Last edited 17 Oct 2024

Roof terraces and higher-risk buildings

1 Introduction and context of higher-risks
2 Interpretation of the guidance and relationship to legislation
3 The Smoke House & Curing House Tribunal
4 Building Safety related Orders
5 Guidance criteria for higher risk buildings
6 The Building Safety Act 2022, on higher risk buildings
7 The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023
8 Related articles on Designing Buildings
9 External links

[edit] Introduction and context of higher-risks

In the wake of the Grenfell Tower fire in 2017 the subsequent reviews and Public Inquiry, all those involved with construction need to ensure such a tragedy can never happen again. The Building Safety Act and related legislation created an entirely new building safety regime that impacts everyone involved in the planning, commissioning, design, construction, surveying, maintenance and management of all buildings and the built environment. The nature, definition, management and remediation of higher-risk buildings has been a key element of this building safety regime.

The Grenfell phase 2 final report, the final element of the Grenfell inquiry, indeed held some criticism of the definition of “higher-risk building” ( or HRB) as used in the Building Safety Act, for being primarily based on height alone. A building at least 18 metres in height, or importantly here, has at least seven storeys, and contains at least two residential units being deemed as higher risk. The report stated however, that, 'defining a building as “higher- risk” by reference only to its height is unsatisfactory and arbitrary in nature. More relevant is the nature of use, in particular, the presence of vulnerable people, for whom evacuation in an emergency presents difficulty. It is therefore recommended that the definition of a higher-risk building for the purposes of the Building Safety Act be reviewed urgently'. (113.7)

The complexity of the specific relationship between use of the roof space and the bearing it has on categorising a building as higher risk was highlighted by a first-tier tribunal, property chamber case regarding the property Smoke House & Curing House. The report of that tribunal asked: "Is the building in the higher risk category?" and in turn answered by saying: "59. Unfortunately, this is not a straightforward question even after a consideration of the relevant law and guidance."

[edit] Interpretation of the guidance and relationship to legislation

The first-tier tribunal, property chamber case regarding the property Smoke House & Curing House furthermore highlighted perhaps other issues that were indeed also highlighted by the final Grenfell Inquiry report, that is the nature of guidance documents themselves, how they are used and interpreted by professionals.

The final Grenfell Inquiry report described that the legal requirements of regulations in terms of functional requirements were not in themselve unsatisfactory, but the way statutory guidance in Approved Document B was expressed was deemed unsatisfactory in a number of respects. Chapter 6; the retention of Class 0, as a standard governing the fire performance of external wall panels, Chapter 48; consequences of expressing in an apparently prescriptive form what is actually guidance. As such the comments implied that Approved Document B does not provide the information needed to design fire safe buildings (113.10).

Investigations showed levels of competence were generally low at the time of the fire and many contractors, designers and building control officers treated statutory guidance as a definitive statement of the legal requirements. It is understandable that those who turn to the guidance for advice about how to comply with the Building Regulations are tempted to treat it as if it were definitive, but that is a danger that the Secretary of State needs to recognise and guard against. The inquiry recommended a revised version of the guidance that contains a clear warning in each section that the legal requirements are contained in the Building Regulations and that compliance with the guidance will not necessarily result in compliance with them. (113.12)

This article details of some of the references available regarding higher-risk buildings and the issue of roof terraces. In the same way as described above, although the guidance shown seems to imply a certain acceptable approach, the tribunal in referring to wider documents and to the specific set of circumstances of that buildings, saw this differently. It is an example of the point that guidance is not a definitive statement of requirements, and as such not an assured route to meeting the law. Some of the documents referenced are guidance, some legislative, and some regulatory, many were mentioned in the tribunal case, which concerned an application for a remediation order under section 123 of the Building Safety Act 2022, put forward leaseholders. The tribunal highlights a somewhat significant development in the understanding of "use" when it comes to roof spaces, and the practical reference to, and application of documentation surrounding the definition, remediation and management of higher risk buildings.

