Wall mount tv on plasterboard wall with 4.5cm cavity and metal studs.

Discussion in 'Builders' Talk' started by MarkQuin, Jun 25, 2022.

  1. MarkQuin

    MarkQuin New Member

    Hi all,
    I'd like to wall mount a 55" TV, ideally on a cantilever bracket. I've done it on a brick wall before, but not on a cavity wall which I have now, so looking for some tips...

    The setup
    The wall is 1.5cm plasterboard. Behind it, there is a cavity of 4.5mm to a concrete wall. So the total distance from concrete to plasterboard face is 6cm.

    There are 2 metal (presumably steel) studs between the plasterboard & concrete, about 60cm apart.

    3 questions
    1) I could settle for a basic, non-cantilever, flat mount and fix into the metal studs with metal expansion anchors. I assume they would hold the weight without too much flex?
    I'd settle for that if necessary, but...

    2) For a cantilever bracket, I could use these to go into the concrete and bridge the cavity, but the max recommended cavity is 4.5cm (not the 6 I have). I guess if I used, say 8 of them, it would hold though. Thoughts?

    3) Any other suggestions for better ways to fix a cantilever bracket without ruining my wall / TV?!

    Thanks in advance
  2. BiancoTheGiraffe

    BiancoTheGiraffe Screwfix Select

    Stick some long frame fixings through the cavity into the blockwork...

    100mm will do... 40mm of fixing into the concrete will be fine (any further and you may hit a void in the blocks, as has happened to me several times at my place)

    Stick as many fixings in as the bracket allows
  3. MarkQuin

    MarkQuin New Member

    Thanks so much.

    Yeah, the "as many fixings as possible" tip is excellent! I don't know why I suggested stopping at 8!

    The 100mm fixings were also something I thought about, but I guessed the thickness of the bracket might add on another 10-15mm which would mean the 100mm screws would only have about 25mm grip and 75mm leverage on the screws, so I went for the 120mm. Just thought they'd be safer. Hadn't thought about the risk of going through to a void, thanks for the tip.

    Really appreciate your advice, thanks again.
  4. ginger tuffs

    ginger tuffs Screwfix Select

    if you cut a square of 18 mm plywood and fix that to studs you will spread load easier then fix tv bracket to that
    Last edited: Jun 26, 2022
    MarkQuin likes this.
  5. Bob Rathbone

    Bob Rathbone Screwfix Select

    Getting a good fix to the steel studding will be difficult. Plasterboard screws do that very well, but the studs are very thin and only expected to support the distributed weight of plasterboard. The chances are that the screws will pull through the thin steel studs, especially with a cantilever bracket.
    MarkQuin likes this.
  6. McDaddy1815

    McDaddy1815 New Member

    I used Rigifix fixings for this exact scenario. Used with a 50 inch on a cantilever corner bracket, never moved.
    MarkQuin likes this.
  7. MarkQuin

    MarkQuin New Member

    Thanks. I assumed the studs wouldn't hold a cantilever, but thought they might be enough for a basic flat one.
  8. MarkQuin

    MarkQuin New Member

    Thanks, I googled 'Ringfix' but didn't find anything. Did you mean the Corefix one I linked?
    If so, did you use the 100mm or the 120mm fixings?
    Thanks in advance.
  9. Notnowvicar

    Notnowvicar Active Member

    use corefix...all my kitchen base units are suspended off the floor using them to give a floating look...have not moved in 4 years.
    MarkQuin likes this.
  10. McDaddy1815

    McDaddy1815 New Member

    It's rigifix. They are very similar to the corefix by the looks of things, just the original version
    MarkQuin likes this.
  11. MarkQuin

    MarkQuin New Member

    Sorry! My mistake. Small screen, old eyes!
    I guess you used the M8 / 100mm version?
  12. McDaddy1815

    McDaddy1815 New Member

    Yes I think so. I used the longest ones I could find anyway.
  13. Dave1988

    Dave1988 Member

    Corefix is all you need. My house is same as yours got 80kg rads and stuff on them lol. And a 75inch tv

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