Retrofitting Fire Doors in Existing Buildings

Upgrading fire safety in existing buildings often starts with fire doors. While new buildings are designed with fire doors from the outset, retrofitting fire doors in existing buildings requires a careful approach to ensure safety, legal compliance and structural compatibility.

Whether you manage a commercial building, mixed-use premises or residential property subject to fire safety legislation — including offices, warehouses, schools, care homes and HMOs — this guide explains what retrofitting involves, when it’s necessary, and how to approach it in line with UK fire safety legislation and guidance such as Approved Document B and the Regulatory Reform (Fire Safety) Order 2005.

What Does “Retrofitting” Mean?

“Retrofitting” fire doors refers to the process of adding or upgrading fire doors in an existing building where they either do not currently exist, or where existing doors do not meet required performance standards.

This can include:

• Replacing non-fire doors with certified fire-resisting doors
• Upgrading existing doorsets (door leaf, frame, seals, ironmongery) to meet fire resistance ratings
• Installing new fire door hardware (closers, intumescent strips, smoke seals)
• Adjusting surrounding structure to support compliant fire door performance

It is often part of a broader fire safety improvement or remedial programme following a Fire Risk Assessment.

When Is Retrofitting Fire Doors Required?

There is no automatic requirement to upgrade every door in an existing building to modern fire door standards. However, retrofitting may become necessary where doors are ineffective or where building work triggers current regulatory requirements.

Retrofitting is typically required in the following situations:

Following a Fire Risk Assessment

Under the Regulatory Reform (Fire Safety) Order 2005, the Responsible Person must ensure that fire precautions (including doors) are effective and maintained. If a Fire Risk Assessment identifies doors that do not perform, an upgrade is usually necessary.

Change of Use, Refurbishment or Material Alterations

Under the Building Regulations 2010 (as amended), material alterations, material changes of use or major refurbishment works can trigger a requirement for new fire door installations or upgrades to comply with current standards.

Where building work affects compartmentation or means of escape, the new work must meet the relevant requirements of Approved Document B. In practice, this can mean that doors within the altered area need to achieve current fire-resistance standards, even if the wider building is older.

Non-compliant Performance

If a door:

• Does not have a suitable fire rating
• Has a damaged frame, seals or hardware
• Cannot self-close or latch properly – then retrofitting or replacement is required to maintain compartmentation and protected escape routes.

Regulatory Framework

Fire Safety Law (Existing Buildings)

For existing commercial buildings, the Regulatory Reform (Fire Safety) Order 2005 provides the overarching legal duty to maintain fire precautions, including fire doors.

Responsible Persons must ensure doors perform, are inspected and maintained, and are suitable for the risk.

Building Regulations and Approved Document B

While Building Regulations and Approved Document B (Volume 2 — buildings other than dwellings) technically apply to new buildings and material alterations, they are routinely used as guidance for best practice in retrofitting fire doors.

This means that, where doors are added or modified, they should comply with the standards and location expectations in Approved Document B.

Standards and Certification

Fire doors should be tested and certified to recognised standards (e.g., BS EN 1634-1), and installed as complete doorsets to ensure performance.

Can You Upgrade an Existing Door to a Fire Door?

Technically yes — but with caveats.

Simply modifying an existing door leaf (e.g., applying intumescent strips or fire mastic) is rarely enough to achieve full fire-resisting performance unless the entire doorset is tested and certified.

In practice:

• Replacing the existing door leaf and frame with a certified fire doorset is the most reliable way to retrofit.
• Adding fire seals and certified hardware is sometimes used when the original frame is suitable and certified testing supports it.
• Attempts to retrofit fire resistance by piecemeal modifications without certification are not robust evidence of compliance.

If you are unsure whether upgrading is viable or full replacement is required, a professional fire door inspection can provide clarity and documented evidence.

Most retrofit scenarios in commercial buildings involve upgrading to FD30 (30-minute fire resistance) or FD60 (60-minute fire resistance) doors, depending on the building’s fire strategy and compartmentation requirements.

Considerations When Retrofitting Fire Doors

Structural Compatibility

Existing frames and openings may not be sized or constructed to accept modern doorsets. Careful assessment and structural adaptation may be required.

Aesthetic and Heritage Constraints

In historic or listed buildings, sensitive design and planning permissions may be needed. Specialist retrofit solutions may be negotiated to maintain character while improving safety.

Seals, Ironmongery and Certification

A fire door is a system — not just a door leaf. It includes:

• Frame
• Intumescent strips
• Smoke seals
• Certified door closers
• Appropriate ironmongery

All components must be compliant to ensure the entire assembly performs.

Correct installation also includes ensuring perimeter gaps are within acceptable tolerances (typically around 3–4mm at the sides and head, subject to manufacturer guidance), and that thresholds are suitable for smoke control where required.

