Studs are the vertical structural framing members located behind finished wall surfaces. During remodeling and other activities, it's sometimes necessary to pinpoint their exact location. For example, if you want to hang a shelf on a wall, it's generally best to anchor it directly to a vertical wall stud, especially if the load will be quite heavy.
In most homes, wall studs are upright pieces of 2-by-4-foot or 2-by-6-foot wood lumber that form the frame of the walls. In some residential construction—especially apartments and townhomes—the studs may be steel. Most people rarely need to bother with studs, but knowing how to find them is valuable when anchoring oversized picture frames and mirrors, bookcases, or other heavy items to the wall.
While there are some tricks to finding a wall stud, using an electronic stud finder is the easiest non-invasive way to locate a stud.
Types of Stud Finders
Commercial stud finders come in several types and in several price ranges, from a few dollars for the very simplest designs to more than $500 for multi-purpose scanners that will locate studs among their many other functions.
Magnetic Stud Finders
The first magnetic stud finders were little more than small plastic devices with a little magnetic bar suspended in a display vial. When the tool was passed back and forth in the wall, the magnet would jiggle when it passed over a nail or screw head holding wallboard to the stud. Those versions are still available, but most magnetic stud finders are now more sophisticated tools that have multiple magnetic sensors inside. As you pass the tool over the wall, a line of LED lights flash to indicate when metal has been detected.
A magnetic stud finder can be tricky to use, since nail and screw placement can be fairly random, and the tool can be fooled if it senses metal water pipes or metal ductwork instead of fasteners anchored into studs. With practice, though, most people are able to pinpoint the location of studs using this simple tool.
At one time, these little gadgets were the only real option, and then in the early days of the pricey electronic stud finders, they were the affordable alternative, costing just $5 or $10. Now, however, basic electronic stud finders start at about $15. This has now relegated the simplest magnetic stud finders to status as a backup tool when batteries fail on an electronic stud finder.
A broad survey of stud finders recommended the Franklin 710 Prosensor as the top magnetic stud finder. It sells for about $50 and includes live-wire detection capability. Much simpler versions such as the Stanley 47-400 start at about $6.
Electronic Stud Finders
The term "electronic stud finder" includes a variety of tools, all of which require a battery to operate. The first electronic stud finders were offered in 1977 by the Zircon company. Within the overall category, there are several subtypes, but in general, all these tools work by means of an internal capacitor that creates a magnetic electronic field that registers changes in density in the wall. To work accurately, these tools usually require some calibration. The simplest versions of this tool signal the presence of a stud with an LED light or audible beep, but some have a small LCD display screen. More sophisticated models are equipped with circuitry programmed with algorithms that can identify other objects behind wall surfaces, such as plumbing pipes, ductwork, or electrical wires. These tools are often marketed as "4-in-1" or "5-in-1" stud finders.
Edge finders: These are very basic electronic stud finders that prompt an LED light to signal as the finder senses the edges of studs as it is moved horizontally along a wall. With practice, you can be quite accurate about outlining studs with this tool. These tools now rarely cost more than $10 to $12.
Center finders: These are newer, more sophisticated tools that sense density over a wider area and emit a LED signal or audible beep when the tool reaches the center of a wall stud. These tools no start at about $15. More sophisticated electronic stud finders can also locate the presence of live electrical wires in the wall.
A recent evaluation of stud finders aimed at the professional building trades recommended the Zircon MulitScanner A200 as the best of the electronic stud finders. It sells for about $45. Another excellent recommendation is the Tavool TH250, which sells for less than $20.
Radar (Sonic) Scanners
Radar scanners are the latest development in scanner tools aimed at professionals. They are sophisticated devices that can scan walls and floors for all kinds of information; locating studs is just one function. These tools work by emitting radio energy pulses and evaluating the bounce-back signals through internal sensors. Not only can they be more accurate than simple electronic finders when it comes to locating studs, but they have quite sophisticated circuitry with algorithms that allow the tool to accurately identify electrical wires, plumbing pipes, heating ducts, concrete, and almost anything else behind wall or floor surfaces. They can even pinpoint the location of rebar within solid concrete walls. These tools usually have sophisticated LCD display screens that communicate the tool's information.
In one recent evaluation of stud finders for the professional building trade, the top radar stud finder was the Bosch Detect 150. It sells for more than $500, making it a tool most appropriate for building trade professionals. Other models start at about $250.