NDTScan carries out RAAC surveys in Colchester for schools, hospitals, councils, housing providers, universities and commercial owners. Reinforced autoclaved aerated concrete was used in roofs, floors and walls from the late 1950s to the mid 1990s, and a great deal of it is still in service across Essex. NDTScan is the UK's specialist in identifying it, assessing it and telling an owner plainly what to do next.
The Department for Education's list of education settings with confirmed RAAC, published in February 2024, includes 62 settings in Essex, among them Cann Hall Primary School, Elm Hall Primary School and Manningtree High School. The Department of Health and Social Care's list of hospital sites with confirmed RAAC includes Broomfield Hospital in Essex. NDTScan cites the published lists as evidence that RAAC is in the Essex building stock, and for no other reason. Education and health estates were counted because government asked for them to be counted. The equivalent stock in Colchester's council, housing, leisure, retail and commercial buildings has not been, and that is where most uninspected RAAC now sits.
The method NDTScan uses in Colchester is the one it uses everywhere: identify first, then assess. Ground penetrating radar reads the plank's internal structure without cutting into it, distinguishing RAAC from the dense precast, hollowcore and timber it is often mistaken for. Every confirmed plank is then inspected for the defects that matter, cracking, deflection, short bearing, water damage, corrosion and earlier repairs, and classified in line with IStructE guidance. The Colchester owner receives a plank-level record, not a general opinion.
One rule applies to every RAAC survey in Colchester. No remediation, propping, strengthening or replacement should be designed until each plank has been identified and its condition recorded. Some of the most expensive RAAC decisions in the UK were taken on roofs that had never been properly surveyed. The survey is the cheapest part of getting the decision right, and NDTScan will say so to every Colchester client.
Scan before you repair. That is the standing advice for every Colchester client, and the reason NDTScan reports what the concrete contains before anyone specifies what to do about it.
Services Available in Colchester
- RAAC Identification Survey GPR based, plank by plank identification of reinforced autoclaved aerated concrete in roofs, floors and walls across Colchester. Confirms what the element is made of without opening it up, and records plank widths, reinforcement and bearing details as evidence.
- RAAC Condition Assessment Plank level inspection of confirmed RAAC for cracking, deflection, bearing length, water ingress, corrosion and previous repairs, classified in line with IStructE guidance. Reported so a Essex engineer or estates team can act on it directly.
- RAAC Management and Reinspection Monitoring regimes, reinspection intervals and management plans for RAAC that is being kept in service, plus expert input where a Colchester owner needs an independent second opinion on a survey or a remediation proposal.
RAAC in and around Colchester
Typical Colchester instructions: RAAC identification in schools, halls, clinics and council buildings built between 1955 and 1995; plank by plank condition assessment of confirmed RAAC roofs and floors; risk classification in line with IStructE guidance to support decisions on closure, propping or continued use; reinspection and monitoring of managed RAAC; and independent review of surveys and remediation proposals for Essex owners and their insurers. NDTScan covers Colchester from Oxford in the same way it covers the rest of England.
NDTScan also provides RAAC surveys in Southend-on-Sea, Basildon, Chelmsford, Harlow, Brentwood and Clacton-on-Sea and the rest of Essex. The rest of the region is covered from the East of England RAAC surveys page, and the service itself is described on the RAAC surveys page.
About NDTScan
NDTScan is a specialist non-destructive testing company based in Oxford and led by Neil Smuts, author of The RAAC Book. It is the UK's specialist in the identification and analysis of reinforced autoclaved aerated concrete, and a Level 4 UKCSS Operator, the first in the UK to achieve that certification. RAAC surveys in Colchester sit alongside the company's concrete scanning and structural condition survey work, and every report is written to a standard suitable for engineering acceptance, insurers and dispute work.