If a planning officer has asked for a daylight and sunlight assessment, your next job is choosing the right consultant to produce it. The report can make or break a consent, so it pays to know what a good one looks like. This guide sets out what a top daylight and sunlight consultant in the UK should offer, the questions to ask before you hire, and how to choose in 2026.
What does a daylight and sunlight consultant do?
A daylight and sunlight consultant assesses two things: whether your proposed rooms receive adequate natural light (the internal assessment), and whether your scheme takes too much light from neighbouring homes through loss of skylight or overshadowing (the external assessment). Both are judged against the Building Research Establishment guide BR 209 (2022) and the British Standard BS EN 17037, using metrics such as VSC, NSL and APSH — which we unpack in VSC, NSL and APSH explained. The output is a report your local planning authority can rely on.
What to look for in a top daylight consultant
Not all reports are equal. A strong daylight and sunlight consultant should tick every one of these:
- Current-standard compliance. The report must be built on BR 209 (2022) and BS EN 17037, not the withdrawn 2011 guidance. Planning officers expect the current methodology.
- The right scope. A good consultant scopes the work correctly first time — internal daylight, external impact on neighbours, sunlight and overshadowing — so nothing is missed and you are not upsold later.
- Relevant experience. Look for experience with schemes like yours, whether a rear extension, a loft, an apartment block or a dense urban site. Local knowledge of how your authority interprets BRE targets is a real advantage.
- Early engagement. The best consultants test your massing early, before the drawings are frozen, so daylight shapes the design rather than forcing costly redesigns. Our first-time pass guide explains why this matters.
- Clear turnaround. Ask how long the report takes. A straightforward scheme should not take weeks longer than necessary.
- Transparent terms. You should know the scope, the fee basis and the timescale up front, with no advance-payment surprises. For a sense of the market, see our guide to daylight report costs in the UK.
- Plain-English reporting. A good report explains its findings clearly for the planning officer and for you — not just a wall of numbers.
Questions to ask before you hire
- Which standards will you assess against — BR 209 (2022) and BS EN 17037?
- Will you assess both internal daylight and the impact on my neighbours?
- Can you review my design early to flag risks before I submit?
- What is the turnaround, and what exactly is included in the fee?
- Have you worked on schemes like mine and with my local authority?
When you need a specialist versus a standard report
For most householder extensions, loft conversions and small residential schemes, a clear, standards-compliant report is exactly what the planning authority wants. For large, contested or previously-refused schemes in dense urban areas — where overshadowing and loss of light are hotly argued — you may want a specialist who can also support an appeal. Knowing which situation you are in helps you choose proportionately and avoid overpaying.
Warning signs of a weak daylight report
A few red flags should make you pause before instructing. Be wary of any consultant who still assesses against the withdrawn 2011 BRE guidance rather than BR 209 (2022); who quotes without asking basic questions about your site, neighbours and drawings; who cannot say whether they will assess internal daylight as well as the impact on neighbours; or who promises “guaranteed approval” — no honest consultant can guarantee a planning outcome. Vague scope is the commonest cause of disputes: two quotes can differ wildly simply because one covers a quick neighbour screening and the other a full internal-and-external study. Get the scope in writing. A good report should also be legible to a non-specialist — if the sample you are shown is an impenetrable wall of figures, the planning officer will struggle with it too.
How Fortress Associates can help
Fortress Associates prepares daylight and sunlight reports to BRE BR 209 (2022) and BS EN 17037 for homeowners, architects and developers across the UK. We can review your massing early to flag risks before the design is fixed, then produce the full report for submission — typically within four to five working days, with no advance payment. Browse our services or get in touch to talk through your scheme. New to the process? Start with what is a daylight report.
Sources & further reading
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