• In this Bitesize CPD we will be looking at basic deflection heads used to accomodate movement in soffits above plasterboard partition walls.

    We will look at causes, effects and remedies to common defects picked up by FCM’s Clerks of Works during their site inspections.


    Deflection heads are used within plasterboard partitions when needing to allow for movement (up, down or both) within the structure at the head of a partition. This movement (or deflection) is created by live and dead loads on the floor or roof above. The partition system below needs to accommodate this movement without transferring load onto the metal studs.

    Incorrectly installed or missing deflection heads to partition walls are one of the most common defects that we pick up on site.


    • 15mm plasterboard instead of 19mm flexible core board.
    • Head board not to full width of head track.Will not be fire and smoke proof.
    • Should be separate strips above each head track,
    • Will not allow specified 15mm of deflection when the wall board laps over from the metal stud.


    • Plasterboard tight against ceiling – should have 15mm gap between top of board and soffit to allow for slab deflection.
    • Insufficient fixings at top of wall as fixing strip is missing.


    Installation  details for basic deflection head from British Gypsum site guide:


    The consequences of getting it wrong:


    Download The British Gypsum site guide and good practice guide here.



    Steve Farrell 
    T: 07714234380
    E: stevefarrell@fcmltd.co.uk 
    L: linkedin.com/in/stevefarrellfcm

    Fox Curtis Murray are a building consultancy specialising in providing Clerks of Works services and Quality Control inspections.

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