Ever try to hang a heavily-framed picture with a small brad nail, only to come home and find it has fallen to the floor? Or worse...you installed shelving, piled on the books, then watched them fall, ripping a hole in the drywall? Although fasteners initially feel like they have adequate holding power, over time the weight of a load causes tension and stress upon the material they were installed into, or upon the fastener itself.
Unless you're hanging something excessively lightweight, plastic anchors are a poor choice for most jobs. "Economy" anchors are typically included with kits as a courtesy. Avoid them. Better quality anchors are only slightly more expensive. Choose according to the material you will be adhering to as well as the weight of the item you want to hang – weight limitations are listed on packages. When in doubt, use an anchor that exceeds the weight of the item you're hanging. Look for brands with more ribbing for the greatest holding power.
There are two main types of anchors
Expansion Type: Used for concrete, brick, metal or dense wood, these anchors expand as a screw or bolt is threaded into them. These are terrific to use when installing shelves on basement walls.
Hollow Wall Type: Designed to be used in thin materials (specifically, hollow core doors) or hollow-walls. Once installed, they cannot be pulled back through the installation hole. Before installing, drill a small hole the same size as the anchor, then tap the anchor level with the surface before screwing object into place.
Choosing the right anchor for the job
Threaded drywall anchors are a perfect choice for drywall and although they come in both plastic and metal, metal is more durable and extremely easy to install. Make a small starter hole in the exact spot you need to hang something, and then screw the anchor in using a Philips-head screwdriver until the anchor is flush with the wall.
Use threaded drywall anchors for: Lightweight shelving, wall-mounted light fixtures, smoke alarms, doorbells, heavy pictures with flat-mount hooks, wall-mounted mirrors.
Molly bolts are an expansion anchor very easy to install by drilling a hole the diameter of the molly (for larger sizes) or by using an awl or punch (for smaller sizes). Tap the molly into the hole making it flush with the surface of the wall. Screw clockwise, until you feel the metal teeth of the molly pull it tight, locking it into place.
Use molly bolts for: Towel racks, light to heavy duty shelving, curtain rods, wall-mounted mirrors.
Hollow-core door anchors are made specifically for hollow-core doors of all types, holding light to heavy loads depending on size. These install like molly bolts.
Uses hollow-core door anchors for: Towel racks, lightweight shelving only, wall-mount mirrors (with clips).
Toggle bolts are reserved for big jobs – they are the best hollow-wall anchors if you want a guarantee a heavy item isn't going anywhere! Made up of both a bolt and a "toggle" which is a pair of metal spring-loaded wings, the rule of thumb is simple: the larger the diameter, the stronger the toggle. Longer bolts are used for thicker walls, so choose the appropriate length of bolt as well as diameter. Installation requires boring a hole in the wall large enough to accommodate the toggle so choose carefully or you'll end up with a hole larger than you need. Uses for toggle bolts: Heavy curtain rods and sconces, heavy shelving, towel racks.
Professional tip: Lightweight loads are 10 lbs. or less; medium loads are 10 – 25 lbs.; anything over 25 lbs. requires a heavyweight fastener.