The potential issues with RAAC (reinforced autoclaved aerated concrete) – a lightweight precast concrete frequently used in UK public sector buildings from the mid-1950s to the mid-1990s, are well documented. All NHS hospital sites in England with confirmed RAAC are now in NHS England’s ongoing national RAAC programme – allocated £954 m since the 2021-2022 financial year to enable the affected Trusts to implement remediation and failsafe measures. The challenges of remediation in a live hospital, with a particular focus on Airedale General Hospital near Keighley, were discussed in a four-way presentation at October’s Healthcare Estates conference. HEJ editor, Jonathan Baillie, reports.
Speaking in a Day One Estates and Facilities conference stream session titled ‘RAAC surveying, management and compliance’ were four personnel with considerable recent experience dealing with RAAC in healthcare settings. They were introduced by the session’s chair, IHEEM’s John Allwork, a strong supporter of IHEEM for many years, and a Chartered Engineer with over 38 years’ healthcare estates experience, now retired. The first to be introduced was Richard Burgin, RAAC Estates lead for Airedale NHS Foundation Trust, who is responsible for securing the future programme of works at Airedale General Hospital, and leads a team of project managers and surveyors remediating RAAC issues for the Trust. Richard Burgin is known as an ‘industry leader’ in RAAC, and is heavily involved in research and best practice published guidance notes. Co-presenting with him were Andy Buckley — Design director with Curtins; Oliver Organ — an Associate with Curtins who is considered a leading engineer in RAAC, and the current Project leader at Airedale General Hospital for delivering Curtins’ structural work, and Chris Waine, Project director at Hive Projects at the West Yorkshire hospital, who provides the Trust with ‘guidance to make informed decisions on capital and operational expenditure’.
Learning a lot on the journey
Curtins’ Andy Buckley began the presentation by setting the backdrop. He explained: “The process and assessment of RAAC and design considerations is something we’ve been involved with for at least the last 3-4 years across many estates and projects — none more so than at Airedale, and we’ve learned a lot on our journey. We will be talking through how that process of investigation and surveying has progressed, and what we’ve learned through institutions, working with suppliers and research bodies. We’ll also touch on the legal requirements of owners and occupiers, and generally about our lived experience at Airedale, applying it to practical and real-life applications.”
Explaining to delegates ‘why RAAC is a problem’, he said: “RAAC is still with us, and as a material it’s weak, low strength, and bends, and has only about a quarter of the density, and about one-tenth the strength, of traditional concrete. Unlike conventional reinforced in situ concrete, the reinforcement and the concrete don’t really act together compositely, so you don’t gain the strengths and benefits of that system. It doesn’t deal well with water, and indeed Richard and Oliver will touch upon the problems with cyclical environments throughout the seasons, and on water ingress, later.” Andy Buckley said RAAC had been ‘thrust into the news’ last year, largely through the schools sector, but ‘had been around’ for over 10 years, and, since 2019 particularly, the associated construction and estates community had really started to learn about it as a material and process. He said: “The latest known failure we are aware of occurred as recently as August 2024. It’s still a risk, and should be at the forefront of any estate’s mind.”
The Curtins approach
Here he passed over to his Curtins colleague, Oliver Organ, to talk through the company’s approach to investigating, assessing, and developing solutions for RAAC, and how the engineering consultancy establishes whether buildings contain it, using a combination of desktop surveys and visual inspections. He said: “We’ll explain how we undertake those inspections, what we’re looking for, and the key things we look to highlight, before focusing a little on the different solutions we’ve developed, using examples from Airedale General.
“So,” he continued, “to identify RAAC, we’ll usually start with a desk study — taking building records, historic drawings, and building manuals, reviewing historic site data, and establishing the age of buildings and when and how they were built, and what the forms are. Particularly,” he added, “we’re looking for flat roofs — one of the key aspects of RAAC, and inherently one of its risks.” Curtins typically undertakes visual inspections of the soffits to identify the material — a task completed either by a structural engineer or a qualified building surveyor. He explained: “Things we need to consider here include removing ceiling tiles, looking for services, and being aware of asbestos due to the age of the buildings. Almost all buildings containing RAAC have some asbestos. We also need to be thinking about the implications and risks of working at height.”
