Fire Strategy for Existing Buildings

Why Existing Buildings Need a Fire Strategy

Your building is occupied. It has no fire strategy. Here is what that means and what to do about it.

Many existing buildings were constructed before fire strategies became a standard requirement, or were built under a planning or building control process where the fire strategy was never formally produced or retained. Others have strategies that are 20 years old, no longer reflect the building as extended or altered, or simply cannot be located.

An existing building without a current fire strategy faces a specific set of problems: building control cannot sign off refurbishment works, lenders and purchasers are increasingly requiring evidence of fire safety compliance, and under the Building Safety Act 2022, accountable persons for higher-risk buildings must register with the Building Safety Regulator and submit a building safety case — which requires a documented fire strategy as its foundation.

We produce fire strategy reports for existing buildings that are assessed against the standards in force at the time of original construction. Where a building has been altered or extended at different points in time, each phase is assessed against the applicable code of that period. The result is a single coherent document that captures the fire safety provisions as they actually exist in the building today.

When Is It Required?

Five situations that require a retrospective fire strategy

Retrospective fire strategies arise at different points in a building's lifecycle, often triggered by regulatory change or transaction activity.

BSR registration for higher-risk buildingsBuildings of at least 18 metres or seven storeys with two or more residential dwellings must be registered with the BSR. A retrospective fire strategy is typically required as part of this submission.

Building safety case preparationThe building safety case report must demonstrate a building is safe to occupy. A retrospective fire strategy is the core document underpinning that case for buildings without a current strategy.

Fire safety review or auditWhere a fire safety review identifies that no fire strategy exists, or that the existing one is materially incomplete or out of date, a retrospective strategy is required.

Refurbishment or change of useAny significant refurbishment or change of use will require an updated fire strategy. If no baseline strategy exists, a retrospective document must be produced first.

Property transaction or leasehold disputePurchasers, lenders, and leaseholders increasingly require evidence of the fire safety design rationale as part of due diligence on existing buildings.

What does a retrospective fire strategy include?

A retrospective fire strategy documents the fire safety provisions as they exist in the building today, assessed against the standards in force at the time of original construction. The report covers every element that would be expected in a contemporary fire strategy, adapted to reflect the age, use, and condition of the existing structure.

The document typically addresses: means of escape and evacuation routes; compartmentation and fire separation; structural fire resistance; passive and active fire protection systems; fire detection and alarm arrangements; firefighting access and facilities; and any departures from the applicable codes of the period. Where the building has been altered or extended since original construction, each phase is assessed in the context of the regulations that applied at that time.

For higher-risk buildings subject to the Building Safety Act 2022, the retrospective fire strategy forms the fire safety component of the building safety case. It provides the accountable person with the documented fire safety rationale required for registration with the Building Safety Regulator (BSR) and ongoing compliance.

Standards assessed against

Approved Document B (version in force at time of construction)

Earlier editions, BS 5588 series, and period codes referenced where applicable

Current guidance

BS 9991:2015 / BS 9999:2017

Referenced where improvements or deficiencies are identified against current best practice

Building Safety Act output

Foundation document for BSR registration and building safety case

Accepted by the Building Safety Regulator for higher-risk building submissions

Understanding the difference

Retrospective fire strategy vs new-build fire strategy

The two documents serve the same purpose but follow different assessment frameworks.

Retrospective: as-built assessment Documents fire safety provisions as they exist today. Assessed against the standards applicable at the time of original construction, not current Approved Document B. Departures from current guidance are noted but assessed in their historical context.

New-build: design-stage document Produced during RIBA Stage 2 or 3 to establish the fire safety design strategy for a proposed building. Assessed against current Approved Document B, BS 9991 or BS 9999. Evolves through construction and is finalised on completion.

Retrospective: records review required Requires access to as-built drawings, construction records, and where available, any original fire strategy documentation. Where records are incomplete, a site survey is used to establish the as-built condition. Incomplete records do not prevent the strategy from being produced.

Typical programme: 7 to 14 working days Most retrospective fire strategies are delivered within 7 to 14 working days from receipt of drawings and site access. Complex buildings, or those requiring phased assessments covering multiple construction periods, may require a longer programme.

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Common Questions

Frequently asked questions

My building has never had a fire strategy. Where do I start?

Start by contacting a chartered fire engineer. We will ask for whatever drawings and records you have — even partial information is useful — and advise on whether a site survey is needed to fill the gaps. We then produce a fire strategy that documents the building as it stands, assessed against the standards applicable at the time of construction. The whole process typically takes 7 to 14 working days from instruction.

Does my existing building need to meet current fire safety standards?

Not necessarily. A fire strategy for an existing building is assessed primarily against the standards in force at the time of original construction — which may be an earlier edition of Approved Document B, BS 5588, or another period code. Current standards are referenced where there are identified deficiencies or where the building presents a specific risk, but the assessment is proportionate to the building's age and condition. The goal is to document what the building has, not to require it to be rebuilt to current standards.

Can I sell or refinance a building if it has no fire strategy?

Increasingly, no. Lenders, purchasers, and solicitors are routinely requesting fire strategy reports as part of due diligence on residential and commercial properties, particularly where there has been any refurbishment or change of use. For higher-risk buildings, the absence of a fire strategy will prevent registration with the Building Safety Regulator, which is a legal requirement under the Building Safety Act 2022. Obtaining a fire strategy report before a transaction avoids delays and removes a significant buyer objection.

My building has been extended or altered several times. How is that handled?

Each phase of the building is assessed against the regulations that applied when that phase was constructed or altered. The fire strategy maps the building as a whole and identifies where different standards apply to different parts of the structure. This is standard practice for existing buildings with complex construction histories, and our engineers are experienced in navigating multi-phase assessments. We advise on any interface issues between phases where the fire safety provisions interact.

I cannot find the original drawings. Can you still produce a fire strategy?

Yes. Where drawings or construction records are unavailable or incomplete, we conduct a site survey to record the as-built condition of the building, including compartmentation, means of escape routes, fire protection systems, and structural fire resistance. This is a common situation with older buildings and does not prevent the fire strategy from being produced. We advise on what is needed before work begins so there are no surprises.

How much does a fire strategy for an existing building cost?

Fees depend on the size and complexity of the building, the extent of existing records, and whether a site survey is required. We provide a fixed-fee proposal within 1 to 2 working days of receiving basic project information. There are no hourly rates or unexpected additions: the fee quoted at the outset is the fee charged.

Who needs to commission a fire strategy for an existing building?

Typically the building owner, freeholder, or accountable person under the Building Safety Act. In a transaction context, it may be commissioned by the vendor's solicitors to resolve a due diligence query, or by a purchaser's team as a condition of financing. For buildings undergoing refurbishment, the client or principal contractor may commission the strategy to satisfy building control. We work directly with all of these parties and are familiar with the requirements of each context.

Is a fire strategy for an existing building accepted by building control?

Yes. Fire Safety Services is a chartered independent practice, and our fire strategies are accepted by local authority building control, approved inspectors, the Building Safety Regulator, and responsible persons under the Regulatory Reform (Fire Safety) Order 2005. All reports are produced by chartered engineers with IFE membership and carry the authority of an independent professional assessment.

Fire Safety Services

Fire Engineering & Safety

Fire Safety Services is a chartered independent fire engineering and safety consultancy. We deliver fire strategy reports, building safety cases, EWS assessments, planning fire statements, and specialist consultancy across London and the UK. Advisory-only, conflict-free advice from engineers with over 30 years of collective experience.

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