REPAIR AND REMEDIATION
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
February 2025 Health Estate Journal 49
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
The ‘size of the (RAAC) problem’ at Airedale General Hospital clearly illustrated.
Left to right: Andy Buckley and Oliver Organ from Curtins, the RAAC Estates lead for Airedale NHS Foundation Trust, Richard Burgin, and Hive Projects’ Chris Waine.
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