Our experienced team provides comprehensive fire barrier services to protect your property and its occupants. From fire barrier installations to inspections and repairs, trust us to enhance fire resistance and create a secure environment. Your peace of mind is our mission.
Cavity barriers are the part of the external wall that most often decides whether a building passes or fails. Specified correctly on the drawings, they’re then installed inside the wall build-up – and once the cladding and finishes go on, nobody can see whether they’re right, wrong or missing. That’s why they’re the most common finding in external wall fire reviews, and why they’re Gateway-critical on any higher-risk residential new build.
Ark installs and remediates cavity and external fire barriers at building scale – for Tier 1 contractors on new-build residential, and for landlords, developers and Build-to-Rent operators working through PAS 9980 remediation. We survey what’s actually in the wall, install to the tested system, own the interface with the facade package rather than assuming someone else has it, and document every barrier so the external wall can be evidenced, not just hoped over.
A cavity barrier is a classic golden-thread failure point. It’s specified on the drawings, but installed out of sight – and defects only surface at an intrusive survey or, worse, in a fire. Three things go wrong again and again: the wrong product for the cavity, barriers left unsealed where services penetrate them, and barriers omitted entirely at the interface with the facade. That last one matters most, because on many projects the barriers are fitted by the facade contractor but any failure comes back to passive fire.
Ark treats the barrier scope as something to own, not assume. We survey the wall build-up to record what’s genuinely there, coordinate the barrier line with the facade package in writing, and evidence every barrier back to its test data – so the external wall system can be demonstrated as a complete, continuous line of defence rather than a set of components that may or may not meet in the cavity.
If the barrier can’t be evidenced
FRAEW assessors and Building Safety Regulator reviewers work to a hard rule: no evidence is treated as no barrier. For a landlord mid-remediation, a missing evidence record can mean re-opening a wall that was already closed up – double the cost and double the resident disruption. For a Tier 1 on a new build, it’s a Gateway delay on a scheme that can’t complete or occupy until it clears.
If the install isn’t controlled
Barriers get fitted with the wrong product for the cavity, left unsealed where services pass through, or omitted at the facade interface where responsibilities blur. Once the cladding is on, none of it is visible – the defect stays hidden until the next intrusive survey or an actual fire. And not every product is tested in every configuration, so a barrier that looks installed may not perform in that specific wall.
How Ark handles it
An intrusive survey methodology that records what’s actually in the wall, photographic evidence of every barrier installed, product traceability back to the test data for that configuration, and documented coordination with the facade contractor so the barrier scope is owned rather than assumed. The external wall gets an evidence trail that stands up to a FRAEW, an EWS1 review or a Gateway submission.
Cavity and external fire barriers are specified at building scale, which is where Ark works – larger packages where the barrier line runs across a whole facade, roof void or atrium:
Whether the barrier is installed by us or reinstated after a facade review, the scope is owned end-to-end – surveyed, installed to the tested system, coordinated with the facade package, and documented.
External fire barriers are large-scale fire-resistant systems installed across open voids in a building’s structure – typically roof voids, ceiling voids, and atrium voids up to 10.5 metres deep. They’re used where the void is too big for a standard cavity barrier and there’s no solid wall or floor to maintain compartmentation. Vertical external fire barriers can provide up to 120 minutes of insulation and integrity; friction-fit slab barriers provide up to 60 minutes.
Cavity fire barriers are smaller fire-resistant products installed inside the narrow cavities within a building’s fabric – external wall cavities, party wall cavities, and floor cavities. Under Approved Document B, they must provide at least 15 minutes of fire integrity and 30 minutes of structural stability. On residential buildings over 18 metres, the Building Safety Act 2022 places stricter requirements on cavity barrier specification, installation, and documentation.
We provide our fire barrier system services throughout the UK but have offices in the following locations.
Get in touch with our team for assistance on your next fire barrier project.
When it comes to Passive Fire Protection, you need a company that you can rely on. Ark Fire Protection is proud to be accredited by the leading industry bodies – ensuring that we always meet the highest standards of quality and safety, and that our customers can always expect a first-class service.
We’re also ISO 9001 certified, meaning that our quality management systems are regularly audited and approved. So when you choose Ark Fire Protection, you can be confident that you’re making the best possible decision for your property.
At Ark Fire Protection all fire barrier services are third party accredited by FIRAS scheme, Health & Safety accredited and ISO 9001 quality assured.
Barriers are hidden the moment the cladding and finishes go on, which is exactly why the record matters. In Onetrace, every barrier is logged as it’s installed – product and batch, the tested configuration it matches, location in the wall or void, photograph and sign-off – before it’s covered up. The result is a golden-thread record the Accountable Person, the FRAEW assessor or the Building Safety Regulator can rely on, proving the external wall is continuous even though none of it can be seen.
When it comes to passive fire protection, and keeping your premises and its occupants safe – it is absolutely essential that the fire barrier system is installed correctly, and by a professional. A trusted fire barrier installation team will ensure all regulations and codes are adhered to, and provide complete peace of mind that your property is protected against the risk of fire.
