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I recently purchased Granhult from IKEA for my wall shelf. The problem is that my wall stud do not align with the brackets because of the size of my shelf. Can I simply screw the bottom screws into the noggins and use wall anchors for the top screws? The shelf is going to hold books and some legos. Thanks in advance!

Granhult Wall anchor

popham
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TheCarpe
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  • Can you add plywood or 1x planks across the studs. One book not that heavy, but a bunch of books do get heavy. – crip659 Oct 15 '23 at 22:09
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    What are "noggins"? – popham Oct 15 '23 at 22:17
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    @popham Noggins are are 2x4s used to apply sense to heads, sometimes repeatedly. – crip659 Oct 15 '23 at 22:37
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    [Nogging](https://www.google.com/search?q=nogging), not [noggin](https://www.vocabulary.com/dictionary/noggin). – brhans Oct 16 '23 at 00:31
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    Either way it's UK English for blocking (noggin is also a synonym for block) – Jasen Oct 16 '23 at 04:42
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    @crip659 noggins are what 2x4s are bashed into so as to apply sense. (Noggin being a synonym for block, people with block heads need sense knocked into them.) – RonJohn Oct 16 '23 at 15:33
  • @popham noggin is foreign-speak for **dwang**, a common commonwealth term for the short horizontal nailed between studs. Locally there are three rows in a wall. You'll probably get a bunch more explanations with other weird-words for the same structural member - it may be worth asking a whole new question on the subject. – Criggie Oct 16 '23 at 18:21
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    In the unlikely even you could get away with using a single screw, how is it not obvious that should be the top screw, not the bottom? – Robbie Goodwin Oct 16 '23 at 23:24
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    If your "builder's intuition" tells you that the bottom screw is the important one, I suggest you hire professionals for all your construction work! – TonyK Oct 18 '23 at 13:44

4 Answers4

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No.

First off, the top screws take up most of the load. The weight of the shelf + stuff will try to pull the top screws out of the wall, the bottom screws comparatively hold very little actual load.

Secondly, why are your studs not vertical? I'm having trouble picturing why the bottom holes hit a stud but the top screws do not.

Books are very heavy and a shelf needs to be well built to hold them up. Your best bet is to get different brackets with larger vertical members, which reduces the bending torque the screws have to withstand.

Floating or floating-ish shelves are challenging because their fasteners are extremely highly loaded compared to traditional shelves.

whatsisname
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It sounds like you've found some horizontal blocking (nogging) typically designed to slow down the spread of fire.

At minimum attach the top of the bracket to the blocking since those will experience the greatest stress; Option 1 in attached image.

Even better would be to find a stud and get two screws into it and one into the blocking; Option 2.

Best yet would be to get a shelf which is as wide as your stud spacing and hit all four screws into a stud.

enter image description here

MonkeyZeus
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  • I agree with the last point. The OP himself says that the "size of the shelf" is the reason for the issue. – Wastrel Oct 16 '23 at 14:35
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    I was going to say "shorten the shelf till it lands on two studs" but never thought of getting a longer shelf. +1 – Criggie Oct 16 '23 at 18:23
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The bottom screws are there more to keep things aligned. The top screws carry the load, where the weight on the shelf gets amplified because of the short distance from the top screw down to the very bottom of the bracket. The worst case load amplification looks to be about 300% at one top screw (when all of the load is located at the tip of a single bracket). For something small like this, I would take 300% of the weight you expect and multiply it by a safety factor. I would shop for drywall fasteners that claim to hold this load in tension. It's a pullout load, not a shear load.

Often times when I design something, I'll imagine what would happen if some idiot decided to climb up and jump on, say, my arched trellis, and I'll treat that idiot as the expected load instead of climbing roses. Those brackets look flimsy enough that somebody probably won't try sitting on your shelf, but if you have a pet chimp, then consider anchoring to support the chimp weight instead of the weight of your books.

* For comparison, the AWC connection calculator outputs the withdrawal strength of a #8 screw with 1-1/2" embedment (2" minus a half inch of drywall) at 117 pounds for Doug Fir studs. For 1" embedment (1-1/2" minus a half inch of drywall), it's 78 pounds.

popham
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  • So you visit sites like Darwin awards and hold my beer? – crip659 Oct 15 '23 at 22:33
  • @crip659, there exist beefier drywall anchor than you're probably used to seeing. "Bullfix anchors" on Amazon come to mind. That and the shelf is 5" deep and 12" across. I _will_ qualify the answer better for small stuff like this, although I thought that the "chimp" bit was a pretty good caveat. – popham Oct 15 '23 at 22:37
  • @crip659, and the analysis is predicated on an absurdly conservative load distribution. If you can find a drywall wall anchor that claims to hold the 300% plus safety factor, then use it and you're good. – popham Oct 15 '23 at 22:45
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    "if you have a pet chimp" -- Every parent of a toddler has one of these. – Wayne Conrad Oct 16 '23 at 19:16
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Another option would be to find two verticals, and cut the shelf width so that the brackets aligned with them. Or at least use one upright for one top fixing, and an expanding plasterboard fixing for the other, which will spread out behind the plasterboard. They actually use a setscrew rather than a 'woodscrew', so present a much larger support area behind.

As already mentioned, the top fixings are the weight bearers, so they need to be the stronger ones, but without knowing exactly where the fixings will be compared with the noggins, it's difficult to give a more helpful answer.

Tim
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