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RAAC Surveys for Schools and Public Buildings

Reinforced autoclaved aerated concrete was used across public buildings from the 1950s to the mid 1990s. Finding it is the first problem. Grading it honestly is the second.

What we cover.

RAAC planks were used widely in schools, hospitals, libraries and other public buildings, and much of the stock is now past the design life originally assumed. The work divides into three stages that get conflated: establishing whether RAAC is present at all, grading the condition of what is there, and deciding what to do about it. Each needs different access and produces a different kind of answer, and an estate-wide programme that treats them as one exercise produces numbers nobody can act on.

Identification surveys to establish whether RAAC is present
Condition grading of identified RAAC planks
Structural assessment of bearing, deflection and reinforcement condition
Prioritisation across an estate rather than building by building
Propping and temporary support design where grading requires it
Remediation and replacement options appraised
Monitoring and management regimes where removal is not immediate
Reporting written for estates teams and their governing bodies

In detail

What raac surveys for schools and public buildings actually involves.

Identification

Identification is harder than it sounds because RAAC is usually concealed above a ceiling and is easily confused with other lightweight units. Getting it wrong in either direction is expensive: a false positive closes a building that did not need closing, and a false negative leaves a risk in place with a document saying it is not there.

Grading

Grading is where the engineering judgement sits, and it depends on bearing length, deflection, cracking pattern, reinforcement condition and evidence of water ingress rather than on age alone.

Propping buys time

Where grading requires intervention, propping is a holding measure and not an answer, so the report sets out what the holding measure buys in time and what has to follow it.

How Lead Group helps

We survey to establish whether RAAC is present and, where it is, grade it on bearing, deflection, cracking and water ingress rather than on age. The report is written for the people who have to act on it: what is safe now, what needs propping, what needs replacing, and in what order.

How we work

How do you tell whether a building contains RAAC?

By survey, not by age or record drawings. RAAC is usually concealed above ceilings and is readily confused with other lightweight concrete units, so identification means physical access to the soffit and inspection of the plank profile, bearing and reinforcement arrangement. Age narrows the search, because most RAAC dates from the 1950s to the mid 1990s, but it does not answer the question either way. Both false positives and false negatives are costly, so the survey has to be conclusive rather than indicative.

Identification, grading and assessment kept as separate questions
Grading based on bearing, deflection and reinforcement condition
Estate-wide prioritisation rather than building by building
Propping treated as a holding measure with a stated end point
Professional indemnity insured

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 surveys for schools and public buildings.

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.

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Questions

Common questions

Which buildings are most likely to contain RAAC?

Public buildings constructed between the mid 1950s and the mid 1990s, particularly schools, hospitals, libraries and offices built with flat or shallow-pitched roofs. Age narrows the search but does not settle it, because RAAC was one of several lightweight options and its use was not uniform. Only a survey answers the question for a specific building.

What do the RAAC condition grades mean?

Grading places identified planks into bands reflecting how much risk their present condition represents, based on bearing length, deflection, cracking, reinforcement condition and water ingress. The grade drives the response: routine management at one end, immediate propping or closure at the other. The important point is that grading is an engineering judgement made against evidence, not a category read off the age of the building.

Is propping a solution?

No, it is a holding measure. Propping buys time by providing an alternative load path while a permanent answer is arranged, and a report that recommends propping should state what it buys and what has to follow it. Propping left indefinitely without a plan becomes a permanent alteration nobody has designed for.

Can you survey a whole estate?

Yes, and across an estate the useful output is prioritisation rather than a stack of individual reports. Identification first, across the buildings where the construction period makes RAAC plausible, then grading where it is found, then a ranked programme. That sequence spends the survey budget where it changes decisions.

Do you design the remediation as well?

Yes. Where RAAC has to be removed or supported permanently, the replacement structure, the temporary works needed to install it and the sequence of doing so in an occupied building are all structural design, and keeping the assessment and the remediation with the same engineer avoids the gap that opens when they are split.

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