Planning matters blog | Lichfields

Planning matters

Our award winning blog gives a fresh perspective on the latest trends in planning and development.

The changes to study of daylight and sunlight brought about by the revised BRE Report (BR209) have highlighted the requirement for a holistic approach to building design and the planning process. The necessity for interaction between natural light studies, overheating studies, landscape design and sustainability studies has become apparent as the need to balance natural light amenity against the needs of Building Regulation compliance is brought into the design process.
As always, it is in urban environments that the balancing act becomes most difficult. Whilst the revised British Standards (BS(EN) 17037) and the BRE Report provide reduced targets via the UK Annex for ‘difficult to light properties’, there are still difficulties achieving full compliance within modern developments in a built-up area. These difficulties, predominantly driven by the proximity of neighbouring and proposed buildings and the prerequisite to provide private amenity spaces, typically taking the form of balconies above the main windows of the units below, are further compounded by overheating concerns.
It is often the case that rooms at the lowest levels of developments have non-openable windows for acoustic and/or security reasons. This leads to ventilation issues that in turn lead to overheating issues, as such, it is often necessary to reduce glazed areas to help counter the effects of heat gain in these rooms. These reductions in window sizes obviously lead to further daylight access issues. There is clearly a need to discuss these restrictions as part of the planning process to allow Planning Officers and Committee members to appreciate the balance required and draw pragmatic conclusions.
It is becoming apparent that the role of daylight and sunlight consultants and their reports needs to expand beyond simply undertaking technical analyses to informing the design process in conjunction with other technical specialists. There is a necessity for daylight and sunlight consultants to interact with other consultants within the design team. As natural light tests are often the first detailed assessments done on a new project, daylight and sunlight consultants increasingly need to lead discussions on where natural light access can be restricted and where there are potential issues that will need alternative mitigation methods to combat overheating and other concerns.
The new daylight tests, if applied correctly, provide a wealth of information regarding the ingress of natural light within a room. The tests allow the exploration of window design, room layout, balcony arrangements, internal facades, external facades and landscaping. With the Spatial Daylight Autonomy test, room orientation becomes another element that greatly impacts the results but again can lead to other issues.
The worked example shown below explores the impacts detailed internal and external material design can have on daylight conditions within a room. The room assessed remains of the same layout and dimensions, but the specification of lighter colours both internally and externally is altered under each option. These seemingly modest changes in material specification can significantly impact daylight penetration within a room.
The BRE Report discusses surface reflectance and provides that they should represent real conditions. The guidance goes further and states that “Where surface finishes have been specified or measured on site, they can be used in the calculations…”.
Intelligent use of daylight calculation methods and clear reporting can show that even where rooms do not meet the BRE Report/BS (EN) guidance, daylight and sunlight levels may still be considered appropriate in the sense implied by the NPPF and NPPG.
Lichfields’ Neighbourly Matters team has been using the revised daylight and sunlight calculations in our design advice since the changes to the British Standards. We are championing a front-loaded approach to daylight and sunlight analysis and closer interaction between relevant consultants on all of our major development projects.
For further information please contact Toby Rogan-Lyons.


Do Not Pass Go! How to start on site with BNG

Do Not Pass Go! How to start on site with BNG

Heather Overhead 26 May 2023
There’s been a flurry of recent activity from the Government in relation to the forthcoming mandatory Biodiversity Net Gain (BNG) requirement in England. In February they released their long-awaited response to the consultation on regulations and implementation, alongside some new guidance. In March, Natural England published the Biodiversity Metric 4.0 which includes a small sites metric.
One thing that is clear is Government still intends for the mandatory requirement to come into force for all major applications submitted in England this November, although secondary legislation is required to enact this.

What do we know?

The guidance and consultation response have provided clarity on some of the outstanding issues and has filled in some of the detail that was missing.
Key things we now know are:
  • Timescales: applications submitted from November this year for major development (in England) will be subject to the mandatory BNG condition, for ‘small sites’ (i.e. non-major development) this will be imposed on applications submitted from April 2024 and for NSIPs ‘no later than April 2025’;

  • Exemptions: development impacting habitats below a set threshold, householder applications and BNG sites will be exempt, whilst previously developed land, Change of Use and temporary won’t be exempt;

  • Section 73 applications: These will only be subject to the mandatory BNG requirement where the original permission was granted after BNG became a mandatory requirement;

  • Outline and phased permissions: the approach to delivery of BNG from the whole development on a phase-by-phase will be required up front but LPAs will have some discretion how and when delivery is achieved. There will be a requirement for approval of a biodiversity gain plan prior to commencement of each phase;

  • Mechanics: Biodiversity gains will be secured through a combination of planning conditions, planning obligations or conservation covenants and enforced primarily by the planning enforcement regime;

  • Biodiversity units: it is anticipated that a biodiversity unit market will develop, whereby any landowners will be able to sell biodiversity units (subject to meeting the relevant requirements) - see Government guidance for more information. If a development delivers a BNG of more than 10%, the excess units can be sold on the market;

  • Biodiversity Gain Site Register: this will be operated by Natural England and will record all off-site gains. Registration of off-site units will be mandatory, and will require a binding legal agreement with Habitat Management and Monitoring Plan (HMMP) to qualify. We are yet to see the register, however it is expected to be up and running by November;

  • Government credits: these will be sold by Natural England, the price will be set intentionally high to discourage their use, and they will be phased out once the biodiversity unit market has matured. The initial price will be published in May 2023;

  • Stacking: you can sell biodiversity units and nutrient credits from the same parcel of land relying on the same enhancements, however there are restriction on combining sale of biodiversity unit with other land management schemes. See guidance for info.


What don’t we know?

Whilst the recent guidance and response to the consultation is helpful and provides some much needed clarity, there is still a way to go to get the system up and running smoothly by November. In the consultation response there is acknowledgement that secondary legislation and further guidance is required in relation to a range of topics, and that the Government are working to resolve some issues raised. The key outstanding items are:

  • Biodiversity information: A Biodiversity Gain Statement must be submitted with the planning application, and a Biodiversity Gain Plan must be approved to discharge the BNG condition, however, we still haven’t seen templates for these documents. We are also still waiting on a HMMP template (which will be required for registration of off-site gains);

  • Outline and phased permissions: Secondary legislation and guidance is required to clarify and formalise processes for applying the BNG requirement;

  • Off-Site Gains: further guidance is required to clarify what constitutes “appropriate off-site biodiversity gains for a particular development”. The price of registering off-site gains is yet to be determined – a range of £100 to £1,000 is given. Secondary legislation is required in relation to processes for making and determining applications to the register;

  • On-Site Gains: there are uncertainties around timescales for provision and what threshold would trigger a requirement for a formal mechanism to secure gains

  • Exemptions: Secondary legislation is required to implement exemptions, including for impacts on ‘irreplaceable habitats’. Further consideration is being given to how to exempt ‘small scale self build plots’, whilst avoiding unintended consequences;

  • The long term: biodiversity gains must be maintained for at least 30 years, but what happens after that? The consultation response is clear that the intention is for the vast majority of gain sites to remain in some sort of “conservation management”, and suggests that landowners should take this into account. The mechanics of how this may be controlled are yet to be determined.

Will the new system work?

BNG is already being applied across large parts of the country at varying percentages so we know that a system can work. But will the system due to come into force on permissions for major development submitted from England in November work or is it over-designed and overly prescriptive? The key to its smooth running will be an early launch of the Biodiversity Gain Site Register, which is specified in the Environment Act as being necessary for the use of off-site biodiversity gains.
Get it touch if you’d like to discuss how to navigate your way through the BNG system