The last few years have seen the NHS stretched further than ever – and over the past 2-3 years, it has rarely been out of the headlines. One of the less widely publicised challenges facing our health services, however, stems from its actual structures. It all comes down to the historic use of reinforced autoclaved aerated concrete (RAAC) in the construction of a number of hospitals and school buildings. This lightweight form of concrete was used primarily for roofs from the mid-1950s to the mid-1980s. It was seen as a faster, cheaper source of building manufacture, but it largely consists of air, leaving it vulnerable to moisture ingress and tensile deterioration.
The limited durability of RAAC structural components has long been recognised, with lifespans expected to be only 30 years, yet many are still in service four decades later. The sudden collapse of a ceiling at an Essex primary school, back in 2018, propelled the issue into the spotlight – and recent reports including those by the LGA and the DfE have suggested the problem may be more serious than previously recognised, with failures being recorded before adequate visual deterioration had been identified
Survey on RAAC
Last year the Department for Education opened a survey in relation to RAAC in school roofs, in a bid to better understand the prevalence of RAAC across the school estate. On the NHS side, hospital Trusts have worked hard to identify and implement emergency safety mechanisms – such as steel supports and props – to reduce the risk of collapse, and the Government has committed £110 m for temporary safeguarding of any affected hospitals. A directive has also been issued by NHS England/Improvement stating that all RAAC must be removed from NHS hospitals by 2035.
A rapid, cost-effective, and sustainable solution was needed to make sure that patient safety remained central to hospital operations. However, live hospital environments pose unique challenges, and replacing their RAAC roofing planks with modern, stronger alternatives has caused significant disruption for some. Where the issue was ‘resolved’ by simply adding structural steel supports, for instance, hospitals have reported a constant need to disrupt and relocate functions, along with a general sense of patients feeling unsafe. In some cases, Trusts have submitted bids to tear down and rebuild hospitals, rather than continue with replacement steel supports.
Surveying by the fabricator
The main challenge with steel reinforcement is that each RAAC plank needs to be surveyed by the fabricator – for which access to the affected areas of the hospital is needed. After this, a lengthy programme around the steel lead time needs to be implemented, so that delivery takes place on an agreed date when the area can be accessed for installation.
Given that the RAAC planks are in live wards, and even theatres, arranging access for set-in-stone dates is immensely challenging – the steel solution unfortunately falls short on the quick and flexible installation process front, while material shortages and cost increases also mean it is unlikely to offer the best value for money.
Recognising this, it was vitally important to the Morgan Sindall Construction team that we worked with others to create a more viable solution – one that could act as a blueprint for multiple hospital RAAC replacement projects around the UK. The opportunity came when we were appointed by the James Paget University Hospitals NHS Foundation Trust in Gorleston to help keep their structural RAAC planks safely, swiftly, and securely propped for years to come.
Working with the Estates Department at the James Paget University Hospitals NHS Foundation Trust and WSP, we took the solution right back to the drawing board, and locked down three key pillars for success:
1. A structurally sound and tested solution.
2. A quick and flexible installation process.
3. Best value for money
By grounding ourselves in the three key pillars we’d established, we developed a new solution utilising timber. While steel was the obvious first choice, timber quickly emerged as the best option, and challenging the status quo helped bring this to the forefront. In practice, the timber process involves drilling holes through existing downstand beams – scanning each plank to locate steel reinforcement, setting out in accordance with the structural engineer’s design criteria, and utilising a vacuum plate drill.
New timber beams, which have been cut to length, are then lifted into position either side of the existing downstand beam and drilled to align perfectly with those drilled previously. A 16 mm stainless steel Hilti threaded rod is inserted, with washers and nuts attached. Following this, domed-head nuts are fitted, and the timber decorated where visible.
In areas where existing services and obstructions prevent though bolts, Hilti studs are used to an amended structural engineer’s specification, and where enhanced structural solutions are required, timber ladders are also placed in between the timber beams to add further reinforcement. To complete the project, the beams are painted white to seamlessly match in with the roofing.
Unistrut framing
Further development utilises Unistrut framing suspended from the timber beams to support services and ceilings, thereby removing these existing loadings from the roof. With the comfort and security of hospital staff and patients front of mind at James Paget, we further developed the Unistrut frame to conceal sections within walls where occupant restrictions were required. Using this method means that, typically, 90% of works can be completed in two days – with the finished element requiring no unsightly or intrusive propping, and an estimated 70% faster than a steel alternative.
Respecting patients and the live hospital setting is of tantamount importance in projects of this type. Hospital refurbishment programmes need to be specifically tailored to avoid disrupting day-to-day operations. This means being able and willing to adapt project sequencing in accordance with evolving hospital needs. Experience is vital here, and our team is trained up for the sensitivity of acute care delivery. Having already nurtured a long working relationship with James Paget University Hospitals NHS Foundation Trust, we understood the need to protect patient privacy and dignity, and to tailor our approach so that the hospital could support positive patient outcomes.
The timber solution meant that the team could deploy the structural support mechanism at pace, yet be flexible around the changing landscape of the live hospital environment. There were numerous occasions where the challenges of COVID-19, patient surges, or emergency operations, required the construction team to re-programme the sequence of works, and – thanks to the speed and flexibility of the solution – it was possible to work this around the hospital.
Regular communication was invaluable, and the hospital heads of department had direct lines into the project team, to enable the flexibility to work around every patient need. The hospital strategically created a float of beds, which enabled the team to move these ‘spare beds’ around the hospital to make way for the RAAC works; without this it simply wouldn’t have happened. The project team also worked closely with the Trust’s Estates Department, and was ‘prepped’ to be ready to work in any area at short notice. This collaborative way of working was key to the project’s success.
The way forward
With the 2035 RAAC eradication directive now in place, and a pressing need for a flexible, but cost-effective solution to be implemented by the NHS, we hope that the method we employed in collaboration with James Paget University Hospitals NHS Foundation Trust will gain traction. Now tried and tested, the timber technique – when delivered in accordance with the blueprint that has been established – could be replicated at hospitals around the country, helping to solve the ongoing RAAC plank crisis, and relieving the NHS of at least one pressing burden. Most importantly, it is a solution shaped with the welfare of patients at its heart.
Alister Broadberry
Area director at Morgan Sindall Construction in the Eastern Counties since 2020, Alister Broadberry has over 30 years’ experience in construction. He has a wealth of experience on projects across a broad range of sectors – including health, defence, leisure, education, and residential. He started in the industry in 1990 as an apprentice. He continues to champion young talent in the construction industry, and now supports similar rotation schemes at Morgan Sindall Construction that he benefited from in his early career.
He joined Morgan Sindall Construction in 2004 as a Senior surveyor, progressing to Commercial director in 2012, before taking up his current role in 2020