Inspecting and Maintaining Fire Barriers in Existing Buildings

A fire barrier in an existing building is rarely judged by how it was first drawn. It is judged by what remains intact after years of access panels, service alterations, tenant churn, water ingress, small repairs, larger refurbishments and the general untidiness of occupation. Passive fire protection ages in silence. When it fails, it usually does so because nobody went back to look. The legal duty is not especially mysterious: under Article 17 of the Regulatory Reform (Fire Safety) Order 2005, where necessary to safeguard relevant persons, fire precautions must be subject to a suitable system of maintenance and maintained in an efficient state, in efficient working order and in good repair. 

That matters because fire barriers are not decorative partitions hidden above ceilings and inside voids. They are part of the building’s compartmentation strategy. Approved Document B requires cavity barriers to divide cavities and close the edges of cavities, and it distinguishes these from fire-stopping details. In existing buildings, that means the original fire-resisting logic can be quietly undone if barriers are removed, breached, badly altered or left unsupported after later works. 

The first discipline in existing buildings is to stop assuming that hidden protection is still there simply because it once was. The Building Safety Regulator’s guidance for higher-risk residential buildings is blunt on this point: dutyholders should try to find and keep records of the relevant safety standards that applied when the building was built and after later refurbishments, and they should be able to prove that safety measures were designed, installed, maintained and inspected by competent people in accordance with legislation, standards and manufacturers’ recommendations. 

That immediately turns inspection into two tasks rather than one. The first is physical verification. The second is evidence recovery.

Physical verification means locating the fire barriers that matter: above suspended ceilings, in roof voids, at wall heads, around risers, within service zones, behind boxing, within façade cavities where relevant, and around penetrations that have been introduced since completion. In many existing buildings, the defects are not subtle. Barriers are interrupted by later cabling, cut back for ductwork, displaced by maintenance access, or left with open edges at awkward junctions. The problem is rarely the idea of the barrier. The problem is continuity. Approved Document B requires cavity barriers to be tightly fitted to rigid construction and mechanically fixed where appropriate, or otherwise fire-stopped; it also requires them to be fixed so their performance is not made ineffective by movement, collapse of services, failure of fixings or failure of the construction to which they abut. 

Evidence recovery is less glamorous but just as important. Existing buildings often carry the scars of multiple contractors and incomplete handovers. The BSR guidance says you should keep records of the original design and construction, the current condition of the building, and the types of refurbishment or other changes that have taken place. It also says that if information is missing, you should keep a record of the steps taken to find it. That is a sensible standard. A barrier you cannot locate, identify or verify is not a managed fire precaution. It is a rumour in the ceiling. 

Inspection should therefore follow the likely routes of failure rather than a neat theoretical checklist. Start with places where compartmentation is most likely to have been disturbed: service penetrations, risers, ceiling voids above escape routes, plant areas, mixed-use interfaces, refurbished tenancy boundaries and roof junctions. Approved Document B requires cavity barriers at edges of cavities, around openings such as windows, doors and service entry points, and at junctions with compartment floors and compartment walls. In an existing building, each of those locations is also a likely point of compromise. 

Service penetrations deserve particular suspicion. The BSR’s guidance for high-rise residential buildings singles out fire stopping and warns that changes and refurbishments, whether by contractors or residents, can compromise it. That is exactly what happens in older stock: a new cable, a replacement pipe, a retrofit access control line, a data upgrade, a new extract route. Each looks minor in isolation. Collectively they can turn a once-sound barrier into a perforated suggestion. 

Maintenance, then, is not a matter of waiting for visible damage. It is a managed process of checking, recording, repairing and re-verifying. Article 17 requires a suitable system of maintenance; the BSR guidance adds that if problems are found and measures are not sufficient, they should be reviewed and amended, and any changes to maintenance regimes should be recorded with the reasons for the changes. That points to a practical regime: inspect after refurbishment, inspect after service alterations, inspect when water damage or impact damage is discovered, inspect periodically in higher-risk areas, and inspect whenever records are incomplete enough to cast doubt on the fire strategy. 

Competence matters throughout. The BSR guidance states that safety measures should be capable of being proved to have been designed, installed, maintained and inspected by competent people, and that building work during refurbishment should be undertaken by people with the necessary skills, knowledge, experience and behaviours. In existing buildings, that means the person opening up, assessing defects, selecting repair details and signing off reinstatement must understand tested systems, substrates, abutments, penetration treatments and the wider compartmentation strategy. This is not maintenance by guesswork. 

There is also a quiet point about proportion. Not every building needs the same level of intrusive inspection, but every building needs enough inspection to justify confidence. The BSR guidance frames reasonable steps as proportionate to the building’s circumstances and risks. A simple, lightly altered building with good records may require less opening up than a heavily refurbished mixed-use block with fragmented documentation and multiple service interventions. The standard is not paranoia. The standard is evidence. 

What good maintenance looks like is almost disappointingly plain. Barriers are identified on plans and in reality. Access is arranged before defects become emergencies. Penetrations are minimised and properly sealed. Unsupported edges, damaged boards, missing sections and poorly reinstated openings are repaired using appropriate tested or assessed details. Changes are recorded. The fire strategy is checked after refurbishment, not assumed to have survived it. In higher-risk residential buildings, accountable persons are expected to keep and update information on prevention and protective measures, including original design information, the current condition of the building and the changes that have taken place. That is the right discipline more broadly, not just for one category of building. 

The essential truth is rather unfashionable. Fire barriers in existing buildings do not usually fail because the science was unsound. They fail because buildings change and nobody maintains the invisible work with the seriousness it deserves. Fire protection is often lost one hole, one omitted repair and one undocumented alteration at a time.

Inspection restores honesty. Maintenance restores continuity. And in existing buildings, continuity is the difference between compartmentation as designed and compartmentation as fiction.

FIRE BARRIERS MANUAL