Building Safety Regulator guidance on transfer slabs

You’ll see a new note today from the Building Safety Regulator, part of the Health and Safety Executive. Published on 19 December 2025, it highlights potential structural risks in some reinforced concrete buildings that use ‘transfer slabs’. It applies in England and speaks directly to principal accountable persons and building owners who make safety decisions day to day.

Let’s keep the definition clear. A transfer slab is a thick floor that carries columns above even when there are no columns directly below, spreading loads to supports elsewhere. You often find this in mixed‑use buildings where the grid changes between a shop or car park level and the flats above. Engineers have used this approach in the UK for more than 25 years, and most buildings built this way perform as intended.

Why this update now? In November 2024, the Institution of Structural Engineers released new guidance for designing transfer slabs in new projects. That document sharpened attention on how engineers check punching shear and design for robustness today, while noting that assessing existing slabs sits outside its scope.

The specific worry is punching shear: if loads concentrate at a column, the column can push through the slab and cause a localised collapse. Regulators add an important point of reassurance: they are not aware of any UK building collapses from this mechanism. The instruction is to review and manage risk proportionately, not to alarm residents.

What should owners do right now? First, establish whether your building contains a transfer slab. If you see visible distress-cracking, unusual deflection-or you lack confidence in the original calculations or detailing, bring in a competent structural engineer. Presence alone is not a reason to decant residents; decisions should follow a risk assessment.

For residents and for students learning how structures work, here’s the short version. Transfer slabs are a normal feature of many buildings. The regulator wants owners to check that older examples still meet expectations and to act where necessary so that people can remain in their homes where it is safe to do so.

This sits alongside the safety case approach introduced by the Building Safety Act. A safety case report for a high‑rise should set out structural risks and how they’re being managed, with clear evidence and version control. If a transfer slab is present, record it, summarise the design intent, note uncertainties, and set a plan for monitoring or investigation.

On the regulator’s side, BSR commissioned independent research in late 2024 and consulted its Building Advisory Committee. It is working with the government’s housing department and industry to agree proportionate ways to identify and manage any risk in existing stock. Updates will come through BSR email bulletins and the Making Buildings Safer website.

Talking to residents is part of good safety practice. Share what system your building uses, what checks you’re commissioning, what the timeline looks like, and when you’ll report back. Keep language plain and keep a named contact so people know exactly how to raise questions and get answers.

If you’re commissioning an assessment, your engineer may start with drawings and calculations, check slab thickness and reinforcement around columns, and consider whether loads have changed over time-new plant, façade upgrades or a change of use. If information is missing, your safety case should state what you did to find it and what further investigation you plan.

A quick myth‑buster for class discussion and team briefings. A transfer slab is not a danger sign by itself. Some cracks are expected; others signal distress-engineers can tell the difference. New guidance for designing future buildings does not automatically condemn older ones; it is a prompt to review evidence and act in a proportionate way.

Your practical checklist for the week is simple: identify any buildings in your portfolio that use transfer slabs, brief your resident liaison team, line up a competent structural engineer if you have concerns, and subscribe to BSR updates so you don’t miss further advice.