We are aware of the Building Safety Regulator’s recent advice to building owners with regards to modern buildings containing transfer slabs. (These are thick, flat concrete floor plates between two differing column layouts in a building that support the upper columns on the lower columns).
In November 2024 the Institution issued guidance, “Design of transfer slabs” on how to design these types of structure in new buildings. The guidance was in response to research by the Institution and CROSS, the industry voluntary safety reporting service operated by the Institution. This research identified the design of transfer slabs as a highly complex area, not explicitly covered by Design Standards. This has resulted in an inconsistent approach to design. The IStructE guide offers a consistent and robust approach for new build structures.
Following the introduction of the Building Safety Act 2022, owners of Higher Risk Buildings (residential buildings of greater than 7 storeys or 18m) have been required to assess their existing buildings for fire and structural safety. As part of these assessments, engineers are also reviewing transfer slabs. The Institution has provided extensive and detailed guidance to assist engineers in this process:
These references describe what and how to assess existing structures and to determine if further action is required. The Institution is working on a guide on the assessment of the existing transfer slabs. The Institution will also publish “Preparing safety case reports for higher-risk buildings under the Building Safety Act” in early 2026 to guide structural engineers through the HRB assessment process.
If building owners believe that they have a transfer slab that requires assessment they should contact a structural engineering company with experience in the subject and follow the above guidance: findanengineer.com.
- ends -