Safety & Testing Evidence

Where existing doors are retrofitted to fire performance, documentation and evidence are key for compliance records. Certification should be kept with the fire safety file.

Practical Steps for Retrofitting Fire Doors

1. Assess current doors in a fire risk assessment — record non-compliances.
2. Determine compliance outcome — door replacement vs retrofit hardware upgrade.
3. Specify certified doorsets and hardware — ensure FD rating meets risk strategy.
4. Plan installation carefully — including frames, seals, closers, ironmongery.
5. Document all work — keep certificates and installation records.
6. Inspect post-installation — verify self-closing function and sealing.
7. Include in ongoing maintenance regime.
8. Schedule ongoing inspections in accordance with risk profile and best practice guidance (often six-monthly in commercial settings).

Common Misconceptions

• “I can just retrofit intumescent strips and it becomes a fire door.”: Simply adding strips does not make a door certified fire resisting — the whole doorset must be tested.
• “Building Regulations don’t apply to my existing building.”: While core Building Regulations are not retrospective, changes, refurbishments and retrofits are treated as new work in part and should comply with current guidance.

Retrofitting Fire Doors in Different Types of Premises

Retrofitting requirements vary depending on building type and occupancy risk.

• In offices and commercial units, upgrades commonly focus on protected corridors and stairwells.
• In warehouses and industrial premises, compartmentation between warehouse and office areas is often critical.
• In care homes and healthcare settings, reliable self-closing performance is essential to support progressive evacuation strategies.
• In schools, high footfall increases wear and inspection frequency requirements.
• In HMOs and mixed-use buildings, separation between commercial and residential areas is particularly important.

Professional Fire Door Installation, Inspection and Maintenance

Retrofitting fire doors in existing buildings requires more than simply replacing a door leaf. Correct specification, certified products and compliant installation are essential to ensure performance and defensible compliance.

At Fire Risk Assessment Network, we support clients across the UK with:

• Fire door installation in accordance with current standards and best practice
• Fire door inspections and surveys to identify non-compliance
• Fire door maintenance advice and ongoing compliance support
• Fire compartmentation surveys where broader passive fire protection issues are identified
• Fire risk assessments to determine whether retrofitting or upgrading is required

Where existing doors are found to be ineffective or uncertified, we can advise on proportionate upgrade strategies, full replacement where necessary, and documented inspection regimes to support legal compliance.

Conclusion

Retrofitting fire doors in existing buildings is not a simple patch-up job — it’s a compliance-driven upgrade that must be planned, specified and installed with care.

Whether you manage a warehouse, office, school, care home or HMO, ensuring fire doors perform correctly can make the difference between safe escape in a fire and uncontrolled spread of smoke and flames.

A fire risk assessment and competent installer are key to getting it right — and documenting your decisions will help demonstrate compliance to enforcers or insurers.

Frequently Asked Questions

Is Retrofitting Fire Doors Mandatory?

Retrofitting fire doors is not automatically required in every existing building. However, if a fire risk assessment identifies that doors are ineffective, or if refurbishment, material alterations or change of use trigger Building Regulations requirements, upgrading may be necessary to maintain legal compliance and life safety.

What Does Retrofitting Fire Doors Mean?

Retrofitting fire doors means installing new fire-resisting doors or upgrading existing door assemblies in an existing building so they meet required fire performance standards. This may involve replacing non-fire doors, installing certified doorsets, or upgrading frames, seals and hardware where appropriate.

When Do Existing Buildings Need Fire Door Upgrades?

Existing buildings may require fire door upgrades following a fire risk assessment, during refurbishment or change of use, or where existing doors are found to be ineffective. While fire safety law is not fully retrospective, doors must be suitable for the level of risk and capable of protecting escape routes and compartmentation.

Can You Upgrade an Existing Door to Make It a Fire Door?

In some cases, existing doors can be upgraded, but only if the door, frame and hardware together can achieve certified fire-resisting performance. Simply adding intumescent strips or fire-rated hinges does not automatically make a door compliant. In many cases, full replacement with a certified fire doorset is the most reliable solution.

Do Building Regulations Apply When Retrofitting Fire Doors?

Building Regulations primarily apply to new work and material alterations. However, when retrofitting or replacing fire doors as part of refurbishment, change of use or structural alterations, the new work should comply with current standards and Approved Document B guidance.

Are Fire Doors Required in All Existing Commercial Buildings?

Not necessarily in every location. Fire doors are required where they are needed to protect escape routes, maintain compartmentation or separate higher-risk areas. The requirement depends on the building’s layout, use and fire strategy.

What Evidence Is Needed After Retrofitting Fire Doors?

Where fire doors are replaced or upgraded, documentation should be retained to demonstrate compliance. This may include product certification, installation records and inspection reports. Maintaining records supports ongoing fire safety management and demonstrates due diligence.