major new neighbourhoods on the southern edge of the district, near Harlow, where new higher-density development requires careful daylight planning for both new and existing homes.
- Bishop's Stortford and Old River Lane - the Old River Lane SPD (2022) guides regeneration in the town centre, where taller mixed-use buildings make daylight, sunlight and overshadowing key design considerations.
- Historic towns of Hertford and Ware - these have tight, characterful streets and many listed buildings, so extensions and infill plots frequently raise close-proximity light and privacy concerns under DES4.
Because East Herts combines large strategic growth with sensitive historic centres, a robust daylight and sunlight assessment is often essential to securing consent.
When you may need a daylight and sunlight report
You should commission a report where your proposal could reduce the daylight or sunlight reaching a neighbour - for example a two-storey or rear extension near a boundary, a backland or infill dwelling, a flatted scheme, or any case where the council flags requirement L9 at validation. The report demonstrates compliance with Policy DES4 and satisfies the council's validation list.
How Fortress Associates can help
Fortress Associates provides our daylight and sunlight report service for projects throughout East Hertfordshire and across the UK. Our reports are prepared to BRE BR 209 (2022) and BS EN 17037, satisfying the council's L9 validation requirement and supporting compliance with Policy DES4. We work to a 4-5 working day turnaround with no advance payment. See our services or contact us to discuss your scheme.
Sources & further reading
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