Higher-Risk Buildings under the Building Safety Act

The regulations which will govern how Higher-Risk Buildings under the Building Safety Act 2022 are to be measured, as well as determine which categories of buildings will be exempted, were published in draft just before Christmas and included a few surprises. 

On 20 December 2022, the Department for Levelling Up, Housing & Communities published its long-awaited response to the earlier consultation on the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations, alongside laying the draft regulations before Parliament a day earlier. Assuming that the regulations will shortly be passed into law, here we explore a few of the nuances and a surprising new feature that emerged from the draft.

Will my building be caught by the new regime?

Although the Building Safety Act itself had already set out the key parameters for what constitutes a Higher-Risk Building (namely, buildings in England that are at least 18 metres in height or have at least seven storeys), the details were to be fleshed out in regulations – both for the purposes of establishing which new buildings would be subject to the more stringent requirements in their design and construction phase, as well as determining which buildings (new and existing) would be subject to the regime of ongoing building safety management once occupied. 

Understanding the precise definition of Higher-Risk Buildings and how their height and number of storeys are to be measured is therefore vital for developers and existing building owners who need to know whether or not they will be bound by the new building safety regime when it comes into force. Time is especially tight for owners of existing buildings, as they will only have six months from April 2023 to register their building with the Building Safety Regulator if it does fall within the definition of a Higher-Risk Building.

How do I measure a building's height?

As expected, the draft provisions setting out how to measure the height of a potential Higher-Risk Building are largely in line with the earlier consultation and indeed the rules that are already in the Building Safety Act governing "Relevant Buildings". These are existing buildings that are at least 11 metres in height or have at least five storeys and which are subject to the Building Safety Act's leaseholder protections regarding who pays for the cost of remedying historic defects.

Broadly, for Higher-Risk Buildings, height is to be measured from the lowest part of the surface of the ground adjacent to the building, up to the horizontal projection from the top of the floor surface of the top storey (ignoring any storey which consists exclusively of roof-top plant or machinery). When measuring the number of storeys, underground levels and gallery levels are also to be ignored.

However, there are a couple of nuanced differences compared to the regime for Relevant Buildings. For example, when measuring the height of a Relevant Building, intermediate storeys consisting of plant and machinery rooms can be ignored, whereas only roof-top plant and machinery can be ignored when measuring the height of Higher-Risk Buildings. Conversely, when measuring the number of storeys, all storeys containing plant and machinery are still counted for Relevant Buildings, whereas roof-top plant and machinery storeys are ignored for Higher-Risk Buildings. 

Mezzanine or gallery floors are also treated slightly differently. These can only be ignored in Higher-Risk Buildings if they are less than 50% of the internal floor area of the largest storey which vertically overlaps with the gallery floor, whereas mezzanine floors in Relevant Buildings can be excluded if they are less than half the size of the largest storey anywhere in a larger complex building. Who knew that counting the number of storeys in a building could be so complicated?

Where does a "building" start and end?

The biggest surprise in the draft regulations is the introduction of a new concept of "independent sections", which only applies to the in-occupation regime and not the design and construction phase. A building can now be a standalone structure not attached to any other structure, a set of two or more structures attached to each other, or an "independent section" within any such standalone structure or aggregate set of structures. 

Again, untangling what this means in reality will be crucial for building owners because each Higher-Risk Building (as defined by the regulations) will have to be separately registered with the Building Safety Regulator and have its own Accountable Person(s) and Principal Accountable Person who will be responsible for complying with the in-occupation obligations under the new regime.

The key point to note is that independent sections do not need to be vertically severable from the rest of the structure, nor be capable of independent redevelopment (another difference from the definition of a Relevant Building). They simply need to have a separate access or entry point, whilst not having access to any other residential section of the wider building. So even a residential core within a larger mixed-use scheme could be a separate Higher-Risk Building. Moreover, for the purposes of measuring the number of storeys, any above-ground storey that is beneath such an independent section would also be counted, even though it would not form part of the relevant section (e.g. ground floor commercial space or podium levels).

Finally, if you do have an independent section which is sufficiently tall to be a Higher-Risk Building, then this Higher-Risk Building will also include any plant room containing equipment for the provision of services to that independent section. Such plant rooms do not need to be physically contiguous with that section, and could potentially include off-site district heating plant. Whoever happens to own such plant rooms could then find that they become an Accountable Person for several Higher-Risk Buildings that are served by such plant.   

Which types of buildings are excluded?

Thankfully, the list of exemptions is far simpler than the definitions of buildings, and broadly follows what was expected from the consultation. Higher-Risk Buildings must contain at least two dwellings or other units of living accommodation to be caught within the design and construction phase (mirroring the equivalent requirement already in the Building Safety Act for the in-occupation phase). However, this does mean that predominantly commercial buildings could still be included if for example they contain living quarters for on-site staff, or a couple of penthouse apartments.

Secure residential institutions (e.g. prisons), military premises (e.g. military barracks) and hotels are all excluded, whilst hospitals and care homes are included within the design and construction phase but excluded from the in-occupation phase. 

Clarity as to whether serviced apartments are included or excluded would be welcome, as this was an issue raised by some respondents to the consultation. The draft regulations do not define what is a "hotel", and the Government has now moved away from the language of "temporary leisure establishment". 

The Government has promised that full guidance on all the detailed nuances in the regulations will be published once the secondary legislation has been approved by Parliament and before the new regime comes into force. It will be important for building owners whose buildings might fall within the definition of Higher-Risk Buildings to review the guidance and prepare their registration applications in a timely manner.

Buildings in Wales

The Building Safety Act 2022 (Commencement No. 2) (Wales) Regulations 2022 became law on 9 December and bring into force the provisions of the Building Safety Act which give the Welsh Ministers the power to issue their own regulations as to the definition of Higher-Risk Buildings in Wales, subject to a requirement to undertake a consultation beforehand. 


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