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External wall remediation

Remediation is now the largest body of work in UK fire engineering and about 63% of the Building Safety Regulator's higher-risk caseload. This is what the process looks like, what the appraisal actually has to establish, and where projects go wrong.

PAS 9980:2022BR 187Building Safety Act 2022Approved Document B
5,000+
Residential buildings 11 m+ in England identified with unsafe cladding
63%
Share of the BSR higher-risk caseload that is remediation work
35 wks
Median Gateway 2 determination for remediation, against 22 weeks for new build

Building Safety Regulator published application data to 28 June 2026, and government remediation programme data. Figures are dated; check the current release before quoting them.

Where remediation stands in 2026

Nine years after Grenfell, external wall remediation is the largest single body of work in UK fire engineering. Around 5,000 residential buildings of 11 m and above in England have been identified with unsafe cladding, and a substantial number of those have not started work.

It is also now the dominant workload at the Building Safety Regulator: remediation work accounts for roughly 63% of the higher-risk building caseload, and remediation applications take a median of about 35 weeks to determine against about 22 weeks for new build.

For a fire engineer the practical consequence is that remediation is not a niche any more. It is the work, and it has a different shape to new build: the building already exists, the information about it is incomplete, and every assumption has to be evidenced rather than specified.

The route through a remediation project

  1. Establish what is there. Desktop review of whatever records exist, then intrusive opening-up. On most buildings the records are wrong, and the opening-up is what the assessment actually rests on.
  2. Fire risk appraisal of external wall construction (FRAEW). Carried out to PAS 9980:2022, producing a risk rating and, where the rating is not low, a set of recommendations.
  3. Decide the remediation strategy. Full replacement, partial replacement, or mitigation. This is an engineering and commercial judgement, and it is where the fire engineer earns their fee.
  4. Design and consent. If the building is higher-risk, the works go through Gateway 2 as building control approval before work starts.
  5. Construction, change control and handover. With the golden thread updated to reflect what was actually installed, not what was drawn.

The most expensive mistake on a remediation project. Treating the FRAEW as a compliance document rather than a design input. An appraisal that says "medium risk, replace the cladding" without establishing the cavity barrier condition, the compartmentation behind the wall and the state of the fire stopping produces a scope that grows the moment the scaffold goes up.

PAS 9980 and what replaced EWS1

PAS 9980:2022 is the code of practice for appraising the fire risk of external wall construction on existing multi-storey residential buildings. It is a methodology, not a pass/fail test; the output is a risk rating with reasoning behind it, produced by a competent person who is prepared to put their name to the judgement.

The EWS1 form is a lending instrument, not a standard. It was designed to give valuers something to work with, and it is increasingly issued on the back of a PAS 9980 appraisal rather than instead of one. Where the two conflict, the appraisal is the engineering document.

Our PAS 9980 triage tool gives an indicative view of which factors are likely to drive the rating on a given building, and the full guide explains the process.

The funding and enforcement landscape

  • Developer remediation contracts. Developers have committed to remediate buildings they developed, at their own cost.
  • The Building Safety Fund and the Cladding Safety Scheme. Public funding routes for buildings without a solvent developer, with eligibility criteria that shape which surveys and appraisals are needed and when.
  • Remediation Acceleration Plan targets. Government has set dates by which buildings in the funding schemes must have started or completed. That is what is driving the current volume of appraisal work.
  • Enforcement. Where nothing is happening, regulators and local authorities have powers under the Building Safety Act and the Housing Act. Remediation orders and remediation contribution orders are being made.

The engineering issues that recur

  • Cavity barriers. Missing, wrong product, wrong orientation, or defeated by the way the rail system was installed. The most common finding on opening up.
  • Combustible insulation behind a non-combustible skin. The rainscreen passes; what is behind it does not.
  • Balconies. Combustible decking, soffits and dividers create a vertical spread route that has nothing to do with the wall build-up.
  • Spandrel and window interfaces. Where the wall meets the opening is where compartmentation is most often lost.
  • Compartmentation behind the wall. The external wall assessment repeatedly turns into an internal compartmentation survey, and the scope has to allow for it.
  • Space separation after recladding. Adding a combustible external surface can change the unprotected area calculation on a building that previously complied; see BR 187.

Interim measures and evacuation strategy

Between identifying a defect and completing the works there is usually a period of years. That gap is managed with interim measures: waking watch, common alarm systems, or a change of evacuation strategy from stay-put to simultaneous evacuation.

Moving a building off stay-put is a significant decision with a significant cost, and it changes the escape design assumptions completely; stair capacity that was never intended to take the whole building at once suddenly has to. It is worth calculating rather than assuming; the escape and stair width calculator will tell you quickly whether the existing stair can do it.

Guides on remediation and external walls

Calculators for external wall work

Questions people ask

What is a FRAEW?

A fire risk appraisal of external wall construction, carried out to PAS 9980:2022. It establishes what the external wall is actually built of, assesses the risk of fire spread over or within it, and gives a risk rating with reasoning. It is a competent person's judgement, not a pass/fail test.

Has PAS 9980 replaced EWS1?

They do different things. PAS 9980 is the engineering methodology for appraising an external wall. EWS1 is a form used by lenders and valuers. An EWS1 is increasingly issued on the back of a PAS 9980 appraisal rather than instead of one, and where they conflict the appraisal is the engineering document.

Does external wall remediation need Gateway 2 approval?

If the building is a higher-risk building, at least 18 m or seven storeys with two or more residential units, then building work on it requires building control approval from the Building Safety Regulator, which is the Gateway 2 process. Remediation currently makes up the majority of that caseload.

Why do remediation applications take longer than new build?

Existing buildings come with incomplete information, which means more requests for information during determination. Published data shows a median of about 35 weeks for remediation against about 22 weeks for new build higher-risk buildings.

What is a waking watch and when is it needed?

An interim measure where staff patrol a building to raise the alarm, used where a defect means the existing evacuation strategy cannot be relied on. It is expensive and is normally replaced as quickly as possible by a common alarm system, which is cheaper to run and more reliable.

Remediation strategies, drafted and checked

Remediation reports have to justify every conclusion from evidence that is usually incomplete. FireStrategy.ai drafts the strategy, checks it against PAS 9980 and the Approved Documents, and flags every claim that is not supported by something in the file.