A smarter approach to cavity barrier remediation. Meet the Retrofit Barrier System at London Build 2026
Every year, London Build brings the construction industry together in the capital, where innovators, visionaries and the people responsible for delivering projects all meet to see new ways of working.
On 25-26 November at Excel London, we will be part of the conversation by showcasing our Retrofit Barrier System on stand G84.
Ahead of the show, in the following blog we look at why cavity barrier remediation is needed, why the usual fix can create disruption, and how the Retrofit Barrier System offers a different route for suitable buildings.
What do cavity barriers do?
In building construction, many external walls have a cavity between the outer leaf and the inner structure. In the event of a fire, the space can potentially allow fire and smoke to travel unseen. Cavity barriers close that void at set points to cut off this potential route for fire and smoke spread.
Without barriers in place, cavities can create what is known as the ‘chimney effect’, where hot gases are drawn upwards, and fire can potentially spread floor to floor behind the façade, bypassing fire-resisting construction inside the building.
In many existing buildings, cavity barriers were never fitted, were fitted in the wrong place, or were installed with gaps. These defects are hidden, and often only come to light once the external wall is assessed. Once found, they have to be dealt with, hence the UK-wide push on fire remediation, and growing legislation.
The limitations of the conventional fix
The established remedy to this challenge is to open up the wall. Sections of the outer leaf are removed, barriers are installed or replaced, and the wall is rebuilt.
It works, but it is a large and costly undertaking. Scaffolding can stay up for many months, removed materials must be stored or disposed of, exposed areas may need weather protection, and each step requires close co-ordination between different trades. Projects are often measured in months, and on larger buildings it is not uncommon for this to reach in excess of a year.
On occupied buildings, residents occasionally have to move out of the building while the work is underway. In instances where residents don’t need to be rehoused, those residents are living with noise, access restrictions, and scaffolding. In either event, there is disruption to live with.
Why reducing disruption is so important
Expectations are changing. The UK Government’s Code of Practice for the remediation of residential buildings in England expects disruption to residents to be kept to a minimum.
Many buildings need remediation, but the labour and access equipment to deliver it are finite. As a result, a long programme of work on one building delays the next, and so on. The focus, therefore, is on delivering that work safely, quickly, and as easily as possible for the residents who live there.
Meet the Retrofit Barrier System
On suitable buildings, the Retrofit Barrier System, as visitors to London Build will see, closes the cavity from the outside instead of opening up large sections of the wall to reach it.
InstaFibre 034, an A1 non-combustible recycled glass mineral wool, is injected through small 22mm holes drilled in the outer leaf. The cavity is filled to a controlled density, which removes it as a route for fire and smoke while the façade stays in place.
Every building is surveyed and assessed for suitability before work begins. Installation is inspected throughout, with density measured and records kept, so the speed of the method doesn’t come at the cost of assurance.
The benefits for remediation projects at a glance
Installed externally. Work takes place from outside the building.
Small access holes. 20mm or 22mm openings replace large-scale removal of the outer leaf.
Less disruption. No strip-out and rebuild, and less time with access equipment on the building.
Residents can stay at home. No-one needs to be relocated.
Fast installation. Typical rates of around 100-125m2 a day, depending on the building and site conditions.
Shorter timeframes. Projects that could run for many months with façade removal can be completed much faster. The Retrofit Barrier System is up to 75% faster than typical façade replacement.
Built for scale. The system has been used in numerous large-scale remediation schemes and suits both individual projects and multi-building schemes.
Backed by independent evidence
The Retrofit Barrier System holds a Kiwa BDA Agrément (BAW-21-206-S-A-UK), and has also been tested to BS 8414-2. It uses InstaFibre 034, a recycled glass mineral wool which is classified A1 for reaction to fire, the highest classification. The Retrofit Barrier System also has Building Safety Regulator Gateway 2 approval for remediation works using the system on existing high-risk buildings.
See it at London Build 2026
Visitors to London Build 2026 can get a first-hand look at the Retrofit Barrier System. It will be demonstrated on Stand G84, 25-26 November at Excel London.
Weighing up options for a remediation project? Bring along project details, connect with our team, and discover whether the Retrofit Barrier System is the right choice for your project.
To arrange a meeting in advance, please contact retrofitbarrier@instagroup.co.uk
To register for free tickets to London Build 2026, visit londonbuildexpo.com/
