Frequently asked questions

Introducing UNisystem

UNisystemLB is a loadbearing light gauge steel framing system, suitable for low to mid rise buildings of up seven storeys, with a maximum final finished floor level of 18 metres. It is ideal for houses and medium height apartment blocks, as well as for education, health, defence and other public sector buildings.

UNisystemSFS is an infill panel system incorporated into reinforced concrete and steel frame structures for mid to high-rise developments and delivers reliable and robust buildings for student accommodation, later living and apartment block developments, whether you’re delivering one building or several in a single setting.

Panels can be manufactured at a minimum width of 200mm and maximum width of 8,400mm, and a minimum height of 1,000mm and maximum of 3,200mm, providing flexibility to any project.

British Offsite is standardising traditional construction into an offsite (‘MMC’) model.

Using standardised materials commonly found across the construction industry such as windliner sheathing board, superfil and rainscreen slab insulation, ventilated and non-ventilated cavity fire barriers, and most windows and door profiles. We integrate these products into our light gauge steel frames offsite, on our automated assembly line, saving time and resources usually required for manual installation on site. One panel can combine the work of up to five trades.

Pre-manufacturing panels this way increases project productivity, certainty about the time, resources and materials involved in your project, and greater programme and budget predictability overall.

UNisystemSFS is an infill panel system for reinforced concrete or steel frame structures. It can be used for mid to high- rise developments and includes UNipanelSFS for external walls and UNiwallSFS for internal compartmentalisation.

Each panel is manufactured using standard materials and assembly, but can be adapted to specific structural, thermal, acoustic and fire requirements, calculated on a site-specific basis. External wall insulation, external cavity barriers, external DPC and internal battens can all be altered to meet specific needs.

UNisystemLB is a loadbearing light gauge steel framing system suitable for low to mid-rise buildings up to seven floors, with a maximum final finished floor level of 18 metres. The system includes UNipanelLB for external walls and UNiwallLB for internal walls.

Working in combination with UNifloor or another compatible floor system, UNisystemLB can provide the structural requirements of a building; no additional supporting structure is required.

Every panel is designed and adapted to the specific structural, thermal, acoustic and fire requirements, designed on a build-by-build basis, manufactured using standard building materials and assembled in our state-of-the-art Horizon factory in Braintree. External cavity insulation, external cavity fire barriers, external DPC and internal battens can be added to meet specific needs.

UNisystemSFS and UNisystemLB are competitively priced products when compared against other 2D panelised steel frame systems when including the full set of materials and manual processes involved in completing these traditional panels onsite.

British Offsite’s panels integrate multiple materials and processes offsite. Windliner, insulation, vapour panels, firestopping, windows and doors can all be pre-installed. The work of up to five trades can be combined into one panel.

The comparison table in our News & Views section shows what’s included in UNisystem in contrast to a traditional 2D panelised system, and how prices should be compared.

British Offsite has NHBC Accepts certification for both product ranges.

Specifications and performance

British Offsite can support the design of your building from pre-planning onwards and as late as RIBA stage 4.

Technical designs can be produced based on the elevations and general arrangement drawings you provide. When available, we also need to see the window schedule.

The current build-up of UNisystemLB using a 200w stud is 425w. With the arrival of a 100w stud in Spring 2024 this can be reduced by 100w to as little as 325w.

Changing the size of stud may impact on the u-values currently achieved with the 200w. British Offsite can work with developers to achieve the balance between wall build-up and u-values they need.

UNisystemSFS and UNisystemLB both meet all regulatory requirements for thermal, acoustics and fire performance. Specific performance numbers are provided below.


  • Fire rating UNipanelSFS up to 90 minutes
  • Fire rating UNiwallSFS up to 90 minutes
  • Acoustic insultation 48dB minimum (52dB nominal)
  • U value on UNipanelSFS 0.24-0.13 W/m2K


  • Fire rating UNipanel LB up to 60 minutes
  • Fire rating UNiwallLB up to 120 minutes
  • Acoustic insultation 48dB minimum (52dB nominal)
  • U value on UNipanelLB 0.29-0.12 W/m2K

Environmental credentials

UNisystem is unable to incoporate natural insulation currently, due to our production processes and the routing of multiple orders. However, it is worth noting that the insulation we we use, Superfil 34, is a 100% recycled and recyclable product made up of 80% waste glass, plus unbounded mineral wool insulation.

With the launch of our Horizon factory in summer 2023, British Offsite is focused on achieving several externally audited environmental benchmarks. In 2024 we expect to have Environmental Product Declarations (EPDs) to EN 15804+A2 with BREEAM, LEED, DGNB. Independent EPD verification will follow to ISO 14025 standards. Product Carbon Footprint Declarations to ISO 14067 are planned, which will involve Carbon Footprint Analysis in line with Green House Gas Protocols and ISO 14064 Standards. The following Scope 3 emissions will also be assessed: CO2, CH4, N2O, HFCs, PFCs, SF6, NF3.

Operating sustainably across our whole value chain is an embedded commitment at British Offsite, to support our Carbon Net Zero objective. Through external auditing, increased measurement and performance management, we expect to build on the many initiatives we already have in place and to set a series of milestones to achieving Carbon Net Zero.

Current initiatives include solar panels on our factory roofs, the use of 38% recycled steel, waste management and recycling systems, use of an insulation layer made from recycled bottles, and utilisation of durable 100% recycled packaging.

We’re committed to a Fabric First approach, minimising waste and energy use in the process of production and delivering buildings and homes that are highly insulated and energy efficient too.

Programme delivery

Please contact British Offsite to discuss our turnkey solutions.


UNisystem installation is normally undertaken by your reinforced concrete or steel frame contractor or by British Offsite. Panels are manufactured ahead of site requirements and stored securely pending delivery to site.

Panels are lifted immediately into place from our purpose-made delivery vehicles and fixed into place via fixing brackets and are fixed into the adjacent panel/structure and the reinforced concrete slab, as required.

Panels over 5 metres in length are temporarily propped, in line with the British Offsite installation manual. Props can be removed as soon as the reinforced concrete slab for the floor above has cured.

British Offsite provide complete installation guidelines to facilitate the installation of all products as well as lifting plans and RAMS. We also have our own fleet of vehicles which includes HGVs of different sizes and technical capabilities, so we can meet different needs. All vehicles are purpose-made to carry UNisystem products safely and securely. By managing our own fleet, we have the flexibility to choose exactly the right HGV to carry specific lengths of panels, or a vehicle that is best suited for a particular site setting.