What's the strongest anchor for something heavy in double drywall?

Question

I have a party-wall in my apartment-née-condo that seems to have two sheets of drywall installed against eachother. All attempts to find some sort of stud or resilient channel / furring strip have failed miserably; short of going Hulk and tearing out a hole large enough to stick my head in and look for studs, I've given up. (And I don't have the drywall-repair skills to seriously do that; if it can't be repaired with spackle, I'm not going to try it.)

I've looked at quite a few anchors; but most (toggles, mollies, and the like) of them seem to assume a standard(?) 1/2-inch thick sheet, or so. All the ones I have certainly do. I don't want to fall back on using plastic-expansion plugs, if I can avoid it; I hear they're extremely unreliable.

Does anybody know if high-shear-capacity drywall anchors exist that latch onto double-thickness drywall? Or have other advice for me?

(For context: I'm installing a large shelving system, that should ideally be able to support quite a bit of weight.)

Answer 1

It's not unusual for the wall between tenants to be made with an extra layer of drywall. The Snaptoggle will work in those walls:

It will easily handle the thickness you're dealing with, and it's easier to work with than regular old fashioned toggles.

Answer 2

I think this question warrants an answer with a healthy dose of caution:

Shelves for supporting a lot of weight should not be supported via drywall! Structural shelves need to be supported by proper framing...namely the studs within the wall.

Given that there is a party wall, if this is a condo, the walls may very well be made using steel studs. Depending on the gauge of steel studs, they may be able to support a wall shelf system, but maybe not.

The other issue is that you shouldn't put holes in party walls without permission. A party wall is shared property and your lease or title likely has some conditions pertaining what can and can not be done to a party wall on your own.

The two main reasons to be cautious is fire codes (the double sheetrock is to meet shared wall fire codes and putting a hole in it defeats that) and sound (ideally, the party wall is fairly soundproof between units...creating holes, as well as attaching items to framing will allow more sound transmittance).

Suggestion:

Consider a floor-based shelving system. Many of the wall shelving systems on the market also have the option to convert them to freestanding. Ikea's system, for example, can be installed with feet to make it freestanding:

Answer 3

I'm not sure what the big problem is with using a basic toggle bolt. All you would have to do is buy a longer bolt for the double thick dry wall.

Answer 4

EZ anchor is for sale at Home Depot, Lowes, Ace Hardware. These are rated for 50 pounds. Stanley Supply online also has these. If you can determine the width of your dry wall: it should be 1/2 + 1/2 or 5/8 + 5/8--then your anchor should be a length of 1 to 1/4 inch. If your shelves are not subjected to movement the anchors should hold well. You can also supply wood stripping on top of the drywall and at least get those to anchor into the stud positions. Wood strips would be the width of the opening (closet opening). If these do not match your anchor positions (if these are predetermined by your shelving) then you can go vertical strips. What is the width and height of your closets.

Answer 5

Well if you ask me there are two possible approaches: If you insist on mounting shelves onto the wall you can do following: cut part of the dry wall from top to bottom in two places. I’m sure that there is some metal construction inside, and then add vertical elements specially designed for load bearing. Knauf and other call it "AU profile”. They look like standard sub construction for drywall except the fact that they are made out of steel and are a bit bigger. Then you just put them inside dry wall and connect them with horizontal elements, preferably both on the bottom and top of the wall. In order to connect them use specialized elements which are "L" shaped. Then just put new dry wall on the places where you made a holes and that's it.
Other solution is different approach but, if you ask me far more easier and elegant: shelves construction can be completely separated from wall; what I want to say is that shelves are not mounted on the wall (in load bearing sense) but it has its own load bearing elements and it is just placed on the wall. If you have additional questions don't hesitate to ask.