By Jeanne Huber
For The Washington Post
Q: I want to hang heavy artwork made of 25 Moroccan tiles on a stucco wall in our screened porch. I don’t want to damage the stucco. Can I attach hooks to the molding along the ceiling and hang the artwork with wires? Or do I need to get a stud finder and attach some sort of picture hanger into the studs? Or is there another solution?
A: Hanging heavy artwork from crown molding would avoid making holes in the stucco wall, an appealing idea. But don’t do it. Crown molding is typically attached with 2-inch-long finishing nails. Not only are the nails relatively thin, but the heads are small. That makes them easy to patch and paint over. But finishing nails don’t hold well, so your heavy artwork — and the crown molding — could come crashing down.
Nails hold into wood because of the pressure that wood fibers exert as they bend against the shaft when the nail pushes in. The thinner or shorter the nail, the fewer fibers make contact so the weaker the connection. Plus, the nail’s head acts as a sort of clamp; the smaller it is, the less resistance there is to the nail popping out or slipping through the wood.
Adding to the nail issue is the nature of crown molding. Although it looks substantial, most crown molding is attached at an angle and is mostly hollow underneath, with only the top and bottom edges making contact with the ceiling and wall. It’s easy for an edge to split if a nail isn’t set just right. And these days, there’s no guarantee that the crown molding is even solid wood. Most newer crown molding, especially for indoor use, is a type of particleboard. It works fine for covering the seam between wall and ceiling, but it wouldn’t win a strength contest.
The best way to hang heavy artwork on a wall built with studs — whether the studs are covered with stucco, plaster, drywall or wood paneling — is with screws that bite directly into the studs.
Often, it’s possible to locate studs by tapping on a wall and paying attention to where hollow sounds turn to thuds. But that doesn’t work well on stucco. If you can see where nails hold the crown or baseboard molding to the wall, those generally also point to where the studs are. Or get a stud sensor — but use it on the interior side of the wall. Stucco typically has chicken wire or other metal mesh hidden underneath, to give the stucco something to grip. The metal interferes with the sensor’s ability to detect density differences within the wall. But by using the sensor on the interior side, you avoid that issue.
Mark the studs, then measure over to the door. Then transfer the measurements to the exterior side. Confirm the stud location by drilling a narrow, easy-to-patch hole and making sure it reaches wood. Be aware that newer stucco walls might have foam insulation over the studs, so you may need to drill a few inches deep.
Studs are usually 16 or 24 inches apart, measured from their centerlines. Once you know you’ve located the studs, switch to a bigger bit sized for more substantial screws. A masonry bit works best to get through the cement-based stucco, but switch to a regular bit for pre-drilling into wood.
How many screws? In part, this depends on how you hang the piece. Unless a stud happens to be where you want the center of the artwork or midway between two studs, consider getting an interlocking metal or wood hanging system, called a French cleat, so you can attach the wall piece where the studs are, then scoot the artwork back and forth until it’s centered where it looks best. Weigh your tiled piece and choose a system that’s rated for at least a slightly higher weight. Also factor in the thickness of whatever is behind the tiles so you don’t break them when mounting the hangers.
As a good rule of thumb for what length and thickness of screws to use to attach hangers to the wall, consider going with what installers use to hang upper cabinets, because these screws need to secure both the cabinets and what they hold. Typically, cabinet screws have wide, washerlike heads and are No. 8 or No. 10 width and 2 1/2 inches long, enough so at least half the shaft is in the stud after passing through the cabinet and drywall. If insulation is behind the stucco, you may need longer screws. Thicker ones are fine, too. Just don’t use drywall screws; they are too brittle and could snap.