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I'm doing earthquake preparations. I want to secure two large, heavy, freestanding shelving units that sit on the garage floor to the adjacent walls.

The shelves are pretty thick steel (with particle board shelves), so they're very heavy and large--guessing about 7-feet tall and about 7 feet long when assembled. About 20 inches deep. (The unit sits about 2-3 inches from the wall because of a protruding foundation that runs the entire periphery of the garage along the floor.)

We live in a condo apartment building with thicker drywall than I'm used to seeing and also steel 2x4s. I don't trust the 2x's alone to secure the units and I'm not sure about the drywall.

That said, my thought is to use a vertical 10" length of plumbers tape in two places, wrapping over the steel rim of the top shelf (between frame and wooden shelf), and secure each end of the tape to the drywall with a heavy-duty anchor, one above the shelf frame and one below, plus washers between screw heads and tape. (I'm NOT planning to anchor into the steel framing, just the drywall.)

**So two questions...

  1. I'm I trusting the drywall too much here? Should I be anchoring to the metal framing?

  2. If my plan is good enough, What size and kind of anchors would you recommend to attach the tape to the drywall...would molly bolts be enough or would you suggest using toggle bolts?

Apologies for the long question. I think you may need that level of detail.

Thank you!

Bill

BillCord
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    No, your plan is not a sound one and it's not possible to provide an answer with the limited information provided. What you need to do is get a qualified seismic engineer to evaluate your situation and provide specific guidance to mitigate the danger. – jwh20 Jul 23 '20 at 12:05
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    By "tape" I assume you mean steel strapping. That stuff probably doesn't have a lot of tensile strength, and part of the answer depends on what you'll be loading the shelves with. If it's teddy bears, go ahead. Otherwise, drywall will in no way be strong enough to restrain a bucking load. Even a few screws in the steel studs would yank right out. You need a distributed anchoring to many points in the framing. – isherwood Jul 23 '20 at 13:36
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    I would say your plan is a waste of time only anchoring to drywall , toggle bolts can hold a static load of a few lbs 20 or more no problem but as a sizemic anchor it will probably pull a large toggle right through the Sheetrock. Find the stud drill your hole the stud will provide hundreds of pounds restraint I say this with experience of building and repairing homes in California. – Ed Beal Jul 23 '20 at 13:38
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    At a minimum, I'd scrap the pip-hanger tape and go with earthquake strapping/anchors. A home inspection at sale time will definitely ding you on that, so you'd have to do it then. But, since this kind of shelving is probably going to go with you during the move, you're doing this for _your_ protection. Don't skimp out on protecting _your_ family. – FreeMan Jul 23 '20 at 15:06

1 Answers1

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I'm not an engineer, but I've built and destroyed a great many things in nearly half a century of living. Here's what I'd do.

  1. Fasten a continuous 2x6 to the wall behind the top of the shelving units. It should extend past each unit to the nearest stud, and it should be fastened to each available stud with at least two fine-thread construction screws.
  2. Secure each upright in the shelving units to the 2x6 with 5/16" eye bolts and a loop of 3/16" chain. Use threaded chain links to close the deal. They don't need to be tight. In an earthquake everything's moving somewhat anyway.

Plan view:

 _^_______________^_______________^______________^_____  <-- screw locations
|______________________________________________________| <-- 2x6 board
     *   *                                 *   * <---------- chain
     *|-|*                                 *|-|* <---------- shelving upright
     *****                                 *****
isherwood
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  • My concern with not snugging the chain up gudntite here is that you could get the shelf rocking in an earthquake, creating repetitive impacts that'd eventually damage or break the chain (it's why water heater straps need to be fitted tightly) – ThreePhaseEel Jul 23 '20 at 23:27