Building Regulations Transitional Period: Why 14th June 2022 is a key date for developers

From 14 June 2022 there will be a raft of changes to the Building Regulations, which, potentially, will have a significant impact upon the cost of building new homes for developers. Consultations on these measures have suggested the direct cost increase at between £6,000 and £10,000 depending on the design, the size of the property and its specification.

There is however an excellent opportunity for property developers to avoid some of these costs – but only if they act quickly.



The latest changes to Approved Documents L (conservation of fuel and power) and F (ventilation) for new and existing buildings, and a new Approved Document O (Overheating) for new residential buildings are an interim measure with a view to progressing to the Future Homes and Future Building Standards 2025, which are a set of standards that will complement the Building Regulations to ensure new homes built from 2025 will produce 75-80% less carbon emissions than homes delivered under current regulations.

The changes coming into force therefore represent a meaningful uplift in building performance requirements and are perhaps the most impactful changes in a generation.

What are the key changes for developers?

Part L – conservation for fuel and power

  • U values which are a measure of thermal performance of a material will improve across the board, requiring additional insulation to be used.
  • On site audits of thermal bridging will be required. Drawings (similar to but in more situations to the current “Accredited details”) are to be provided within the Building Regulation application package and photographic evidence will be required to demonstrate that the correct execution of these typical approved details  (12 photographs minimum, referenced with location/ plot number, date and time). EPCs will not be issued without these.
  • All secondary pipe work for hot water, i.e. to taps is required to be insulated.
  • Highly glazed extensions will become harder to achieve a pass (although it can be said that this item is perhaps the most onerous point to consider when looking at extensions as the effect of the new Building Regulations mostly have a focus on ‘new-build’ situations).
  • If using a mains gas boiler photovoltaic solar panels will be required
  • 100mm cavities will effectively be non-compliant and wall constructions will require additional internal insulation
  • Oil boilers will become virtually impossible to achieve a pass
  • Triple glazing is likely to become the norm
  • These changes are likely to require the engagement with an energy assessor pre-planning. Some Council’s also have adopted energy targets (normally contained within Planning conditions) which are well in excess of even the new Building Regulation requirements which will require some very careful thermal design and balancing to achieve compliance.

Part F – Ventilation

  • Buildings which achieve an air tightness score of 3 or less and are considered highly airtight will require a continuously running mechanical extract system such as mechanical ventilation with heat recovery and continuous mechanical extract ventilation instead of natural ventilation.
  •  “Natural” ventilation will no longer be suitable for many new build dwellings.

Part O – Overheating

  • Aims to avoid excessive solar gain in well insulated properties and is based upon geographic location
  • Provides for simplified compliance where with a maximum percentage of floor area for glazing is permitted, taking into account cross ventilation.
  • In other instances a more expensive “dynamic thermal analysis” of buildings is required to achieve compliance, i.e. take into account external factors such as shading from trees.

What can developers do to avoid these costs?

The “Transitional Provisions” come into force 15th June 2022, that is to say projects where a building regulations application has been made before this date will benefit from the old regulations, provided a “start on site” for that particular building is made before 14th June 2023.

The application itself can be made at low cost with no details or plans required at this stage. In fact, no planning permission is required and the applicant does not even need to have purchased the site.

It would therefore be wise for any developer who has yet to commence a build, perhaps yet to apply for planning, or who is perhaps in early negotiations to purchase to make a speculative Building Regulation application prior to 15th June 2022 to avoid the potential for their Consultants to have to prepare much more information to demonstrate compliance and the potential extra construction costs.

Currently Building Control providers such as Local Authorities or Approved Inspectors are seeing a huge upturn in requests fee quotations and, subsequently, application numbers where people are seeking to take advantage of a validated submission before the “cut-off” date.

The second stage of the requirement of the transitional provisions is a requirement to commence “substantial” work on site prior to 15th June 2023. This does not necessarily mean a full commencement of construction, the following steps will satisfy the requirements:

  • Excavation of trenches for footings
  • Digging out and preparation for raft foundations
  • Piling
  • Drainage work specific to the buildings concerned

These will need to be on a plot for plot basis not one single plot “start” on a larger site

Sufficient plans are required by this stage for each plot to ascertain which plot the works relates to.

Paul Munnings in the commercial property team at Prettys specialises in advising housebuilders in relation to all aspects of the acquisition, planning, construction and disposal process, offering highly pragmatic and commercial advice based on his own experiences as a developer.


Paul Munnings