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RAAC Inspection & Remediation

Reinforced autoclaved aerated concrete can fail with very little warning, and identifying it is only the first step. We survey, categorise, monitor, prop and design the remediation, from first inspection through to removal.

What we cover.

RAAC was used widely in UK public and commercial buildings from the 1950s to the mid 1990s, most often as roof planks. It behaves differently from ordinary reinforced concrete: the reinforcement bond is weaker, the material is porous, and deterioration is frequently hidden above a ceiling. Managing it is a structural engineering problem, not an inspection exercise.

RAAC identification surveys
Condition assessment and risk categorisation
Structural appraisal of RAAC planks and bearings
Intrusive investigation and opening up
Monitoring and management plans
Temporary propping and support design
Remediation and strengthening design
Removal sequencing and temporary works design

In detail

What raac inspection & remediation actually involves.

Identification first

The first question is whether you actually have RAAC. It is routinely confused with ordinary precast concrete and with other lightweight systems, and a survey that misidentifies it either creates alarm where there is none or misses a genuine risk. Identification means getting above the ceiling and examining the plank itself, its bearing and its reinforcement, not inferring from the building's age.

Grading, not yes or no

Where RAAC is confirmed, the useful output is a risk categorisation rather than a yes or no. Planks vary across a single roof: bearing lengths differ, some have been penetrated by later services, and water ingress concentrates deterioration in specific bays. A survey that grades each area lets an estate be managed on evidence and a programme built by priority, rather than closing a building because one plank looked poor.

Remediation options

Remediation is rarely a single answer. Depending on condition, span and bearing, it can mean propping and monitoring, installing a secondary support system beneath the planks, strengthening the bearings, or full removal and replacement. Removal is the most involved, because taking a structural roof element out means the temporary works have to carry everything above and around it in the meantime.

Where we have done this

Our engineers have led RAAC inspection, survey, reporting and remediation across fire stations, industrial premises and community buildings, including designing the temporary works for panel removal on an occupied site.

How Lead Group helps

We identify whether the material is actually RAAC, grade what is there plank by plank rather than issuing a single verdict for a whole roof, and set out the remediation options with what each one costs in time and disruption. Where propping is the immediate answer, the report says what it buys and what has to follow it.

How we work

How do you know whether a building actually contains RAAC?

By examining the planks directly rather than inferring from construction date. RAAC is regularly confused with ordinary precast units, and the distinction matters because the failure mechanism is completely different. Identification means access above the ceiling, inspection of the plank, its bearing length and its reinforcement condition. Where access is restricted, we say what we could and could not see rather than implying whole-building coverage.

Designs checked and signed by a Chartered Structural Engineer
Risk categorised by area, not a single building-wide verdict
£5m professional indemnity cover
Propping and removal temporary works designed in-house

Not sure what you need?Send us your drawings, or just a photograph of the wall. We will tell you what is required and what it costs before you commit to anything.

Get a quote 020 3432 4186

Standards & codes

The codes behind raac inspection & remediation.

Eurocodes 0-9 & UK National Annexes

BS EN 1990 through BS EN 1999 govern the basis of design, actions, and the design of concrete, steel, timber, masonry and aluminium structures. Every calculation we issue references the relevant Eurocode part and its UK National Annex, and states which parts were applied.

Analysis, design & drafting software

Structural analysis and design in Tekla Tedds and Tekla Structural Designer, with Autodesk Robot, CSC Fastrak, CSC Portal Frame, MasterSeries and Hilti Profis used where a scheme suits them. Drawing production in AutoCAD, and modelling in Autodesk Revit where a project is delivered in BIM. Output is issued as readable calculations rather than raw software printouts, so a checker or a building control officer can follow the reasoning.

Approved Document A (Structure)

The Building Regulations requirement your local authority Building Control checks against. Our calculations and drawings are prepared to demonstrate compliance so your submission is accepted without back-and-forth.

Professional indemnity insured

Every report and calculation package is backed by professional indemnity cover, which is what lets a lender, Building Control or another engineer rely on it.

Scope of an inspection. Inspections are carried out within the scope and limitations set out in the fee proposal and stated in the report. Unless expressly agreed otherwise, an inspection covers what is reasonably accessible at the time and is not a warranty that every defect, deterioration or concealed condition has been identified. Where something cannot be seen, we say so and set out what would establish it.

Process

From enquiry to sign-off.

Enquiry

Send drawings or describe the problem. We confirm the scope, the deliverables and a target timescale.

Information

We agree the survey, drawings or data we need and any site access required.

Engineering

Design, calculation or assessment to the relevant Eurocodes and UK National Annex.

Issue

A clear, defensible report or set of calculations, with assumptions and limitations stated.

Selected work

Real structures, surveyed and engineered.

All work →

Sport and recreationCharlton Athletic FC, The ValleyTwo steel monopitch stand roofs rising to 27 metres were assessed for a proposed solar PV installation. Both were cleared to carry the arrays as they stand, and the fragile roofs were surveyed entirely by drone with nobody working at height.

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Manufacturing and industrialWienerberger, Tamworth

EducationCarlisle College

Film and mediaDragon Studios, Pencoed

Questions

Common questions

Which buildings are most likely to contain RAAC?

Public and commercial buildings constructed between roughly the 1950s and the mid 1990s, most commonly in roof construction. Schools, hospitals, fire stations, community buildings and industrial premises are the usual candidates, but the only reliable answer comes from inspection.

Does finding RAAC mean the building has to close?

Not usually. Condition varies across a roof, and a graded assessment often shows that most areas are serviceable while specific bays need propping or replacement. A blanket closure is sometimes necessary but it should follow evidence rather than precede it.

Can you design the temporary works for removal?

Yes. Removing a structural roof element means everything above and around it has to be carried in the interim, and that propping is a designed system rather than a site decision. We design it alongside the removal sequence.

Can you assess a whole estate rather than one building?

Yes, and reporting in a consistent format across an estate is what allows buildings to be compared and a programme prioritised properly.

What happens if access above the ceiling is limited?

We report what we were able to inspect and what we were not, and we recommend where further access is needed. We do not extrapolate a whole-roof verdict from a handful of accessible bays.

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