Pioneering structural risk assessments for higher‑risk buildings

When the Building Safety Act 2022 came into force, it reshaped the responsibilities of building owners and the wider built‑environment sector.

The Act identifies the need for a Safety Case Report to be produced by the Principal Accountable Persons (PAP) for all existing higher-risk buildings (HRBs). These documents outline how building safety risks, including fire spread and structural failure, are being identified and managed for all occupied HRBs.

With 12,500 existing HRBs in the UK, the industry lacked clear guidance on what a Structural Risk Assessment (SRA) should look like or how it should be performed.  

Faced with a regulatory framework rich in intent but sparse in detail, we stepped forward and developed a robust way of ensuring structural safety.

Our involvement

In October 2024, while assisting a major property operator developing their Safety Case processes, Cundall was invited to contribute. With no existing structural risk assessment frameworks to refer to, we built our approach from scratch using the underlying process established in the publication entitled “Manual for the systematic risk assessment of high-risk structures against disproportionate collapse” produced by the IStructE.

This process involved a full risk assessment of the existing structure to identify potential causes of local or global failure, scoring each risk by likelihood and impact, to determine tolerability. Where risks were not tolerable, mitigation measures were defined. Following the UK-Spec HRB guidance, as low as reasonably practicable (ALARP) principles were applied to assess and reduce risks. This in turn allows us to demonstrate to the PAP that “all reasonable steps” have been taken to control risks and that proportionate measures have been exercised. Each building review included independent Partner oversight to minimise confirmation bias, which is considered essential to ensuring the best outcome for building occupants. 

The process

To bring rigour and repeatability to an undefined process, Cundall established a four‑stage methodology:

1. Data gathering

We spent time educating PAP's on the data they should have available on their buildings, highlighting the importance of comprehensive information from the outset to allow us to complete our reviews.

2. Desktop review

This information forms a detailed reference point for the first structural review, helping to identify early hazards and gaps in knowledge before site attendance.

3. Site visit

A visual inspection of all accessible areas of the building to confirm as-built drawings and assess the condition of the existing building.

4. Hazard identification (HAZID) review workshop

A workshop to evaluate all identified risks, scoring each for likelihood and consequence, attended by a diverse group of engineers. This is where ALARP principles are applied, mitigation is agreed, and independent Partner oversight protects against confirmation bias.  

Engineering judgement  

Much of what we do involves “reverse engineering” how a building works, reconstructing its vertical and horizontal load paths, the approach to robustness, durability and the like from drawings and inspection, rather than having a set of defined calculations to work from.

The work has also often sat at the intersection of structural and fire engineering. In many cases, Cundall assesses structure against codified requirements, while Fire Engineers provide analysis of protection systems and fire strategy performance. The result is a collaborative, iterative approach to building safety, where specialist insight strengthens the outcome.  

This process continually tests engineering judgement, balancing subjectivity, proportionality, and technical know‑how.

The future of structural risk assessments

Since developing the first template, Cundall has produced over 100 Structural Risk Assessments, many already approved by the Building Safety Regulator despite a national backlog. Our approach has been refined continuously in response to BSR feedback, PAP expectations, third‑party reviews, and collaboration with the IStructE. 

To maintain consistency across a growing portfolio, we developed an internal AI agent which identifies risk patterns across buildings with similar traits. This enables faster review, greater standardisation of mitigation measures, and improved cross‑portfolio insight.

Formal guidance was issued last week by the IStructE and we will continue to refine and align our processes to suit. Our focus remains on competence, consistency, and meaningful collaboration across disciplines. With our growing database of completed assessments and an established internal knowledge ecosystem, we are well‑positioned to help shape best practices for years to come. 

See how we can support and strengthen the structural component of your Safety Case Reports. Learn more here.