Reinforced autoclaved aerated concrete (\u201cRAAC\u201d) is a lightweight cementitious material pioneered in Sweden and used extensively in walls and floors of UK buildings from the 1950\u2019s to 1990\u2019s.\u00a0 Mixed without aggregate, RAAC is \u2018bubbly\u2019 in texture and much less durable than standard concrete, with an estimated lifespan of 30 years.\u00a0 The air bubbles can promote water ingress, causing decay to the rebar and structural instability.<\/p>\n
RAAC is often coated with other materials and may be difficult to detect from a\u00a0visual inspection. \u00a0Invasive testing will often be required to investigate the condition of affected areas and evaluate operational risks. \u00a0In some instances RAAC structures have failed with little or no warning, posing a significant risk to owners, employees, visitors and occupants. \u00a0Aging flat roof panels are especially vulnerable from pooling rainwater above.<\/p>\n
Buildings insurance is designed to cover damage caused by sudden and unforeseen events, whilst ordinary \u2018wear and tear\u2019 is treated as an aspect of inevitability and usually expressly excluded.\u00a0 Where damage occurs, it will be a matter of expert evidence as to the relative impact of contributing factors.\u00a0 English law recognises a critical distinction between failure due to inherent weakness of insured property, and accidental loss partly caused by external influences.\u00a0 Depending on the specific policy wording, unexpected consequences of a design defect or flawed system adopted by contractors may provide the requisite element of fortuity, notwithstanding the concurrent effects of gradual deterioration under ordinary usage (Versloot Dredging BV v HDI Gerling (The DC Merwestone) [2012];\u00a0Prudent Tankers SA v Dominion Insurance Co (The Caribbean Sea) [1980]<\/em>).<\/p>\n Original designers and contractors responsible for RAAC elements in affected buildings in many cases will no longer exist, adding further complexity to potential liabilities.\u00a0 Given that the widespread use of RAAC ended in the 1990\u2019s, it is likely that limitation (even under the new 30-year period for Defective Premises Act claims, if applicable) will have expired, though a fresh period for bringing such claims can be triggered where subsequent refurbishment works have been carried out. \u00a0To the extent that RAAC related claims are not time barred, professional\u00a0indemnity insurance may respond subject to operation of any relevant policy exclusions.<\/p>\n