Approach to assessment
Curtins’ approach to assessment would, Oliver Organ explained, include non-intrusive surveys, measuring deflections, looking for crack patterns, water staining, and de-bonding of the soffit concrete. He said: “We might do some tap tests, and will also be looking for any builders’ work openings created post-construction — usually through repairs, remediation, ward refurbishments, and trying to squeeze new services into existing buildings.”
One of the key risks to become obvious in the last couple of years was cut planks, possibly without the right reinforcement or support conditions. Intrusive works, meanwhile, might include drilling at bearings, determining how much support the planks have at the bearing, and ensuring that they have reinforcement over the bearing. Oliver Organ said: “Over the last couple of years we’ve realised this is a critical detail, and if it’s not right, the planks can fail instantaneously, without warning, which presents a particular risk.”
Here, Oliver Organ began showing slides highlighting what engineers undertaking RAAC surveying and assessment might see. The first showed water ingress, with the RAAC planks heavily saturated, resulting in them getting heavier, and the reinforcement within them starting to corrode. He said: “So, those defects are compounded. You can see a rooflight on the right. In lots of buildings, particularly with NHS Trusts, the planks have been cut to make space for a rooflight, and are supported on the adjacent planks. We’re not sure — in many cases — whether they were designed for that extra loading, and even then, once they start to get saturated from water ingress around the planks, they get heavier, causing failures.”
Next, showing examples of ‘unsympathetic’ builders’ work openings, he said: “You can see cracks from them, and significant damage to the planks. What you’ll usually see — particularly with things like rainwater outlets — is that they’re leaking around them, because the concrete has spoiled, the rebar is exposed, and the water gets in and attacks it further.” Amidst all of this, Curtins looks for these defects, and then categorises them in accordance with the IStructE (Institution of Structural Engineers) guidance on RAG rating, looking particularly for high and critical risk planks, which the team will look to deal with immediately.
Some of the solutions
Turning to some of the ‘solutions’ deployed to date to address RAAC, Oliver Organ explained that ‘the most obvious or immediate’ — where there was a safety issue — was to close the area, recommend propping, and possibly remove loading if it’s a roof, factoring in emergency limits on the load, and allowable loads. The objective here is to address and minimise the immediate risk, so Curtins can then develop solutions. Such future solutions could include removing the planks entirely, although, ‘more often than not’, Curtins was seeing the affected RAAC planks supported, at least in the interim, until a wider programme of repairs could be implemented — be that repairs, replacing the building, or ‘a more significant roof repair’.
The Curtins Associate next showed slides from the work ongoing at Airedale General Hospital. “So,” he explained, “we have a few different solutions for a full remedial repair — such as timber ladder frames parallel to the planks, providing full positive support to the planks, or possibly a hybrid solution — where we have steel beams and timbers spreading the load between the beams. Working at Airedale, in particular, we have realised that those remedial solutions are very time-consuming. The amount of services and finishes to those areas you have to remove is both time- and cost-prohibitive.”
Curtins’ team had thus looked to develop ‘a more targeted approach’. Oliver Organ elaborated: “We are still, in many cases, decanting wards at Airedale to be able to do this work, but we’ve tried to be much more targeted, and to focus on the ‘red’ and ‘amber’ planks — to save time and get the programme completed faster. We were looking at it taking 12 months per ward initially, and now we’re down to eight — which has brought the RAAC repair programme completion forward to 2028, ahead of the 2030 target.”
“Here,” he added, showing other slides, “we have pictures of some of the more targeted repairs. We’re putting timber ladders under the worst case planks, and end-bearing enhancements to all the ends of planks where they meet beams, to eliminate that instantaneous failure risk. Where possible, we are also using existing structure to support the timbers.” He continued: “In the picture on the right you’ll steel PFCs (parallel flange channels) spanning across the corridors — original steelwork used to support services. We’re now repurposing this to support timbers that, in turn, support the RAAC.” This had been another contributor to speeding up the programme, because while the team had still had to remove a lot of services, it had to remove less than first expected.
