Heavy load mounted on aerated concrete blocks. Need advice on if I'm doing the right thing.

Submitted by T3zcat t3_11axb09 in DIY

Hi All,
I'm trying to mount a tv to a wall that's made from aerated concrete blocks, and I'm facing a slew of issues. So the concerns are:

  • The plugs will pull out (see this video),
  • The use of resin filler is a no go (previous owner had it, took an angler grinder and new plaster/stucco to fix it),
  • The foot print of the mount is too small,
  • The weight of the tv will pull the wall down

Hard facts:

  • Aerated concrete wall: 8cm thick
  • TV weight: 35kg
  • Mount arm length: 45cm
  • Mount wall size: W=6.5cm H=25cm

I'm not planning on having the tv at full arm extension, but the GF is worried about the worst case scenario of someone pulling it out and the stress will cause the wall to break and come down. Or even the mount coming lose and wrecking the TV.
So It seems like the best case scenario is to drill through the wall and put a back plate in, sandwiching the wall between the plate for the wall mount and the back plate with metal bolts holding it in place.

So I guess I'm looking for advice on:

  1. If this idea is crazy?
  2. How thick should the back plate be? Is a 1cm wooden block enough?
  3. Do I need a front plate to increase the surface area from the wall mount?
  4. If I do need a plate how thick should it be to not just bend? is 2mm aluminum thick enough?

I've spent a day trying to research and worrying about all the parts. Any experience you guys have would be awesome as I've not worked with these blocks before.

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Comments

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Spinaccio t1_j9ulidv wrote

Toggle bolts for this. https://www.lowes.com/pd/TOGGLER-10-Pack-Assorted-Length-x-1-4-in-Dia-Toggle-Bolt-Drywall-Anchor-Screws-Included/3183831 Yes, they work in concrete as well.

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jacobjkeyes t1_j9uo9wk wrote

If I know for a fact that I'm dealing with Hollow concrete block or similar, I will definitely prefer toggle bolts. Tapcons also work but toggles will always be more secure even though they require a lot more Drilling

You can probably rent a hammer drill from your local hardware store and they may even include the appropriately sized masonry bit to make the hole.

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GrimResistance t1_j9vke7p wrote

A regular drill will easily drill a ½" hole in a concrete block, hammer drill isn't terribly necessary. Yes on the masonry bit though.

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T3zcat OP t1_j9vou13 wrote

Thanks for the suggestion, I will say that from the experience I've had so far the aerated concrete is very different from actual concrete.

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Spinaccio t1_j9vw1dh wrote

The ones I linked are actually advertised for drywall. If there’s space behind your concrete I’d think they would be fine.

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