overshadowing assessment
AKT Surveyors deliver BRE 209-compliant Overshadowing Assessments for gardens, courtyards, terraces and public realm - clear diagrams, quantified results, and proportionate design tweaks that keep projects on track.
What is an Over Shadowing Assessment
Using BRE 209 guidance (sunlight to open space), we test the proportion of amenity area receiving ≥2 hours of sun on 21 March, before and after your proposal. We then visualise hourly shadows, explain % compliance, and recommend targeted mitigations (set-backs, local height trims, introducing gaps, chamfers) to unlock approval.
2-4 Ringers Road, Bromley
Wadworth Brewery, New Park Street
360, 17 Marlborough Street, Bristol
At-a-glance: Daylight & Sunlight Scopes
| Topic | Sunlight to Open Space (BRE 209) | Shadow Diagrams / Visuals | Mitigation Levers | Typical Outputs |
|---|---|---|---|---|
| Metric | % of amenity area with ≥2 hours sun on 21 March (pre/post). | Hourly shadows (9–18h) on 21 March; seasonal panels if requested. | Local height trims, set-backs, step-backs, chamfers, introduce gaps, orientation tweaks. | Compliance tables, before/after graphics, annotated plans. |
| Purpose | Protect reasonable sun access to gardens/courtyards & public realm. | Communicate impact clearly to officers, neighbours and committees. | Focus change where it unlocks the biggest % gain for least mass loss. | Officer-friendly narrative with policy references. |
| Typical Triggers | Tall/long forms near private gardens or shared courtyards. | Sensitive sites, heritage areas, contested neighbour interfaces. | Re-mass locally, soften corners, pull back upper storeys. | Compliance summary, risk heat maps, mitigation log. |
| Coordination | Align with plot layouts and landscape design. | Integrate with Design & Access visuals. | Balance with VSC/NSL/APSH and Right to Light where relevant. | Final PDF report + appendices for validation. |
Why it matters
- Officer-friendly evidence: crisp diagrams and tables aligned to policy.
- Design certainty: change only what moves the metric.
- Neighbour relations: transparent visuals that de-escalate objections.
- Speed: scoped to your LPA; fast addendums for late tweaks.
- Joined-up approach: consistent narrative with BRE windows and RoL.
Faq
Got questions about right to light in London?
Below are answers to the most common right to light questions we receive from London homeowners, architects and developers covering law, process, fees and what to send us.
No. Overshadowing tests sunlight to open space. Daylight/sunlight to windows uses VSC/NSL/APSH. Many schemes need both.
The proportion of amenity area achieving ≥2 hours of sun on 21 March, compared pre- and post-development.
Yes. We align overshadowing with VSC/NSL/APSH and, where relevant, Right to Light so narratives don’t conflict.
Existing/proposed plans, sections, elevations, storey heights, roof forms/dormers; DWG helps, scaled PDFs are acceptable.
Standard assessments 1–2 weeks; addendums 2–5 working days, scope-dependent.