‘Bespoke’ RAAC management strategy
Alongside the remedial solutions Curtins is providing, its team has also developed various management documents and strategies with the Airedale team. Oliver Organ explained: “We’ve produced a bespoke RAAC management strategy that describes how we will get from where we are now to a safer building, and which areas we will prioritise first, and how. We’ve also developed emergency procedures, for use in the event of a failure or other incident. In addition we’ve undertaken reviews around the estate on roof loading, and given advice to contractors who might be working on roofs, looking at what loads the buildings have been subjected to. Can we reasonably assume that those loads can continue to be supported?” Here, Oliver Organ handed over to the Trust’s Richard Burgin, for some additional detail on the safe system of work that Airedale and the Trust have developed jointly ‘to keep the hospital safe’.
Beginning his part of the presentation, Richard Burgin noted that that Airedale General Hospital is England’s only hospital (known) to have substantial RAAC, with the entirety of its ground floor formed from RAAC panels. He explained: “We’re in the UK’s eighth wettest location, with the largest flat roof in the NHS, and — as Oliver touched on — standing water and flat roofs are typical of RAAC construction from the period. There is also an inherent risk of moisture ingress into the panels, which dramatically affects their ability to carry load.” He continued: “We’re also the only hospital — we think — that has identified issues in our ordinary concrete frame and the corbels — the pre-cast elements of the structure that have significant structural challenges in too. We’ve just over 19,000 planks under load, with an additional 8,000-9,000 internal and external wall planks; that’s the scale of the problem we’re dealing with.”
Richard Burgin went on to explain that since the since the SCOSS (Standard Committee on Structural Safety) alert on RAAC came out in 2019, the Trust had undertaken its own survey, supported by Curtins, to assign a risk profile and defect rating to each plank, and that it continues to monitor this using its in-house team. He added: “Again, I think we’re the only Trust in the NHS that looks at that inspection and monitoring regime with internal resource. We then identify change to Oliver and his Curtins colleagues so that they can come and assist us with decision making and remediation selection.”
Following the initial survey of all of the hospital’s floors and roof planks, the Trust built a team ‘in house’ to address the problem using existing maintenance resource. Richard Burgin explained: “We believe that compared with other similarly-sized NHS estates, we’re saving around £500,000 using the internal resource model, rather than having a consulting engineer doing all the day-to-day inspection and monitoring. Working alongside Curtins, we’ve established a system of work that incorporates the survey methodologies, the Standard Operating Procedures, and the hierarchy of defect strategy documents that Oliver showed you in his previous slide.”
The Trust team had also, he explained, developed a ‘dynamic inspection tool’ that enables it to increase inspection frequency if the effects presented in the panel appear to have deteriorated, as team personnel move towards establishing whether or not they need to mitigate and remediate a particular plank. “Simultaneously,” he added, showing a slide from the ‘inspection tool’, “there you can see the different risk profiles listed on the right hand side, and the frequencies on the map. That buys us the time.”
The Trust RAAC Estates stressed that one of the elements his team must continuously consider is the business continuity of the estate, and the clinical operational function. “So,” he explained, “while ideally we’d close the entire estate, remediate the problem, and then re-open it, that can’t happen here because of the nature of the business we’re in. Instead, we must us all the tools available to manage the risk safely while maintaining business continuity.”
Former paper-based approach
From 2019 until 2022, Richard Burgin explained, the system of inspection had been supported by a paper-based approach, with printing out of the existing asset drawings, which were then marked up, with a fully numbered panel drawing produced of every one of the 50 departments. The result was that all 19,000 panels were risk profiled and displayed on a set of CAD drawings. He took up the story: “We then printed out inspection pro formas and sent the team out onto the wards to complete the task of inspecting.” Currently, he explained, the team undertakes around 70,000 inspections annually. He said: “That then led to a series of challenges — for instance around infection prevention risk, with us carrying pieces of paper from one ward, and one room, to another. We also have health and safety issues around accessing the soffit of the planks with step-ladders, carrying boards, holding huge reams of paper, and trying to keep it all in order.”
