• Not Assessed


  • Design
  • Manufacture
  • Construction


  • Petra Modular UK Ltd. Steel-Framed Modular Volumetric Building System

Petra Modular (UK) produce a steel framed, volumetric build system. The modules are manufactured at our facility in Birmingham. The Petra Modular (UK) build system utilises a hot rolled structural steel frame. The sizing of the structural frame members is dependent upon the production of site-specific structural calculations, but generally consists of RHS corner and intermediate columns with PFC floor and ceiling beams. The factory works can include both internal and external finishes, the extent and level of which can be tailored to suit the needs of the developer and site-specific constraints.


Petra Modular UK Ltd. Steel-Framed Modular Volumetric Building System

System Description

The Petra Modular (UK) Ltd. modular volumetric building system is constructed utilising hot-rolled steel primary floor and ceiling beams, columns and bracing with cold rolled light gauge steel floor, external wall and ceiling infill panels. The system is designed to be stacked up to 5 modules high, either off a podium at first floor level, or off a ground sub-structure. The system can be configured to deliver detached, semi-detached and terraced houses and apartment blocks. The system can be manufactured to include a wide range of finishes internally and externally depending on project requirements. The level of factory and site fitted finishes can also be tailored to project requirements. Typically, modules are manufactured with basic mechanical, electrical services and plumbing services, fire detection and protection services, windows/doors, internal wall/ceiling linings. Roofs and cladding may be factory or site installed. Modules are weathertight for transport to site.

Durability Assessment – Minimum 60 Years

Limits on scope

  • Maximum 5 storeys for residential use subject to structural verification;
  • Fire protection information submitted for this assessment is limited to structures with a top storey height not exceeding 18m (measured in accordance with the Building Regulations 2010, as amended 2019, Approved Document B Diagram D6). 60 minutes structural fire resistance is required in accordance with Approved Document B, Table B4. Structures outside these parameters are not included in this assessment. As future project configurations may differ from those used for this assessment, all projects must be subject to individual fire mitigation assessments.
  • Bottom members in contact with foundations/sub-structure must be fully isolated from contact with moisture from the ground or external sources;
  • Where modules are located next to the ground, the void below the lowest module must be cross-ventilated a minimum of 1500mm2/m of external wall or 500mm2/m2 of floor area.
  • The ground below modules should be sealed to limit the moisture entering the void. Where the ground level in the void is below external ground level, consideration should be given to drainage.
  • Where insulated render and/or insulated brick slip cladding systems are to be used, a minimum 15 mm wide drained cavity must be maintained behind the insulation;
  • A chartered structural engineer suitably experienced in the design of this type of structure must be engaged for the structural analysis and design.
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