Wall anchors for "double layer plasterboard and PIR insulation"

RoyMi6

RoyMi6

RoyMi6

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Looking to hang a mirror (about 10kg) on a pair of screws on the wall of our newly renovated living room. Weight is likely to be 90% downwards rather than any kind of "pull out" force.

Hindsight is 20/20, but during the refurb I didn't notice I wasn't going to line up with the original cornicing in the ceiling so ended up having double board the wall to make everything line up.

Now that I'm looking to hand something on the wall I suddenly realise that I've got a slight issue in that the wall is now made up of:
2mm plaster skim coat -> 12mm plasterboard -> 12mm plasterboard -> 25mm insulation

There's then about a 10mm gap before "random stone" wall (1890 victorina build).

I'm not sure what fixing would even work with such a "thick" wall... None of the example in these kind of videos (https://www.youtube.com/watch?v=mIEY3E4fiDk) will likely work as either the bits designed to grab onto the back of a sheet won't expand (because there's another sheet blocking it) or there's not enough room to put things through (like the various toggle ones) because of the insulation and then small gap at the very back.

The self drilling/spiral plasterboard screws always get awful reviews but that's aways in comparison to something else... I'm sure if you compared it to "just a screw" (like I have at the moment) they might be better... but got nothing to base that on :)

Any suggestsion welcome!
 
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I would go frame fixings I guess
I have used the plasterboard screws in the past for 10kgs they would likely be fine. They make a lovely mess when you remove them though.

Something like this, assuming you have a decent long drill bit
https://www.screwfix.com/p/rawlplug-kkr-pa6-nylon-frame-fixings-8-x-100mm-12-pack/6939g

Edit just to say, the screw in plasterboard ones are only as good as the board itself, if its not that strong they cant fix that. But in good board they are pretty good all things considered
 
When I was working we used these and they were ok - if you don't have the depth we used a masonry drill to drill into the wall -push them in then crimp up with the tool. You can get them with different length plain shaft (or you could)
https://www.toolstation.com/rawlplug-interset-metal-cavity-wall-fixings/p56222

Don't use the alloy screw in ones - they are ok for small stuff but i wouldn't put a mirror on them.
 
Try these big bar steward Corefix jobbies :

https://www.screwfix.com/p/corefix-...VyrTtCh1HXgBFEAQYFCABEgKBu_D_BwE&gclsrc=aw.ds

There are a few different types and you can get them in smaller packs from other sites. I used them to put up a heavy mirror and I also put some filler in the hole I drilled before I put the plug in, combined that metal insert you end up with a very solid installation! I think I used the ‘Corefix Air’ product.
 
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Some of the longer Fisher Duopower fixings might be rated strong enough and long enough to hold 10kg on two layers of plasterboard? Have a look on their spec sheets.

Edit: Their load tables do give a rating for 2x12.5mm plasterboard.
 
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Perfect, those fisher duopower ones look like they've got potential. It's one layer of fireboard then one of standard, so should be plenty on a pair of them :)
 
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