Whilst the tribunal case itself reported on its findings and made its decision based on these, there is the possibiity for the respondents to appeal the decison. Appeals to First-Tier Tribunals must first apply for permission to do so, and in the first instance to the First-Tier Tribunal. Generally this must be done within one month of the date of the Tribunal’s decision notice or statement of reasons and late appeals may not be accepted. Guidance indicates that this can only be done on the grounds that the Tribunal made an ‘error of law’. Examples of Errors of law are given as potentially including:

The First-Tier Tribunal applied the law incorrectly.
The Tribunal did not follow proper procedure.
The Tribunal did not make adequate findings of fact or give adequate reasons for its decision.
The Tribunal took irrelevant matters into account when making its decision.

[edit] The Smoke House & Curing House Tribunal

A full copy of the tribunal case LON/00BG/HYI/2023/0024 can be found in the following link, but below is a brief summary followed by terms, and documents relevant to and referenced by the case.

The case concerned an application for a remediation order under section 123 of the Building Safety Act 2022 for the remediation of elements of the building (identified in the original application as cladding to the internal courtyard) which represented a fire safety risk and to obtain disclosure and information regarding the fire safety assessment that was carried out on the building carried. The leasholer applicants citing that flats (which are owned by a mix of the respondent, leaseholders on long leases, shared ownership leaseholders and Housing Association sub-lets on short-term) were difficult to sell and mortgage due to the fire safety issues.

[edit] Building Safety related Orders

There are a number of different forms of Order related to the Building safety Act 2022, some of these are outlined in brief here with links to further articles.

Remediation Order : "made by the First-tier Tribunal on the application of an interested person, requiring a relevant landlord to remedy specified relevant defects in a specified relevant building by a specified time." Citation 30, in Part 5 of the Building Safety Act 2022; Remediation of certain defects, Section 123
Remediation Contribution Order : issued by the First Tier Tribunal "against certain corporate entities on the application of an interested person, so associated entities as such which may be required to contribute to the costs of remedying the relevant defects in the building within a specified time."
Building Liability Order : A mechanism that allows recovery rights relating to a building to extend beyond that of a subsidiary company (sometimes referred to as a special purpose vehicle) to its associated companies. Building Safety Act, 2022, in part 5, section 130.
Information Order : Gives claimants the right to apply to require a certain company to give specified information or documents relating to its associated companies. Building Safety Act, 2022, in part 5, section 132.
Costs Contribution Order : Mentioned in the Building Safety Act 2022 under the Cross Heading: Construction products: costs contribution orders (c. 30 Part 5).
Other related orders: The Fire Safety Order (FSO) or the RRO meaning The Regulatory Reform (Fire Safety) Order 2005.

[edit] Guidance criteria for higher risk buildings

Extract from UK Gov Guidance 'Criteria for determining whether a building is a higher-risk building during the occupation phase of the new higher-risk regime'

This guidance relates to the legal criteria for determining whether a building is considered a higher-risk building under the Building Safety Act 2022 and the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023. It relates to the definition of higher-risk building during the occupation phase of the higher-risk regime only.

"When counting storeys, any storeys which contain exclusively rooftop machinery or rooftop plant rooms should not be counted. Rooftop machinery is machinery which provides services to the building (for example, an air-conditioning system). Plant rooms are areas which contain machinery or equipment that provides services to the building. Only rooftop plant rooms and areas made up exclusively of rooftop machinery are excluded – for example, if floor three of a 7 storey building contained exclusively plant rooms and machinery, it should still be counted as a storey.

A storey must be fully enclosed to be considered a storey. The roof of a building should not be counted as a 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.

When measuring the height of a building, the building should be measured up to the top of the floor surface of the top storey that is not exclusively rooftop machinery or plant rooms. This is demonstrated in diagram 11."

