VESA Mount: Corefix alternatives for bigger gap (65mm) between plasterboard and concrete

mp3ireland2

I bought some corefix screws to hold up a dual monitor vesa stand. Unfortunately when I drilled a pilot hole it seems to be 65mm from the front od drywall through to the concrete. The corefix only cover a 45mm distance to the concrete.

There's no stud in a useful position. I'm wondering if there's any simple way to mount this without having to cut into the drywall and installing a beam bewteen two studs. I could fix some wood outside the drywall which probably wouldn't be noticed with monitors in front of it, but it wouldn't be very slick!

I'm fairly novice to DIY so if I was cutting into the plasterboard I'd probably get somebody else to do the job, so just checking if anything I could manage!

Thanks,

larchielads

Buy 65mm or longer corefix screws??? U can deg get 100mm ones just googled em

mp3ireland2

https://www.boards.ie/discussion/comment/121270922#Comment_121270922

the screws are 100mm that I have but they are only to be used for a 45 mm gap. The metal sheath that goes into the plug won't be able to support a bigger gap.

larchielads

Could u buy another pack and double up on the steel core? Drill further and put one behind the other??

mp3ireland2

https://www.boards.ie/discussion/comment/121272019#Comment_121272019

interesting idea but i think the break in the core would mean the load wouldln't be transferred. Can't find anything similar that does a longer distance :-(

10-10-20

Somebody on here before suggested to hammer in an express nail and then put a rawl-plug into it before screwing in the fitting?

https://www.mcmahons.ie/rawlplug-express-expansion-anchor-8-mm-x-150-mm-55356

mp3ireland2

https://www.boards.ie/discussion/comment/121272216#Comment_121272216

Hi, would there be a diagram of this any where? I've looked for youtube videos. So I drill through the plasterboard and concrete to total depth of over 150mm at the appropriate diameter, and hammer one of these in. These have an opening at the top is it? that a rawl plug will fit into? I can't find a picture at an angle that shows me the top.

EDIT: I found some photos and see they are hallow. Would be concerned about a plug gripping onto the smooth surface. It is almost like the oppisite of the corefix, the metal sleeve around the plug.

It's certainly a nice simple idea

ted1

How heavy is the bracket? I can’t image the weight would be much. As long as the screw are in the concrete. It should hold.

mp3ireland2

https://www.boards.ie/discussion/comment/121272284#Comment_121272284

Yeah they are quoted as 4 of these hold 100kg, with weight of bracket and the two monitors i'd say it's going to be about 10kg. There are no swignig arms on the monitor stand, so no large forces due to the distance from the wall. Maybe i should just chance it! The metal part is only 50mm long however, so woudn't get to the concrete at all, so wouldn't be any addition

Shoog

I can tell you that these things are amazing

Bullfix

i hate plasterboard fixings but these ones can take a mighty load and they are fairly full proof to install.

Available from Screwfix and quite expensive but well worth it

mp3ireland2

https://www.boards.ie/discussion/comment/121272626#Comment_121272626

They do look good but I think i'd be too concerned about the close proximity of the holes for on the mount, the 20mm holes would be very close to over lapping.

10-10-20

https://www.boards.ie/discussion/comment/121272279#Comment_121272279

Yes, they are a hollow tube but have a gap/groove cut into them so that they force-fit into the concrete. That acts as resistance for the rawl to gain resistance in the tube.

mp3ireland2

What about a 120mm or 150mm concrete screw? Would that bend with the 65mm gap between wall and plasterboard under a 10kg load?

https://www.screwfix.com/p/turbo-tx-tx-double-countersunk-self-drilling-multipurpose-screws-6mm-x-150mm-50-pack/535vv

I'd probably need a longer drill bit

10-10-20

https://www.boards.ie/discussion/comment/121273208#Comment_121273208

10kgs over 6.5cm's with multiple screws, hardly. Give it a go and use a washer on the head so it doesn't pull through the metal. You can always go back to express nails after.

mp3ireland2

https://www.boards.ie/discussion/comment/121273276#Comment_121273276

Have ordered some of those and a longer 6mm drill bit. Might need to widen the 8mm holes in my bracket a little, unsure what the major diameter will be on the 7.5mm thread. Could be a week or so before I get to it but i'll report back!

mp3ireland2

Very oddly ..I went to drill 160mm hole today and there was no significant resistance.... Not sure what the wall is made off! That 65mm resistance must not have been the wall.

Anyway I figured I'd take a gamble with some plugs. It's about 10kg and not a great moment on the force. I figure worst case I'll wreck some plasterboard and get somebody in to sort that and put a support behind it at the same time.

Fingers crossed!