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I would like to install a 2-Post 12U wall-mounted server rack in my utility closet. The rack will hold up to 200lbs. However, my equipment will be just under 180lbs. Most of the weight will be at the last 4U of the rack (2-2U UPS Battery Backup units weighing in at 63lbs each)

I have two studs 16" apart that I can secure the rack to with 4 lag bolts included. However, my concern is not being able to hit the center of the stud and having the equipment rip off the wall.

Would ripping out the sheetrock and installing a 24" wide by 48" tall plywood board in its place be a better option? I could then mark the center of the studs once I see them and screw the lag bolts through the plywood first and then into the stud?

I could even add additional 2x4 going vertically and horizontally to strengthen the integrity of the wall.

Thoughts?

Specs of the wall-mount rack:

Weight (lbs): Approx 15.5
Size (in): 24.8 x 20.1 x 18.24 (HWD)

Here is a link to the actual rack

Image from linked website, to limit link-rot

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You can overkill the job as much as you like, but it's easy enough to use a studfinder or a magnet (looking for screw-heads) to establish the location of the stud non-desctructively, or drill some small holes that will be covered by the rack (and which you can spackle) to destructively identify for certain where the edge of the stud is, and thus infer the center. Given an inch and a half of surface, you don't have to be too precise not to miss the stud.

I've mounted dozens of wall-mount racks and never bothered with more than a studfinder and/or magnet, and not one has fallen off the wall.

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  • Even if the lag bolts are 5/16" diameter, you still have about half an inch leeway on either side of the centerline to keep the lag bolts fully in the stud. In other words, you have a 1 inch wide area in which to sink the lag bolt and be completely in the stud. I wouldn't worry about it. Use a stud finder and find the middle the best you can. – rjbergen Oct 24 '14 at 12:04
  • I have a stud finder but at times I've noticed I was off center. I like the idea of drilling small holes left and right to find the exact center. Thanks for the easy tip! – user1052448 Oct 24 '14 at 13:23
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You're mounting this inside a cupboard, so there's some flexibility for exploration.

Start by finding the studs using any way that works for you.

  • Studfinder - never had much luck with these personally
  • Knocking on the wall - this also routinely fails for me.
  • Magnet - get an old Hard drive magnet and slide it over the wall. You'll feel it pull when it goes over a nail/screw. Mark the spot and then search straight up/down for more. Note that the very top and bottom of wall have top/bottom plates, so nails in the edge 40mm are probably NOT studs.
  • Shadows - shine a bright light sideways on the wall and look for nail pops.
  • Wall plates - if there are any power sockets, ethernet plates, aerial outlets, or light switches on either side of the wall, you can pop the lid off and look inside. I use a thin plastic ruler to slide between lining and any insulation in wall, until it clonks into a stud. Mind out for power.
  • Identify existing fasteners into studs - look for big screws for shelf brackets etc.

Once you've identified a stud, drill into it with a thin drill bit - a 2mm or so. If it goes "drill... freespin" then you missed. If wood swarf comes out, then you got something. The difference in feeling is obvious.

If you missed , then grab a length of thin wire. Bend into a curve, feed into the hole, and swing it around. You're feeling for the stud. If you find nothing, stop and reevaluate.

Once you have two guaranteed studs, then measure the gap between them. Your next one should be that distance further down the wall. Depending on the age and location of your house, it could be 18 inches, 24 inches, 600mm centers.

Its also possible that near doors and windows, the studs are doubled up together for added strength. And sometimes a wall's length isn't cleanly divisible by the distance between centers, so sometimes there's a shorter gap.

Inconveniently, cupboards/wardrobes/closets tend to be too small for clean spacing of studs, so, good luck!


Now you have a wall, with studs identified and perhaps a few.... test bores.

You can generally wipe a little putty into the small holes and smooth them off, and then paint in a couple of days. Filling small holes is a lot easier than filling bigger holes.

If your space doesn't have enough studs, then made the spreader board go from wall to wall. This also helps if the rack's mounts don't line up with the studs conveniently.

You're aiming to hang a decent amount of weight too, so I'd suggest getting a spreader board / load board / backing board. A 25mm piece of customwood or stout ply would be ideal. Make sure its wider than your rack, and wide enough to span two studs. You can even run the board right up to ceiling level to catch the top plate - the bottom plate is normally behind skirting board and out of reach unless you remove that too.

Use plenty of decent lag bolts to secure the backing board to the wall via the studs. Use a lot of lag bolts to secure the rack to the backing board too, aim to fill every place in the rack that offers a screw-point.

If that's not enough, you can add stringers along the side walls to add bracing off the

The backing board also lets you add power points where you want them, and to lay out multi-boxes and wires neatly to avoid the ugly Rats-nest.


Personally I got a full-height 42U floormount cabinet used, and it works perfectly. When moving house we just carefully wheeled it onto a truck via the truck's tail lifter. Another option for you is to mount your UPS on the floor, perhaps on a platform to keep it off the concrete. Mine lives in the garage, which helps with ventilation.

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    Just curious, what is "customwood"? – FreeMan Jun 29 at 13:34
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    Got it. In the States, we'd call that particle board. – FreeMan Jun 30 at 0:06
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    and your "chipboard" is what we'd call "oriented strand board" - big flakes of wood pressed together in all sorts of random orientations (which makes the "oriented" part seem a bit... disorienting.) Yeah, terminology varies: lorry/truck, fries/chips, chips/crisps, biscuits/cookies. Can we agree that "plywood" is made from large sheets of veneer, shaved off a tree, then laid down at 90° angles? ;) – FreeMan Jun 30 at 10:40
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    @FreeMan sure can. Basically the idea is to spread the load of the rack over more than one stud, and to help if the holes aren't over a stud anyway. Server racks can get heavy, specially when lead acid batteries are involved. – Criggie Jun 30 at 12:50
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    I fully get the your answer (and voted for it), I was just curious on the "customwood" as I'd never heard that term before. And, now I'm out as we're getting yelled at for chatting... – FreeMan Jun 30 at 12:55

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