The Ministry of Housing, Communities and Local Government (MHCLG) has updated its guidance notes on the definition of a "higher-risk building" (HRB) during design and construction and during occupation to note that it is consulting with the Building Safety Regulator (BSR) on a proposal for legislative change to clarify the position in relation to roof gardens and HRBs.

The updated guidance also clarifies MHCLG's view that roof gardens should not be considered storeys when determining whether a building is a HRB.

In this article, we explore recent developments as to whether roof gardens count as storeys when assessing if a building is a higher-risk building, why this matters for developers and owners and how upcoming regulatory changes may affect compliance.

How is a "higher-risk building" defined?

The definition of a HRB is set out in the Building Safety Act 2022 (BSA), as supplemented by The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 (the 2023 Regulations).

During the design and construction phase, these define a HRB as a building that is at least 18 metres in height or has at least seven storeys and:

  • Contains at least two residential units;
  • Is a care home; or
  • Is a hospital.

During the occupation phase, they define a HRB as a building that is at least 18 metres in height or has at least seven storeys and contains at least two residential units.

While care homes and hospitals are included in the design and construction phase of the new regime, they are excluded from the in-occupation phase (as are secure residential institutions, hotels and military accommodation).

On the basis of the above, it might sound simple to identify whether your building is a HRB – but in practice, this can be complex.

What about roof gardens?

The 2023 Regulations do not define what is meant by a "storey". However, Regulation 6 does list certain items which will not constitute a storey, including “any storey which is a roof-top machinery or roof-top plant area or consists exclusively of roof-top machinery or roof-top plant rooms”.

The 2023 Regulations are silent on how rooftop gardens should be treated.

However, the Government guidance notes referred to above offer further guidance on what does and does not constitute a storey, indicating that:

"A storey must be fully enclosed to be considered a storey. The roof of a proposed building should not be counted as a separate storey. Open rooftops such as rooftop gardens are not considered storeys and should not be counted as such when determining the number of storeys or measuring the height."

This goes beyond the content of the 2023 Regulations, which are silent on whether or not a storey would need to be "enclosed" to be counted as a storey for these purposes.

Why has MHCLG updated its guidance?

In July 2024, in Smoke House & Curing House, 18 Remus Road, London E3 2NF: LON/00BG/HYI/2023/0024 - GOV.UK, the First-tier Tribunal (FTT) opined that a roof garden should be classified as a storey when determining whether a building meets the height and storey criteria under the 2023 Regulations.

In reaching this view, which was contrary to the Government guidance, it expressed doubts over the status of Government guidance, opining that it does not "constitute a reliable interpretation of law".

This led to industry and sector confusion about the status of Government guidance and prompted MHCLG to issue a statement and to update its guidance notes in October 2024, indicating that it was considering the views expressed by the FTT.

In its May 2025 update, MHLCG has confirmed that it has "carefully considered" the FTT's view and recognises the need to provide clarity within the legislation. As such, it is consulting with the BSR to amend the 2023 Regulations to make it clear that roof gardens should not be considered a storey.

In the meantime, MHCLG advises the sector and regulatory bodies to continue to refer to current Government guidance on this issue.

Smoke House criticised on appeal

It is worth noting that the Upper Tribunal also handed down its decision in the Smoke House appeal in May 2025. The FTT decision was subject to criticism in that appeal, to the point that the FTT's decision has been partially set aside on grounds of serious procedural irregularity and a breach of natural justice.

In particular, the Upper Tribunal commented that the FTT had no authority to decide whether the building was or was not a HRB. It observed that the FTT's "public expression of its opinion in its decision, including its comments on government guidance, has doubtless caused concern and confusion for building safety professionals. All of this illustrates how dangerous it is for a tribunal to express a view about a matter that is not within its jurisdiction."

Key actions

It is clear from the most recent update to the Government guidance notes that MHCLG does not consider rooftop gardens to be a storey for the purpose of assessing whether a building is a HRB. The 2023 Regulations are expected to be amended to align with this view.

We will, of course, need to wait for the Regulations to be updated so that we can see the detail of the same but in the meantime, it is worth:

  • considering whether this might impact your analysis of your portfolio/properties you are buying;
  • keeping clear records of when and how measurements of buildings close to the HRB height thresholds were assessed;
  • being mindful of the scope of any contractual commitments you enter into in relation to HRBs – this remains a reminder that building safety is an evolving area and, whilst Government guidance is a useful aide, if it is not consistent with the BSA or the various regulations that have been brought into force in order to implement the BSA, it is the BSA and those regulations that you should primarily be led by; and
  • reaching out to us if you need help in ascertaining and applying the applicable law.

If you have any queries on this article, please get in touch with Gemma Whittaker, Danielle Klepping or Sean Garbutt.