The Building Safety Regulator (BSR) has recently issued a warning to principal accountable persons and buildings owners in England of a potential structural safety issue affecting reinforced concrete buildings constructed with ‘transfer slabs’, which have been used in mixed-use buildings throughout the UK for the past 25 years.
This article explores the BSR's recent warning about potential structural risks associated with reinforced concrete transfer slabs. It explains what transfer slabs are, why they may pose a danger, and what building owners need to consider from both a safety and legal perspective.
Reinforced transfer slabs are floor arrangements where a load bearing column sits on top of a thickened reinforced concrete slab without a supporting column underneath. The slab acts to support the load from the column and spreads it to the columns below. The government has stated “Specifically, there is a concern regarding 'punching shear in transfer slabs', a failure mechanism where a high concentration of load causes a column to punch through a reinforced concrete transfer slab. This may result in a collapse in part of a building”.
Reinforced transfer slabs have been commonly used in reinforced concrete buildings to facilitate the transition from one column grid in the lower section of a building to another grid higher up the building. Using transfer slabs allowed designers to create open spaces, such as car parks, beneath either commercial or residential units.
Transfer slabs are not limited to a specific type of building and so have been used in both residential and commercial buildings. This is, understandably, a concern for building owners across the country.
The BSR is working with industry experts and the Ministry of Housing, Communities and Local Government to better understand the extent of the risk, and how the risk can be identified and managed proportionately in existing buildings.
As the risk of punching shear is an emerging issue, further investigations are being undertaken by the government with guidance to be issued once investigations have concluded.
The government has stated that the presence of a transfer slab alone “should not require a building to be decanted”. It's likely that further assessment considering other risk factors will be needed to determine if there is a risk to building residents. The BSR recommends that where there are visible signs of distress or specific concerns regarding a building’s condition or design, building owners should seek immediate professional advice, i.e. from a chartered building surveyor and/or chartered structural engineer.
Where a defect is identified this raises the critical question of who should foot the bill, and to what extent contractors and consultants could be liable where they have been complicit in installing or specifying reinforced transfer slabs. Assigning responsibility and cost is often a complex process and is rarely straightforward. Responsibility will always hinge on the cause of the defect and the contractual matrix.
There could be one or several culpable parties, including architects, developers, contractors and potentially surveyors.
Should a building owner face risks of shear punching in transfer slabs, one of the largest hurdles they may face relates to limitation. Statutory limitations are a hurdle for any claim for alleged breach of contract and/or professional negligence. Where a defect has been established, and the negligent party identified, such limitation periods will need to be carefully considered.
The Limitation Act 1980 requires a potential claimant to bring a claim within six years, where a contract is signed ‘under hand’, or twelve years, where a contract is executed as a deed. The limitation date is usually calculated by reference to practical completion. This is particularly relevant to transfer slabs as this type of design has been used for the past 25 years and there will inevitably be circumstances where works were completed more than 12 years ago, meaning the contractual limitation periods are likely, in many cases, to have long since expired.
The Building Safety Act 2022 offers important protections for leaseholders and owners of residential and mixed use buildings that contain a dwelling. It does this by extending the time limit for claims under the Defective Premises Act 1972 to 30 years, applied retrospectively. However, these benefits do not extend to owners or interested parties of non residential buildings.
For claims in negligence the limitation period is either six years from the date of damage caused by the negligence, or three years from the date the damage was or should reasonably have been discovered, subject to a longstop period of fifteen years from when the works were originally completed. Again, the limitation period for a claim in negligence is also likely to have long since expired for works that completed in the earlier years of transfer slabs being used.
It's still very early days and the focus at the moment remains on investigating the issues further and in time, procuring, pricing and possibly implementing any remedial schemes or temporary remedial schemes in the short term. It's still unknown at this stage, however, whether simply the presence of transfer slabs is sufficient to be considered a defect or if it's only buildings where there is a risk of punching shear that will be affected.
The Building Safety Regulator’s notice is available here. For further information, please contact our construction team.
