Higher-Risk Building Definition: Is Your Project in Scope?

The question usually arrives as one line in an email, and it sets the next twelve months of your programme: can you confirm whether this building is higher-risk? It comes from a main contractor's design manager, a client's project director, or your own commercial manager reading a Gateway 2 clause in a contract that has just landed. Nobody attaches the reasoning. They want a yes or a no, and whichever one you give, somebody is going to rely on it.

What's Actually Being Asked

"Higher-risk building" is a defined term, and the first thing to know is that it is defined more than once. The Building Safety Act created two regimes that use the phrase, and they do not draw the line in exactly the same place.

For design and construction, the regime that brings in the gateways, the additional higher-risk dutyholder requirements and the golden thread, scope is set by the Building Safety Act together with the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023, which supply the building descriptions, the exclusions and the measuring rules. Broadly, a building is higher-risk if it is at least 18 metres in height or has at least seven storeys, and it contains at least two residential units, or it is a care home or a hospital meeting that height or storey test. For the in-occupation regime, the one that brings registration with the Building Safety Regulator, an accountable person and a safety case, the same height and storey test applies with at least two residential units, but care homes and hospitals are not carried over. A hospital can therefore be in scope while it is being built or altered, and outside the in-occupation regime once it is in use.

The regulations also carve out certain uses, but only where they account for the whole building: among them hotels, secure residential institutions such as prisons, and military barracks or forces accommodation. A building that merely contains one of those uses is not carved out. The regulations also set out how to measure, which is where most of the real arguments live:

• Height is measured to a floor, not to the roof. The measurement runs from ground level to the floor surface of the top storey, so a parapet, a plant enclosure or a lift overrun does not on its own push a building over the line.
• Not every level is a storey. Storeys below ground are not counted, and a roof-top level that exists only to hold plant or machinery is ignored. A gallery or mezzanine counts only once it is large in relation to the largest storey directly above or below it, rather than the largest storey in the building, and the regulations set that proportion.
• One address can be more than one building, but not yet. Once a building is occupied, a structure with independent sections can have each section treated as a separate building, which is why one address can carry more than one registration. While the building is being designed and constructed that split does not apply, and the structure is assessed as a whole. A scheme that will later be two buildings is one building at Gateway 2.

Two more things are worth knowing before you answer the email. Other parts of the Act use different thresholds for different purposes, most visibly the eleven-metre and five-storey line that runs through the remediation and leaseholder protection provisions, so "in scope" only becomes a useful answer once somebody says in scope for what. And the dutyholder and competence duties added to the Building Regulations in 2023 apply to building work in England generally, not only to higher-risk work. A no on the height test is not a no on having to show that the people doing the work were competent to do it.

What follows is how the regulations frame the question, not a view on any particular building. Where a scheme sits near a threshold, the determination belongs with the dutyholders and their advisers, which is exactly why it is worth recording properly.

The Evidence That Answers It

The answer to a scope question is not a word in a reply. It is a determination someone can follow later, when the person who made it has moved on and the drawings have moved on with them. In practice that means a short, dated record holding:

• The measurement, and how it was taken. The ground level used as the datum, the storey identified as the top storey, and everything excluded from the count with the reason: the plant level, the basement, the mezzanine that did not reach the threshold.
• A storey schedule and a unit count. Each level listed with what it contains, and how many residential units the building has, with the definition applied rather than assumed.
• Use and building type. What the building is, whether an excluded use covers the whole of it, and how the structure is expected to divide into separate buildings once it is occupied.
• The drawing revisions it rests on. A determination taken from a superseded general arrangement is a determination about a building that no longer exists.
• Who decided, when, and on whose instruction. If the client or the principal designer gave you the answer, keep the instruction and the version of it you relied on.
• What would change it. The design moves that trigger a re-check: a level added, a plant deck gaining a room people work in, a gallery grown past the threshold, use changed from commercial to residential, residential units introduced where there were none.

Why the Spreadsheet Version Fails

Nobody writes this down, because on the day it feels like arithmetic rather than a decision. The answer goes out in a reply, the reply lands in a folder or nowhere, and the conclusion enters the project as folklore: everyone knows this one is not higher-risk, and nobody can say who established that, from which drawing, or on what date. Then the scheme does what schemes do. A storey is added. The plant deck gains a room somebody will work in. The commercial level at the top becomes apartments. The original determination stays true about the building that was drawn in the spring and turns quietly false about the one being built in the autumn, and the person who could have told you which revision it came from has moved on. If the question is ever asked again in earnest, by a regulator, an insurer or a solicitor, the difficulty is rarely that the building was borderline. Borderline is ordinary. The difficulty is that the resolution was never recorded.

Keeping It Provable

The fix is unglamorous: treat the scope determination as a record of the building rather than a message about it. Written once, anchored to the building it describes, carrying the revision it was taken from along with the date and the name, and re-opened whenever a change touches height, storeys, units or use. It costs an hour at the start of a job, and it is the difference between answering a question years later in a sentence and reconstructing a decision from a mailbox. The discipline pays twice, because if the answer is yes, the golden thread starts that week, and a project already recording decisions against the building it is putting up has somewhere to keep them.

The Monday Checklist

1. List every live job and every tender, and write the scope answer next to each one. The blanks are the work.
2. For each yes and each no, go and find the determination behind it. If it is an email, it is not a record yet.
3. Check which regime each question was actually about: design and construction, occupation, or one of the Act's other thresholds. Answer the one you were asked.
4. Re-take the measurement on anything within a metre or a storey of the line, from ground level to the top storey floor, and note what you excluded and why.
5. Confirm the drawing revision each determination rests on, and check whether that revision is still current.
6. Agree with the client or principal contractor who owns the determination and who re-checks it after a design change, then put that agreement in writing.
7. For everything outside the higher-risk threshold, check your competence and dutyholder evidence anyway, because those duties do not begin at 18 metres.

Where BrieXO Fits

BrieXO's FIELD bundle keeps daily site records, inspection and QA workflows, photo evidence, competence records and recorded decisions in one living record, anchored to the building, so a scope determination and everything that follows from it sit with the work they describe rather than in a mailbox. Design and commercial modules are on the roadmap. It supports your dutyholder duties; it doesn't discharge them, and nothing in it decides whether a building is higher-risk. How that record maps to the Act is set out on our Building Safety Act compliance software page.

Related reading:the evidence Gateway 2 asks subcontractors for, the specialist contractor's guide to the golden thread, and who evidences what, package by package.

George Sfica is a senior design manager at a specialist façade contractor, with 23 years in manufacturing and construction, eleven of them in façades and external envelopes, spanning fabrication, installation and design management, an MSc in Façade Engineering and an IFE Level 2 Certificate in Passive Fire Protection. He is the founder of BrieXO.