I installed a floating shelf in my living room using the plastic anchors that came in the box. It held up three picture frames for about two weeks. Then one morning I heard a crash that sounded like someone had thrown a chair through a window. The shelf had ripped clean out of the wall, anchors and all, leaving craters in the drywall the size of golf balls.

Drywall is basically compressed gypsum powder wrapped in paper. It has almost no structural strength. A screw driven directly into drywall can hold maybe ten pounds before it pulls out. The plastic anchors that come with shelves claim they hold fifty pounds. They are lying.

Here is how to install a shelf that actually stays.

Option 1: Hit a Stud

This is the best option — screw directly into a wall stud. Wood studs hold hundreds of pounds per screw. Find them with a stud finder or the magnet trick: a strong magnet will stick to the drywall screws underneath the paint. Those screws are driven into studs.

Studs are spaced 16 inches apart in most US homes. If your shelf brackets do not line up with studs, you can screw one side into a stud and use a heavy-duty anchor for the other side. One stud is better than zero studs.

Option 2: Toggle Bolts

If studs are not where you need them, toggle bolts are the next best thing. You drill a hole through the drywall, insert a spring-loaded metal wing, and it opens up behind the wall — clamping the drywall between the bolt head and the wing. A single 1/4-inch toggle bolt in 1/2-inch drywall holds about 100 pounds in shear (downward force).

The downsides: the hole has to be big enough for the folded wing to pass through (usually 1/2 inch), and once installed the bolt cannot be removed without losing the wing inside the wall.

Option 3: Molly Bolts

Molly bolts — also called hollow-wall anchors — are the middle ground. You drill a hole, tap the anchor in, tighten the screw, and metal legs expand behind the drywall. They hold 50-75 pounds each in 1/2-inch drywall and can be removed more cleanly than toggle bolts.

The key with molly bolts: you need a setting tool or you will just spin the anchor in the hole without the legs expanding. Most packs include a cheap plastic tool. It works. Use it.

What Never to Use

Plastic expansion anchors. The ribbed cone-shaped ones. The ones that come in the plastic bag with your shelf. They are rated for 20-50 pounds in shear — in perfect conditions, in 5/8-inch drywall, installed perfectly. None of those conditions exist in real life. Throw them away. Buy toggle bolts instead.