At Ark Fire Protection, we have years of experience in fire barrier installation, and are dedicated to delivering the very best service possible. We employ highly trained and certified professionals who can provide a comprehensive installation process from start to finish, from consultation and design to installation and inspection. At we installed Corofil Cavity Barriers and Slab Edge systems across a live operational building to satisfy its complete fire safety strategy.
Passive fire protection installation services in the United Kingdom are provided by us to a wide range of clients, ensuring that your structures are safe, secure, and abide by building and fire safety standards (Approved Document B).
Fire is a hazard for commercial and industrial sites that can result in service interruptions or, worse, loss of life. Whether you’re developing new housing or working on new or old health, education, leisure, retail, business, or industrial premises, Fire Barrier Services can help individuals remain safe.
Ark Fire Protection can provide the expert and reliable fire barrier services to keep your premises safe from the spread of fire.
At Ark Fire Protection Services, we only use industry leading fire barrier products from brands such as Rockwool and FireFly.
These products have been rigorously tested to ensure that they meet the highest standards of quality and performance, and we’re proud to offer them to our clients. We believe that using the best products is essential to providing the best possible service, and we’re always looking for ways to improve the quality of our services.
To meet fire safety regulations, cavity barriers are essential in buildings. The regulations mandate that cavity barriers must offer at least 15 minutes of fire resistance and maintain their structural integrity for 30 minutes. Regulations require that buildings should be built with consideration for how fires can spread through compartments in floors, walls, and ceilings. The installation of cavity barriers vertically and horizontally will meet this requirement. For external wall systems on residential buildings over 11 metres, the following additional requirements apply: • Building Safety Act 2022 – Introduces stricter controls on cavity barriers in external wall systems, including duties on the Accountable Person to maintain a “golden thread” of information covering specification, installation, and ongoing inspection. • BS 8414 – The British Standard test method for the fire performance of external cladding systems, including the cavity barriers within them. Systems must be tested as a complete build-up, not as individual components.
Cavity fire barriers are installed in various locations within a building to prevent the spread of fire and smoke through concealed spaces. We install fire barriers in the following areas:
Fire cavity barriers play a critical role in maintaining the fire safety of a building. Their primary function is to compartmentalise a structure by creating barriers within concealed spaces, which effectively slows down the spread of fire and smoke. This containment allows occupants more time to evacuate safely and provides emergency services with a greater window to control and extinguish the fire. By preventing the rapid movement of fire through unseen voids and cavities, fire barriers help to minimise potential damage to the building and protect the structural integrity.
Fire barriers play a critical role in a building’s overall fire strategy by protecting concealed spaces that aren’t visible during normal occupation. While walls, floors, and fire doors form primary compartments, fire barriers ensure that fire and smoke cannot bypass these protections through cavities, voids, and service routes.
In modern buildings, services, lightweight construction methods, and complex roof and ceiling voids create hidden pathways where fire can spread rapidly if not correctly protected. Fire barriers restore compartmentation at these vulnerable points, helping maintain the integrity of fire compartments, protect escape routes, and slow fire spread long enough for safe evacuation and emergency response.
Fire barriers work in conjunction with other passive fire protection measures such as fire stopping, fire doors, partitions, and fire curtains. Together, these systems form a continuous line of defence that supports compliance with Building Regulations Approved Document B and the assumptions set out in the building’s fire risk assessment and fire strategy.
Fire barriers must be tested, specified, and installed in line with recognised standards to ensure they perform correctly in a real fire scenario. In the UK, performance is demonstrated through fire resistance testing rather than visual inspection alone.
BS 476 fire resistance testing assesses how long a fire barrier can maintain integrity when exposed to fire. This testing confirms that the barrier can resist flame and hot gases for a defined period, helping to limit fire spread within cavities and concealed spaces. The EN 1366 series of standards applies specifically to fire resistance testing of service penetrations, linear joints, and cavity barrier systems. These tests replicate real installation conditions, ensuring barriers perform as part of a complete system rather than as individual components.
Correct certification is equally important. Fire barriers must be installed exactly as tested, including fixings, orientation, compression, and continuity. Deviations from tested systems can invalidate performance and lead to non-compliance. For this reason, third-party certified products and competent installation are essential to ensure barriers meet regulatory requirements and remain effective throughout the building’s life.
On existing blocks of flats and other multi-occupied residential buildings, the fire risk of the external walls and cladding is assessed through a Fire Risk Appraisal of External Walls (FRAEW), carried out to PAS 9980. This code of practice sets out how a competent assessor appraises the cladding, insulation and cavity barriers as one complete system and grades the overall fire risk. The findings shape the building’s fire strategy and support the EWS1 form that lenders and valuers rely on.
Cavity barriers sit at the heart of that appraisal. Missing, wrongly positioned or poorly installed cavity barriers in the external wall build-up are among the most common findings, because they let fire and smoke bypass compartmentation and spread through the cladding cavity. Where a review calls for action, the remedial work almost always involves installing or reinstating cavity barriers and external fire barriers to restore compartmentation.
