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So I am going to mount a 65" tv weighing approximately 55.347lbs using an omni mount (probably this one: http://www.omnimount.com/products/tv_wall_mounts/full_motion/ulpc-x/). It supports a max 250lbs. The arm extends and tilts/pans/swivels and I plan on using that functionality all of the time.

My home is older and is framed with 2x3s. Assuming I follow the manufacturer's installation guide correctly, and I find the center of the studs correctly, can I go straight to the studs or should I think about 3/4" ply (VC) between the wall and mount?

I guess I'm just worried about 2x3 vs 2x4 and having the arm extended completely.

Any advice is appreciated.

Edit: I just saw that the power bridge product require a 2x4 depth. So that is out.

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    Although answers recommending more robust attachment methods are not wrong per se., you won't have any problem with screws into sound 2x3s. Even a single good size lag screw screwed 1 1/2" deep into sound wood could hold that easily, both shear and tensile. – Jimmy Fix-it Dec 14 '16 at 6:46
  • Are the 2 x 3 studs exposed in the garage or anywhere else so you could examine them? I have heard that studs were made of better wood 'back in the day'. I assume you would have no finger jointed studs. Where is this house located? Is this an interior wall? – Jim Stewart Dec 14 '16 at 17:58
  • It's an exterior wall in my living room, but the studs are not exposed in any way; the room is finished with drywall. – Mike Dec 15 '16 at 10:26
  • What is the treatment of the outside of this exterior wall? brick? wood siding? something else? The reason I ask is that depending on what length lag screws you use, the lag screws could pass all the way through the 2 x 3 studs and penetrate slightly into whatever is attached to the outsides of the studs. So if the 1/2" drywall plus 2 1/2" for the studs gives 3". If you put 3/4" plywood over the drywall the total would be 3 3/4". – Jim Stewart Dec 15 '16 at 20:27
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Looking at the manual, it looks like the top mounting points are about 1' above the bottom mounting points. If you have that 55 pound TV at the full extension of 2', then that means the top mounting points will be pulling directly out from the wall with double the weight of the TV, or 110 pounds. Guess that someone will lean on the thing, or your cat will jump on top, and you should plan for at least 200 pounds of pull on those anchor points (100 pounds per screw).

I doubt that a single screw in a 2x3 can reliably hold 100 pounds pull straight out from the wall. That, plus the info that you need a 2x4 cavity to use that power bridge, leads to the following suggestion:

  • Cut a 1/2" plywood panel large enough to support the base of the OmniMount, plus a few inches on all sides
  • Bevel the edges of the panel to make it look more planned/streamlined
  • Cut a hole in the middle of the panel for the power bridge, expecting to mount the bridge into the hole, rather than into the wall, so you have the needed extra depth
  • Cut a clearance hole in the wall for the power bridge
  • Mount the panel to your studs with plenty of 3" lag bolts
  • Mount the OmniMount to the panel
  • Mount the TV to the OmniMount

It's possible this is overkill, but wouldn't you rather be sure your lovely new 65" TV didn't become a YouTube-able lesson?

  • Would it be best to mount the plywood across three studs? So a piece ~35" wide to span 3 studs assuming they are framed 16" on center? Also, any reason not to go 3/4" with the ply? With respect to the lag bolts, I'm thinking 3 per stud - top, middle, bottom. Do I need to worry about mounting the bracket over the studs at that point or can it go on any part of the ply? If I mount the ply over 3 studs, I'm thinking of centering the mount over the middle stud. – Mike Dec 15 '16 at 10:31
  • Those all sound like good ideas, although you'd have to have the power bridge off-center (which, since it would be behind the TV, isn't a huge deal). – Daniel Griscom Dec 15 '16 at 11:21
  • I agree with Jimmy Fix-It's comment above. You are contemplating a much stronger mounting (if it's done right) than is necessary for a 55 lb TV. If you mount direct to the wall into two studs with four lag screws provided with the mount, you would have to insure that the screws in the kit would not be too long for your 2 x 3 studs. Possibly the screws provided would be OK even with your studs but you'd have to consider.I think each top screw would be under 55 lb tension (not 110 lb) because if total tension would be 2 times the weight of the TV this would be divided between the two top screws. – Jim Stewart Dec 15 '16 at 12:48
  • @JimStewart Yes, but that's if nobody ever touches or leans on the TV. In any case, your comment should be part of a new answer. – Daniel Griscom Dec 15 '16 at 14:57

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