Mount TV arm to new MDF tv unit

will56

Hi,

New MDF tv unit installed today

Want to install a TV arm to get the Television out of the way and leave the whole set up looking neater

MDF unit is mounted against the back wall

The wall is dab and stick plasterboard onto cavity block

The carpenter used 122mm screws to try and mount the arm but there is some obvious flex in the back of the unit when weight is put on the arm

Is there a better way to secure an arm to the unit and the wall ?

Should we put extra fittings around the arm to secure the back to the wall ?

Would corefix fitting work ?

I think the back is 18mm thick oak veneer MDF

This is the arm

https://www.amazon.co.uk/gp/product/B075YP6SVY/ref%3Dppx_yo_dt_b_asin_title_o01_s02?ie=UTF8&psc=1

Picture of unit attached

irishbuzz

It's not insulated plasterboard correct? (i.e not drylining)

What is the depth from the unit surface back to block? I've used Corefix before and it's a good product but it requires a maximum of 45mm back to block but that is stretching it.

seamus

Sounds like he drilled through the unit and the block to get a fixing? I guess the issue here is that the arm is partially "mounted" on the MDF unit. So any weight on the arm causes flex which then spreads out through the unit. Are you sure the back panel is 18mm MDF and not a piece of 2-3mm board?

The right way to do this would have been to cut a section out of the back of the unit before it was installed. One problem is that the backplate of the arm needs to sit flush with the back of the unit - if you cut out a section and fit it directly to the wall, the arm probably won't sit down flush. You can't really just ignore this. MDF doesn't tolerate constant load well, the whole thing will be a warped mess in months.

If the backplate really is 18mm MDF:

1. Use a pencil to trace around the position of the backplate in the unit, and then remove it. You now have a rectangle drawn on your unit. We'll call this "box 1"
2. Using a ruler, draw another box around this one, that is 10mm wider on each side. Call this "box 2". Draw an arrow on box 2 to indicate which way is up.
3. Draw another box around box 2, which is 5mm wider on each side again. Call this "box 3"
4. Using an oscillating cutter, cut out box 3 as one whole piece and hold onto it, you're going to need it.
5. With your new cut-off piece, cut out box 2. That is, trim 5mm off around the edges of the piece. A jigsaw is probably easier for this, but whatever works for you.
6. Re-mount your TV bracket with your cut-off piece placed between the backplate and the wall. Use the holes that are already in place and make sure to orient the cut-off correctly. You can tighten it quite a bit, it won't crack like real wood, but don't go mad.

What you should have now is the bracket remounted in the unit with a 5mm channel around it. This gap prevents the TV bracket from putting any pressure on the rest of the unit.

If the carpenter is as lazy as he sounds, there may be another 18mm gap between the back panel and the wall where the skirting board is. So you'll need another piece of wood to mount the bracket on to keep it flush. If it's more than 18mm, then you need to consider the screws being used; you might want to upgrade to 150mm anchors with a heavier gauge.

If the back panel is actually just a thin sheet, then you can follow the same process, but really all you have to do is use a stanley knife and a steel ruler to cut out one section of panel and then mount the TV bracket directly onto the wall.