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Discussion Starter · #1 ·
I just moved to a new apartment and I it has 5/8th inch drywall with metal studs 16" apart.


I asked the landlord if I could open the wall to put bracing and plywood behind the drywall. He wasn't too keen on the idea, but said I could do whatever I want on the exterior.


I was thinking of getting a piece of plywood wide enough to cover 4 metal studs, so 50"x30" approximately. I could then affix the plywood with eight 3/8" toggle bolts one at the top and bottom of each metal stud going through the plywood, drywall and metal stud.


The wall mount could then be fastened with 6 toggle bolts in the center 2 metal studs going through the plywood, drywall and metal stud.


The plywood would be painted to match the color of the wall.


I figured dispersing the weight across 4 studs and increasing the effective surface area of the wall mount to the size of the plywood would be adequate.



For anyone with some knowledge or experience, does this sound like it would be adequate?
 

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First of all, metal studs are stronger, stiffer, and will support more weight than wooden studs. The only consideration is that you must use different fasteners, lag screws will not suffice.


I would use the exact number of fasteners that your wall mount specifies, but I would substitute 1/4 x 3" steel "toggle bolts" for the lag screws. Make sure that the holes are centered in the metal studs, and you will be A-OK. Assemble a suitable washer just below the bolt head before you insert the expanding wing section into the drilled hole.
 

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Quote:
Originally Posted by Brett19648 /forum/post/19546803


I was thinking of getting a piece of plywood wide enough to cover 4 metal studs, so 50"x30" approximately. I could then affix the plywood with eight 3/8" toggle bolts one at the top and bottom of each metal stud going through the plywood, drywall and metal stud. The wall mount could then be fastened with 6 toggle bolts in the center 2 metal studs going through the plywood, drywall and metal stud.....

Toggle bolts should never be used to affix anything to a metal wall stud. You have to drill the hole very large to get the toggle bolt's wings through. There are fasteners designed specifically for metal studs - seek them out - but metal studs don't give you a lot of material to work with.


You may not need to use an ugly painted slab of plywood if you can find the right fasteners. But i would be concerned that the cantilever effect of a fully extended arm mount might be too much strain on the fasteners as the weight of the TV and the steel arm will exert outward force on the upper bolts, where a flat wall mount exerts more of a sheer force on the bolts.


And if you do use plywood, some of the guys here have installed blind nuts on the backside of the plywood before affixing it to the wall, then bolting the mount bracket to the blind nuts.
 

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Just use the 1/4" x 3" toggle bolts I specified, which are also called 1/4-20 (1/4" shaft, 20 threads/inch). I bothered to give you the size because the ones I specified are installed in 1/2" holes, and a 1/2" hole will not excessively weaken a 1&3/4" wide metal stud. 1/4" toggle bolts are rated for 90lbs per fastener, four will support 360lbs, enough capacity for any HDTV and mount I ever heard of.


It is true that you can sometimes find special metal stud fasteners called "HILN" fasteners, and that Peerless includes them with their wall mounts. But the HILN fasteners also require a 1/2" hole and are also rated for 90lbs weight per fastener. They only offer convenience of installation versus standard toggle bolts, which hardly matters for 4 or 6 bolts.


DO NOT upsize the toggle bolts to any size greater than 1/4", which is the shaft size, not the size hole required. For example a 3/8" toggle bolt requires a 7/8" hole. According to most building codes, when you make a hole larger than 1/2", the stud must be reinforced.


Use a sharp drill bit and a stud finder to make sure you drill through the center of each stud. Then snug up the bolts with just enough torque to remove all the play between the mount and drywall. Excessive torque will crimp the stud and weaken it. I used 1/4"x3" toggle bolts to install cabinets in my garage which support hundreds of pounds of tools and paint and auto parts.
 

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 These are what I use at work all the time to attach grab bars. Surely that's a more critical application than a TV mount. The main advantages are they are installed before the screw (you can easily remove and re-install the screw) and the bar is one solid piece of steel instead of flimsy spring loaded sheet metal 'wings'.
 

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Discussion Starter · #6 ·
Ok, so I had everything set up to do the install today, but there was a snag.


Only the interior walls of the apartment are metal studs with 5/8" drywall.


The exterior walls of the apartment are brick with 1"x3" wood furring strips fastened to the brick, then the 5/8" drywall is drilled to the furring strip.


Any suggestions how to mount to this surface?
 

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One of our apartment buildings have that arrangement on the ceilings and I use the same anchors mentioned in my other post. You'll have to tip the 1/2" bit sideways (one direction only) like below to get the toggle part through. Then rotate it 90 degrees.




_______ _______

_______/ /_____
 

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One of our apartment buildings have that arrangement on the ceilings and I use the same anchors mentioned in my other post. You'll have to tip the 1/2" bit sideways (one direction only) like below to get the toggle part through. Then rotate it 90 degrees.


_______/ /_____
 

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For the 1x3's, treat the wall just as if it were a wooden stud wall. Use a stud finder, then make sure that you drill each hole for the lag screws to the proper diameter and depth - which requires that you have two different drill sizes, and measure each bit for the proper depth. First use the smaller bit and drill a hole 1/4" longer than the length of the lag screw less the head. Then use the larger bit and drill to the depth of the unthreaded section of the lag screw just under the head.


Failure to use the two different bits of correct size, or to drill to the correct depth, increases the chance that you will break off the head just as the lag screw is almost sunk home. This happens when the screw bottoms out in the hole, or because the unthreaded shaft binds in an undersized pilot hole (because you got lazy and didn't drill with the larger bit).
 

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Quote:
For the 1x3's, treat the wall just as if it were a wooden stud wall. Use a stud finder, then make sure that you drill each hole for the lag screws to the proper diameter and depth - which requires that you have two different drill sizes, and measure each bit for the proper depth. First use the smaller bit and drill a hole 1/4" longer than the length of the lag screw less the head. Then use the larger bit and drill to the depth of the unthreaded section of the lag screw just under the head.

I doubt that 1"long lags are going to hold it very well...

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The exterior walls of the apartment are brick with 1"x3" wood furring strips fastened to the brick, then the 5/8" drywall is drilled to the furring strip.
 

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Quote:
Originally Posted by olyteddy /forum/post/19559126


I doubt that 1"long lags are going to hold it very well...


I agree 1000 % I would not use lags in a furring strip over block, no way no how ! you will still need to use some larger toggle bolts and drill thru the rock then right on thru the block, forget about the fur strip as it will not suffice in this type of install. I do think there could be one problem you might find along the way, the block just might be poured solid meaning you will have to skip the toggle and go with anchors or sinches to fasten to the solid wall.

Edit* I know you said brick walls with fur strips but I think that would be to thin to be a normal structural wall , if you see brick outside it is probably fastened to Block and the interior would be block as well with 1 x 3 fur strips covered with 5/8 drywall, all is not lost you might find the fasteners needed and get the finished product in the end run.
 

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Discussion Starter · #13 ·
The apartment is a 1 floor of a row house originally built in the 1800's. It was renovated and turned into apartments around 10-15 years ago.


I bought six 4" x 1/2" expandable sleeve anchors...


My girlfriend's father runs a painting and wall covering contracting business, so when we move out I will be requiring his services...
 
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