Diagram 11 above to shows a 6-storey residential tower with a rooftop garden.

"In this example, height should be measured to the proposed floor surface of the top storey, as indicated by the arrow. The rooftop garden is not considered a storey, so the floor level of the roof should not be measured. Storeys should be counted from the first storey above ground. The proposed building in Diagram 11 has 6 storeys.

If the top storey is exclusively rooftop machinery or plant rooms, then the height of the building should be measured to the top floor surface of the storey below. This is demonstrated in Diagram 12.

Diagram 12 shows a 7-storey residential tower on sloped ground with a rooftop plant room.

In this example, height should be measured from ground level to the floor surface of the top storey, which is not a plant room, as indicated by the arrow. Storeys should be counted from the first storey above ground. The first storey in this building would not be considered below ground level as no part of its finished ceiling is below ground level for the overall building.

Based on the method for counting storeys in the Regulations, this building is considered 7 storeys and is a higher-risk building as it contains two or more residential units."

[edit] The Building Safety Act 2022, on higher risk buildings

The Building Safety Act 2022, section 65, sets out the meaning of ‘higher-risk building’ as:

"65 Meaning of “higher-risk building” etc

(1) In this Part “higher-risk building” means a building in England that—
- (a) is at least 18 metres in height or has at least 7 storeys, and
- (b) contains at least 2 residential units.
(2) The Secretary of State may by regulations make provision supplementing this section.
(3) The regulations may in particular—
- (a) define “building” or “storey” for the purposes of this section;
- (b) make provision about how the height of a building is to be determined for those purposes;
(c) provide that “higher-risk building” does not include a building of a prescribed description."

[edit] The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023

The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 made pursuant to section 65 are the relevant regulations of which the below state as follows;

"5.- (1) Subject to paragraph (2), the height of a building is to be measured from ground level to the top of the floor surface of the top storey of the building (ignoring 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).
(2) Where the top storey is not directly above the lowest part of the surface of the ground adjacent to the building, the height of the building is to be measured vertically from the lowest part of the surface of the ground adjacent to the building to the point which is a horizontal projection from the top of the floor surface of the top storey of the building (ignoring 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).
Storeys
6.—(1) Subject to paragraph (2), when determining the number of storeys a building has the following is to be ignored— (a) any storey which is below ground level; (b) 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; and (c) any storey consisting of a gallery with an internal floor area that is less than 50% of the internal floor area of the largest storey vertically above or below it which is not below ground level.
(2) Where a section is a building pursuant to regulation 4(2) or (4), any storey directly beneath the building which is not below ground level is to be counted in determining the number of storeys the building has.
(3) A storey is treated as below ground level if any part of the finished surface of the ceiling of the storey is below the ground level immediately adjacent to that part of the building."

113.12 Our investigations have shown that levels of competence in the construction industry are generally low and that by the time of the Grenfell Tower fire many contractors, designers and building control officers treated the statutory guidance as containing a definitive statement of the legal requirements. It is understandable that those who turn to the guidance for advice about how to comply with the Building Regulations should be tempted to treat it as if it were definitive, but that is a danger that the Secretary of State needs to recognise and guard against. We therefore recommend that a revised version of the guidance contain a clear warning in each section that the legal requirements are contained in the Building Regulations and that compliance with the guidance will not necessarily result in compliance with them.

113.2 As appears from the findings in our report, we are satisfied that the system of regulating the construction and refurbishment of high-rise residential buildings that existed at the time of the Grenfell Tower fire was seriously defective in a number of respects. The statutory guidance in Approved Document B was poorly worded and liable to mislead designers into thinking that complying with its terms would inevitably ensure that the building would comply with the legal requirements of the Building Regulations. The government department responsible for the Building Regulations failed actively to monitor the performance of the system and failed to ensure that dangers of which it became aware were communicated to industry. It was not sensitive to the need to make urgent changes to the statutory guidance if conditions required it.