Mount TV to brick behind plasterboard (large gap)

Discussion in 'Builders' Talk' started by icekay, Nov 25, 2018.

  1. icekay

    icekay New Member

    Hi all,

    I wanted to get fixings long enough to be supported by the brick wall behind the plaster, however the gap seems much wider than what I see mentioned for most common type fixings - 67mm from the front of plaster to the wall behind. I can't easily measure the plasterboard thickness but assume the gap itself to be at least 55mm wide.

    Is there any tried and tested fixing that could be used to bridge this much of a gap? I looked around but couldn't find suitable fixings so was wondering what other people recommend in this situation.

    Many thanks.
     
  2. chippie244

    chippie244 Super Member

    Cut the plasterboard out where you want to mount the telly, pack out with timber and then mount your telly.
     
    WillyEckerslike and DIY womble like this.
  3. furious_customer

    furious_customer Screwfix Select

    Mount the telly to the timber or brick?
     
  4. Dam0n

    Dam0n Screwfix Select

    I would use some frame fixings for the job. As above use the timer to pack out the space and stop any plasterboard being pulled in and cracked.

    Go through the wood (only a spacer essentialy) and into the brick for a proper fixing.
     
  5. icekay

    icekay New Member

    Thanks everyone - hadn't thought of using timber and sounds like this would be as good as fixing directly to the wall behind. The thought of cutting a large hole in the plasterboard of a brand new house is a bit daunting but sounds like something an amateur like me can manage :)
     
  6. chippie244

    chippie244 Super Member

    If you are neat and get the timber thickness just right you can stick the pb back on and fill.
     
  7. 2shortplanks

    2shortplanks Active Member

    Allsorts likes this.
  8. chippie244

    chippie244 Super Member

    fostyrob and Dam0n like this.
  9. Allsorts

    Allsorts Super Member

    The other neat (no p'board cutting) method is to drill through in to the wall and resin-in some threaded studs - 10mm or possibly 12mm should be more than fine as there would be 4 of them?

    Cut the studs to length (full depth of hole, void and enough for the bracket, washer and nut.) Finish cut ends neatly so nuts go on easily afterwards...

    Screw on a nut to just below p'board top surface then a washer which would be sunk level once bolted down firmly, enlarge the holes in the mounting bracket to suit, slip it on, washer and last nut.
     
  10. Baxi Boy

    Baxi Boy Active Member

    You could get some 6 inch Fischer type bolts that expand like rawlbolts,window fitters sometimes use them.May sure of the type of inner wall you have,as it maybe thermolite blocks which don’t take much weight like concrete would.
     
  11. furious_customer

    furious_customer Screwfix Select

    Before you go to too much hassle, it might be worth checking the weight of your TV.

    A new 55" LED TV only weights about 17 - 18Kg - hollow wall anchors into the plasterboard should be able to support that weight.
    Alternatively, you could just cut the plasterboard out until you expose 2 vertical studs then cut a piece of 12mm MDF to match the size of the plasterboard you removed - bolt your TV bracket securley to this and then screw the MDF to the studs in the cavity you created. This is what I did with a >20Kg over-mantle mirror in my living room.
     
  12. icekay

    icekay New Member

    Thank you all for your suggestions. I had a bit of time this evening and studied the wall by knocking around, and feels like dot and dab (outside wall, terraced house). The "solid" knocks then sound hollow by knocking around it + are not aligned either horizontal or vertically.

    I drilled small holes where the mount will eventually go, one of which through the "solid" part - harder than plasterboard but still pretty easy to drill into, very white powdery material came out (I assume adhesive). The TV weighs 36kg and I'm sure some would say the plasterboard can take it but I'm just a bit worried it won't.

    Anyway I had previously measured some holes that the builders made and forgot to consider that they drilled them into the block work, therefore the depth from the outer wall (incl. plaster) is more like 45mm rather than 67mm. Perhaps the fixings mentioned above by 2shortplanks (https://www.amazon.co.uk/dp/B0032P5K96/ref=psdc_1938475031_t3_B072JYXJL6) would actually be OK for this.

    As I strongly suspect it is dot and dab I'm now wary of cutting into the plasterboard, though it also occurred to me that there are some wall sockets I could take apart to inspect the wall further and will take a look tomorrow.

    This is probably a 5 minute job for a professional so forgive my novice approach!
     
  13. Allsorts

    Allsorts Super Member

    Any idea what the brick/block wall behind is made of - type of block?
     
  14. WillyEckerslike

    WillyEckerslike Screwfix Select

    There's also an M6 version of the Rigifix -That would be more than adequate.
     
  15. Allsorts

    Allsorts Super Member

    Is it long enough tho'?
     
  16. RolandK

    RolandK Screwfix Select

    Successfuly used Dryline Pro fixings in dot and dab for kitchen cabinets.
     
  17. icekay

    icekay New Member

    Took one of the sockets apart and it's some sort of concrete block. Plasterboard is 15mm thick and annoyingly I get different gap depth readings depending on the hole I poke the vernier caliper into - ranging from 20 to 30mm gap (35-45mm in total).

    Ordered some M6 Rigifix which should arrive in the next few days, given they're 90mm long at least half will go into the wall. The TV and mount will put around 40kg on 4 fixings so I reckon this will be sufficient - the pack actually comes with 6 fixings but maybe overkill!
     
  18. icekay

    icekay New Member

    Just to feedback on this, I got the M6 Rigifix yesterday and got started on the necessary 12mm holes - first two went perfectly, fixings went in easily and the entire thing felt REALLY sturdy.

    Sadly I wasn't so lucky with the other 2 at first as there as the wall had some sort of metal and seemed to be brick rather than concrete, so much so that the rawlplug part wasn't a snug fit. Had to drill the final holes elsewhere and use some plaster filler to cover up the ones that went wrong.

    Before putting the TV up I lifted my own weight on the TV mount itself and seemed rock solid, so it worked out great in the end!
     

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