With around RAAC 500 panels per department, this work proven a considerable logistical challenge. Richard Burgin explained: “We had storage and sustainability issues linked to the use of paper and record-keeping for the audit trail, and then realised the information was all being double handled. The survey team was going out completing the inspections, with the data brought back and passed to an administrative function to be uploaded onto Excel — the format we were using to keep the spreadsheets.”
An ’emerging field of understanding’
With 50 separate Excel sheets, and 20,000 lines of data, it had then become ‘hugely time-consuming’ to update after any changes in guidance. “We are also operating in an emerging field of understanding around RAAC as a material, so any change in guidance meant reconfiguring the entire system, changing the ratings of everything manually, and then going out and re-inspecting,” Richard Burgin explained. “That made us realise we needed to change the way we were doing this, and we looked to digitise the process. We contacted a company called BIS Consult and set about digitising our inspection and monitoring process.” Here he showed a slide incorporating a pictogram of the existing process at the top, and the the new process at the bottom.
He further explained: “We developed this process map to see where to identify the pain points in the existing system, and how we could rectify that, and indeed add to the process flow using the digital process. Essentially — as you can see in the middle — we know we’ve achieved a 50% efficiency saving in two full-time equivalents in the administrative function. That provides the return on investment for investing in the digital solution.”
The benefits of ‘going digital’
Moving to ‘the outcomes and benefits of going digital’, Richard Burgin said — illustrating his point via slides: “So, we’ve got the efficiency, it’s all done live, using GPS, cloud-based technology, and iPads. As a panel risk rating changes, it updates live, and changes the dashboard and the metrics. We have the resilience of it all just working. It also sits on the clinical Wi-Fi, and we’re not relying on pieces of paper, having the inspection packs put together and processed, to then be taken out, disassembled, filled in, and then reprocessed. It’s all just touch and tap on the iPad, and a fully audited process.”
Every inspection is date and time stamped, with a full log of who has undertaken the work, Richard Burgin explained, which also assists reporting. He said: “The system acts as a single source of truth, so we can configure that metric to report any different parameters. We know exactly how many of the highest risk planks we’ve got, and how many we have no risk evident in, the total number of planks; and all such data. It’s very useful for that reporting function and indeed — given how it operates — given access to it, external stakeholders can come into the system on a ‘view only’ license, and take all the information out for themselves. We thus don’t have to provide NHS England with updates; they can take the data out for themselves.”
From a health and safety standpoint, meanwhile, with the system GPS-based, Estates management personnel know where the operatives are, and whether they are lone working. Richard Burgin said: “It’s also a really useful health and safety tool in terms of translating that risk onto the roof. These are the new capabilities we were developing previously. While it was all paper-based and on Excel, now it’s digital and updates live, and we have connectivity across the estate.” He continued: “We can see who’s logged on, and change the profiles at will. Previously, we had to update all that manually, but it now updates itself. If we have a change in guidance, we can feed the data into the software, and it then changes all the risk profiles.”
Touching next on data analytics, Richard Burgin explained, using a slide: “The third image there is the dashboard based on the infographics from the NHS guidance document produced by Mott MacDonald; it’s really straightforward and easy to read, and you can see the risk at a glance. That’s great for communicating out to external stakeholders, in particular, who may not be as interested in RAAC as I am. It’s really powerful messaging. You can see it at glance — the biggest estate in the NHS captured on one screen of information.”
The final image Richard Burgin showed was of the roof access tool, where the Trust team has taken high-resolution drone survey imagery and overlaid its roof layer of RAAC risk. When operatives are working on the roof, the system can tell them when they are about to stand on a high risk plank — locating them using geo-gate technology — and informing them they’re about to enter a high risk area. He explained: “This is really important part of our strategy moving forward with PPMs; we’ve so much of our electrical infrastructure on the roof. It’s an essential piece of health and safety kit for us, and also helps with extreme weather inspections. We can plot rainfall, see ponding on the imagery, and target roof leaks, which — as we know — are going to become more of an issue.”
Here Richard Burgin handed over to Hive Projects’ Chris Waine, who began: “Part of our role as Project and Programme manager has entailed running regular ‘lessons learned’ sessions, and capturing some of the success stories. For example, to date we’ve remediated over 22% of the estate, over 4000 planks, while retaining about 98% occupancy in the hospital. We’ve had zero health and safety incidents — which we’re proud of, particularly given the programme’s nature. Richard has already touched on the ‘in house’ survey capability. Aside from the financial benefits, we’ve created pathways for internal members of staff to develop and progress.
