Yet another wall mount TV with metal studs question

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Old 12-31-08, 02:10 PM
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Yet another wall mount TV with metal studs question

Hi folks,

After doing quite a bit of reading online, I have, of course, come to many different opinions about this subject.

I have a Sharp 42" LCD TV that weighs 48lbs without the stand, and a Sanus VMSA (Silver) wall mount that extends up to 9.5" away from the wall, tilts, rotates, swivels, etc. The mount accomodates televisions between 30-50" and up to 150lbs in weight. The mount is approximately 28lbs in weight.

We have metal studs here in our apartment building and 5/8" drywall.

So working with a total of 76lbs of weight, I went to Toggler.com and used their tool that they have, and put in the following criteria:

Application Type: Wall Mount
Wall Type: 5/8" Drywall
Weight: 701 to 800 lbs ( going with 10 times the weight for safety? )
Distance: 7 to 12 in
Number of anchors: 8

Toggler says that the 3/16, 3/8, 1/4, and 1/2 will all work for this application. Fastenal only had 10 packs of the 1/4" available, so I have them on order.

My idea is thus:

The wall-mount bracket is about 12" tall with room for 4 anchors.

I get a piece of 3/8 plywood cut to be 16 or 18" wide and make it tall enough so that I can put one extra anchor in to the stud below the wall plate, and two anchors above it, so 5 on each side, 10 total. I am going with the extra one above the wall mount instead of below because as I read this is where the most force and different kinds of force are being applied. The plywood would be mounted on the outside of the wall, as aesthetics are virtually irrelevant to us, we just want the tv up off the ground so our child doesnt pull it over on herself or try to climb the stand that is there.

The result should be something like this (apologies for the mspaint):



Some people have suggested cutting the drywall and inserting like.. a wood crossbeam or something (pardon my verbage, this is my first foray in to DIY anything save for computer and car stereo stuff) and then anchor to that. Others have explicity said the only way to do this is to take the wall apart and reinforce the steel studs with wooden ones that run the entire height of the steel one. That seems a bit excessive for 76lbs and a lot of advice seems to be from when plasma tvs weighed 120lbs themselves before the mount.

So aside from 'is this ok?' my other question is, I noticed when drilling in to the wall to see how thick it was and so on, that the steel stud seems to be spaced away from it, not entire flush with the drywall. Is that normal? I thought it would have to be flush because of the drywall being anchored to the studs?

Edit: The wall in question is the wall that partitions our living room from the second bedroom. There is nothing going to be mounted on it on the other side.
 
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Old 12-31-08, 03:37 PM
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unfortunately you have found the Achilles heel of steel studs, that being their not having much holding strength. I would go with at least 1/2 in ply and large enough size to have fasteners equal to the weight needed, no closer together than 4 in spacing on the fasteners. the togglers you are looking at are not rated for steel studs, don't plan on just drywall holding this load. you need to find a fastner rated for steel studs.

life begins when the kids leave home and the dog dies
 
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Old 12-31-08, 05:06 PM
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Hello,

Thank you for the quick reply.

I think I understand what you are saying, however it confuses me because if you take a look at:

http://www.toggler.com/pdf/toggle.pdf

You will find: "The SNAPTOGGLE anchor is a heavy-duty hollow-wall anchor for use in walls, ceilings, or floors of
materials such as gypsum board, drywall with a
steel stud
"

In addition to that, still on the first page, within the "UTLIMATE TENSILE PULL-OUT VALUES" section, the "BB" Anchor (1/4"-20 which is what I ordered) has two listings for 1/2" and 5/8" drywall with 25 gauge studs.

Furthering my confusion, the 1/4"-20 BB series anchors are listed here:

Parts Express:TOGGLER BB 1/4"-20 Heavy-Duty Wall Anchors w/Bolts 10 Pcs.

as being good for up to 265lbs to anchor HDTV 'without studs' -- of course I plan on using the studs..
 
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Old 04-19-09, 12:36 AM
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Hi there, I am coming across the exact situation you faced earlier in mounting a tv with metal studs. There is a 1 inch space between the 5/8 drywall and the metal stud. I wonder how this extended allocation of weight will affect the load capacity of the anchors.

What did you finally decide on doing with your situation? Those snaptogglers seem strong enough on drywall alone, so I'm seriously thinking of just using them (well lots of them).
 
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Old 04-19-09, 10:11 AM
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How can there be a space between the drywall and the studs?The studs are there in part to hold the drywall.Drywall is not self supporting.

At some point the drywall is attached to something maybe a stud you didn't look at.A stud that's there with nothing attached to it serves no real purpose unless it was placed there to hold some part of the plumbing etc.

Suggest you get a stud finder and track down how this wall is built.
 
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Old 04-19-09, 11:52 AM
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the could have used "hat channel" which is an additional member run horizontally. It is used for sound isolation. There is also a Z channel as well.

If that is the case, you could have problems since there is nothing directly behind the rock where the studs are except that channel. Not sure how far apart it was spaced though.

One thing everybody needs to realize though is the stress on such an install is mostly shear and not tensile. That means the weight is pulling down and not away from the wall. That is a bad thing in the case of the channel added wall though because you are depending on the rock to support the bolts rather than the tension between the front of the wall system and the back of it (the stud). They can become loose as the rock is rubbed away from movement from any vibration. You cannot make that type of installation tight because you will break the rock.

In such a situation, I would open the wall and install a board across the studs to fill the gap between the stud and the wall thick enough to set directly behind the rock. Then, I would use the togglers. It really won;t take as many as you think due to the type of stress involved.

If this is an apartment, I would STRONGLY suggest landlord approval before any installation.
 
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