Ark delivers that barrier and cavity work. We install and remediate cavity barriers and external fire barriers to the specification set out by the external wall review and the building’s fire strategy, and we document every installation to support the golden thread required under the Building Safety Act 2022. This gives specifiers, building owners and Accountable Persons an evidenced record that the external wall system has been brought back up to standard.
Our team at Ark Fire Protection has extensive knowledge and experience in the installation of cavity fire barriers for various sectors including Commercial, New Builds, Healthcare (NHS), Student Accommodation, Industrial, Education, Residential, Facilities Management, Social Housing, and Insurance sector. We pride ourselves on our ability to provide bespoke solutions that are tailored to the specific requirements of each sector, ensuring maximum safety and compliance.
Every sector has its unique needs and fire safety regulations – our team of experts is well-versed in these requirements and can provide guidance on the most suitable type of cavity fire barrier for your sector.
Whether you need a fire barrier for a commercial building or a residential development, our team will work closely with you to understand your project’s specifications and deliver an effective solution that meets all necessary regulations.
Fire barriers are fire-resisting materials installed within cavities and concealed spaces to slow the spread of fire and smoke. They work by forming a physical barrier that maintains compartmentation where walls and floors alone cannot provide continuous protection.
Fire barriers help contain fire and smoke within designated compartments. They seal cavities and voids, preventing hidden pathways for fire spread, maintain compartmentation across walls, floors, and ceilings, and buy time for occupants to safely evacuate. By supporting the overall fire strategy, they protect both people and property while ensuring regulatory compliance.
Yes. Fire barriers can be retrofitted during refurbishments or remedial works where missing or defective barriers are identified. Installation must align with tested systems and the building’s fire strategy to ensure compliance.
Inspection is typically carried out through intrusive surveys, ceiling void access, or during refurbishment works. Fire risk assessments often identify areas where further investigation is required to confirm barrier presence and condition.
Missing or damaged fire barriers significantly increase the risk of rapid fire and smoke spread through concealed spaces. This can lead to regulatory non-compliance, enforcement action, and increased risk to occupants and property.
A cavity barrier is a specific type of fire barrier designed for installation in narrow concealed cavities – such as external wall cavities, party wall cavities, and floor cavities. A fire barrier is the broader category and includes both cavity barriers and larger external fire barrier systems used in roof voids, ceiling voids, and atria where the void is too deep for a standard cavity barrier. All cavity barriers are fire barriers, but not all fire barriers are cavity barriers.
Fire barriers and fire stopping both form part of a building’s passive fire protection strategy, but they perform different functions. Fire barriers are installed in concealed voids and cavities – spaces within the building’s fabric that are not visible during normal occupation – to prevent fire and smoke from spreading through hidden pathways. Fire stopping seals gaps, joints, and service penetrations in fire-rated walls, floors, and ceilings where services such as pipes, cables, or ducts pass through. Fire barriers protect the void; fire stopping seals the breach.
Yes. Cavity barriers are a legal requirement under Building Regulations Approved Document B in England and Wales. The regulations require that concealed spaces within a building’s fabric – including external wall cavities, party wall cavities, and floor cavities – are protected against the spread of fire. On residential buildings over 18 metres, the Building Safety Act 2022 imposes additional requirements on specification, installation, and documentation of cavity barriers as part of the building’s safety case.
BS 8414 is the British Standard test method for assessing the fire performance of external cladding systems, including the cavity barriers installed within them. The standard tests the complete external wall build-up – cladding, insulation, fixings, and cavity barriers together – rather than individual components in isolation. This is important because the interaction between components affects fire performance; a cavity barrier that passes component testing may not perform correctly within a specific wall system. On residential buildings over 18 metres, BS 8414 test evidence is one of the accepted routes to demonstrating that an external wall system meets the requirements of the Building Safety Act 2022.
PAS 9980 is the code of practice for carrying out a Fire Risk Appraisal of External Walls (FRAEW) on existing blocks of flats. It assesses the cladding, insulation and cavity barriers as a complete external wall system and grades the fire risk. Cavity barriers are a key part of that assessment: if they are missing or incorrectly installed, fire can spread through the external wall cavity. Where a FRAEW identifies barrier defects, Ark installs and remediates the cavity and external fire barriers needed to bring the wall system back into compliance.
On a higher-risk building, the external wall system – including its cavity barriers – is part of the evidence the Building Safety Regulator reviews before construction (Gateway 2) and before occupation (Gateway 3). Because barriers are hidden once the facade is on, missing or unevidenced barriers are a common cause of Gateway delay. Capturing the evidence as each barrier is installed avoids re-opening the wall later.
It varies by contract, and that ambiguity is exactly where barriers get missed. On many projects the facade contractor fits them but any failure is treated as a passive fire failure. Ark coordinates the barrier line with the facade package in writing so the scope is owned, not assumed, and documents the interface so responsibility is clear.
Where an external wall review identifies barrier defects on an eligible building, the remediation can often be delivered as part of a funded cladding programme. Ark installs and reinstates cavity and external fire barriers to the specification set by the review, and evidences the work to support funding sign-off and the building’s safety case.