“Notable too,” Chris Waine said, “has been familiarity in a hospital environment. So if — when walking around the estate — operational people see familiar faces, they’re much less anxious, as opposed to encountering external people coming in with PPE and hats. It’s a stressful environment as it is, so there’s real benefit in that, and we’ve measured the impact through the staff survey.” He added: “We have a very mature team, of which Hive and Curtins are part, as are Shelby Group. “
Financial aspects
There was also — Chris Waine noted — a multidisciplinary design team working on the programme. He said: “In financial terms, the programme cost is about £20 m annually, of which 50% is down on the ward decant programme, where Robertson Construction is our main contractor. As Oliver explained, what we’ve done through the lifecycle of the programme is rationalise the base scope of service, reducing the capital cost per ward from £5 m to £2 m, but probably more importantly, it’s shortened the programme by about a third per ward.”
He continued: “We’ve also brought the overall completion date forward by two years, which is clearly important in this environment, and with a project roadmap and business case framework, we’ve structured and streamlined some of our processes. It’s very efficient as a delivery model. We in fact have to submit a short-form business case annually to secure the circa £20 m in funding, and in some instances we do this mid-year — so if there’s slippage across the NHS, we can potentially tap into additional funding.” The project team had in fact done this successfully, with a ‘100% success rate’ on the business case process.
Chris Waine went on to explain that, ‘as with any good public sector project’, we have a workstream around social value, ’embedding that in everything we do, and particularly around procurement’. He said: “We have a social value charter as part of the appointment of Robertson as our main contractor, and it’s also embedded in procurement of local supply chains.” He elaborated: “So, we’re using local firms for some of the targeted remedial works, and investing in the local community.
“Richard has already talked at length about the digital twin,” Chris Waine added, “and we had NHS England on site last week, and have been talking to them about how it can be used more broadly across the NHS. Airedale is one of seven RAAC Trusts to go through the New Hospital Programme, so the digital twin is being evolved and developed, and will be part of the NHP journey as we go forward.”
The Hive Project speaker next noted — on the subject of research and innovation: “The digital twin came about as part of that agenda on the programme, and we’re working with people like Loughborough University and the Manufacturing Technology Centre in Coventry to look at other opportunities to innovate around the programme.” Chris Waine said the latest was around the use of sensor technology. He explained: “We’re talking to MTC about how we can use sensors in the live environment to measure certain factors that affect the RAAC. It’s a technology that’s actually quite mature in the aviation sector.”
The team’s proposition
His last slide, he explained, was about the AGHS ‘RAAC Proposition.’ He elaborated: “Airedale General Hospital Solutions is actually a Trust subsidiary, and as part of the discussions with NHS England and other partners, we’ve offered help and support with RAAC to others. For example, we have a very mature surveying and inspection capability, and people have been reaching out for help and support to train members of staff in NHS or other public sector environments. We also have Standard Operating Procedures, validated by the Institution of Structural Engineers, so can help organisations embed them, and get the necessary assurance in place to discharge that. We have the digital twin already, and some organisations are interested in using it and complementing it with the SOPs.”
Chris Waine continued: “We obviously have a multidisciplinary team that can be lifted, shifted, and deployed, anywhere there’s a RAAC issue. All this has been through a procurement process, and involves not just the consultancy side, but the contracting entities too. The final point,” he said as the presentation ended, “is around the business case and cash flow forecasting. Clearly many in the NHS are familiar with the business case process, but what’s unique about the Airedale General team is that we have a lot of both learned experience and cost data. When people are putting business cases together, we can thus help with and support that process. If anyone is interested in that help and support, please speak to Richard or I after the event.”
With this, Chris Waine’s part of the presentation, and an interesting session on RAAC, the safety and structural problems it poses in public buildings such as hospitals, and some of the most effective methods of dealing with it developed to date, closed, and John Allwork thanked the speakers, and invited questions from the audience.