11.2.10 Junctions and interfaces
Junctions and interfaces shall be suitably detailed, built to appropriate tolerances and provide satisfactory performance.
The use of closed panel systems, particularly where finished linings or claddings are installed may introduce junctions and interfaces between adjoining units that are not common in traditional construction.
The junctions of panels should be designed with appropriate tolerances to avoid excessive deviation:
- to external faces of adjacent panels, which may impact cavity widths, installation of insulation and cladding as well as performance of cavity barriers or fire-stopping
- to internal faces of adjacent panels, which may impact continuity of acoustic or fire-resisting linings or installation and fit of surrounding construction (eg staircases).
The manufacturer and designer should consider:
- guidance on jointing methods for structures, claddings, openings, and services passing through building elements given in BS 6093
- undertaking of mock-ups or trials to ensure satisfactory fit and tolerances can be achieved.
Closed panel timber frame
When fixing closed panel timber frame walls to the substructure, they should be installed in accordance with the manufacturer’s design and Clause 6.2.4 and 6.2.5.
Closed panel light steel frame
When fixing closed panel light steel frame walls to the substructure, they should be installed in accordance with the manufacturer’s design and Clause 6.10.10.
Floor cassettes
The design should clearly specify where connections are required to provide lateral restraint or robustness at floor to wall junctions. Installation instructions should be given in the System Manual and Installation Manual. Where floor cassettes incorporate permanent floor decking, care should be taken to design cassette junctions at thresholds or intermediate walls to minimise large joints in open rooms.
Adjoining cassettes should be securely fixed to ensure structural continuity and to avoid differential deflection in accordance with the manufacturer’s design.
Junctions between decking to adjoining floor cassettes should be designed to achieve necessary tolerances to allow installation of floor coverings. Interfaces of decking may either be designed as a butt joint or by using a transition piece to accommodate minor tolerances between decking finishes.
Cassette junctions should:
- have a nominal 3mm gap at decking joints
- be filled with an appropriate gap filler or covered with a cover strip
- be kept clear of debris
- not exceed 2mm level difference between floor decking at any position.
Foundations
Foundations should be installed to tolerances in accordance with the System Manual. The foundation tolerances should consider:
- level of foundation
- straightness of foundations
- dimensional tolerance
- level between foundation and substructure brickwork
- squareness of foundations.
Last updated: 2nd January 2025