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A stud finder is good for, well, finding studs you can’t see. Knowing wherethose are is crucial so you can be sure to screw into them instead of just thedrywall when you’re hanging something heavy, like a mirror or a mount for,say, a flat-screen TV. But some stud finders have other features, too, likedeep scanning and AC wire detection. That doesn’t mean they always do whatthey’re supposed to. There’s a lot going on in walls, and it can be hard,despite advances in tech, for any device to parse it all and determine what’sa pipe and what’s a wire from outside of the wall. To test all the features,we put a selection of stud finders through their paces on a wall of our ownmaking, as well as walls in existing homes.
Read on for quick info on the best stud finders from our testing, then scrolldown for buying advice, use tips, and in-depth reviews.
The Best Stud Finders
What You Need to Know About Your Walls
Most studs are spaced at 16-inch intervals—find one, and the next stud shouldbe about that same distance in either direction. Changes in spacing usuallyhappen near the ends of walls or doors and windows. If your stud finder seemsto be picking up things between the studs, it could be detecting metal orplastic plumbing components, electrical boxes or wiring, or metal ductwork.Electrical wires usually run vertically on the side of a stud and sometimeshorizontally between outlets. Keep this in mind, and if there are lightfixtures, switches, and outlets on a wall, you can make an educated guess asto where the wires might be. And pay attention to where the kitchen andbathrooms are. Water-supply and waste pipes for the second floor are oftenfound in walls on the first floor, below sinks, tubs, or showers. Pro tip: Ifyour basement is unfinished, you can go down there to see on the ceiling whereexactly the pipes go up.
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Stud Finding Tips
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Don’t touch the wall with either hand while you’re using a stud finder—this can alter its readings.
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Some tools need to calibrate before scanning, so start away from switches, outlets, or light fixtures.
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Apply some painter’s tape over the area you want to scan. It’ll give you a surface on which to mark your findings without having to write on the wall.
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When you detect studs, objects, or live wires, mark them.
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And where you detect a stud specifically, scan above and below that point to make sure it continues to the floor or ceiling. Other readings, not at regular intervals, could be wiring, plumbing, or ductwork.
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Freshly painted walls may be difficult to scan for up to two to three weeks, due to the moisture in the paint.
Photo credit: Trevor Raab
The Bottom Line
Stud finders have their jobs cut out for them, given the many variables inwall materials and construction. While you may get definitive results in onecase, you could be left scratching your head in another. Take everything witha grain of salt, and use the stud finder in conjunction with the placement ofelectrical and plumbing fixtures to figure things out. Be careful aboutassumptions, err on the side of caution, and take your time.
How We Test
For our evaluations, we built a four-by-eight-foot wall out of commonmaterials: wood and metal studs; drywall; copper, black, pex, and PVC pipe;and non-metallic sheathed cable. Then we scanned the wall with each of thestud finders. All functioned as expected when it came to detecting the studs,but we quickly found that a number of them designed to pick up the location oflive AC wiring simply didn’t. We checked with product engineers and found thatsteel studs, metal pipe, and ductwork could impair live-wire detection. So wewent back to our test wall, removed the steel studs and metal pipes, and builta second four-by-four-foot wall to test only the steel studs. Again, studdetection went as expected, but the devices did only a slightly better job offinding the live wires. A couple did, however, manage better than the others.We also took the stud finders to two homes—one a mid-1800s house with lath andplaster, and the other a 1970s tract house—for real-world testing.
Photo credit: Trevor Raab
Bosch’s GMS120 is much more than a stud finder (though it did locate thecenters to within an eighth of an inch). It can also detect live AC wiring,metal objects, plastic pipes that are filled with water, and even rebar inconcrete. This Bosch unit has audible tones, an illuminated ring around thesensor area, and an LCD screen—and all three work in concert, guiding you towhat you’re scanning for. The ring turns red when over a stud, while thescreen provides live-wire alerts and displays a bull’s-eye to indicate thestud’s center. Though the GMS120 didn’t find wiring in our wall, it did pickit up fairly accurately in the test houses.
With nine sensors spread out over 5-inches, the ProSensor M90 accuratelylocated studs. In testing, when we encountered one, the LEDs over the stud litup to show its full width. The M90 was also wide enough to indicateddoubled-up studs when we scanned around door frames and windows. Overall wefound it simple and easy to use, and it reliably detected wood and metal studsunder ¾-inch-thick drywall.
For finding studs, things don’t get much simpler than The StudBuddy. Using it,we effortlessly located nails, screws, or metal studs by sliding it in an “S”pattern, back and forth on a wall. Two strong neodymium magnets caused theStudBuddy to snap to ferrous fasteners or studs when we got within about 3⁄4of an inch of them. Sliding it up or down quickly confirmed additional hits,and the location and direction of studs. We found it worked even better onmetal studs because fewer confirmation “hits” were required. The StudBuddy mayalso locate other ferrous metals in the wall, like ductwork or electricalboxes—so scanning to confirm stud orientation is important.
If you just need to find a stud, Craftsman’s Hi-Vis Stud Sensor will doexactly that. It’s simple and effective, designed to locate the edges of woodand metal studs. Pressing the button on the side, we slide the Stud Sensorslowly along the wall, keeping an eye on the indicator. When it lit up, wewere at the edge of a stud. That indicator stayed on until we passed the otheredge, then we slid the unit back over the stud to confirm and mark the edgesbefore pinpointing the center. In our testing, the tool consistently foundstuds under drywall up to 3/4 of an inch thick.
DeWalt’s DW0150 was consistent in finding stud centers, locating both wood andmetal equally well through both 1⁄2- and 3⁄4-inch drywall. An alert in theform of an LED arrow pointed toward the studs, and we found that travelingover the stud and then back until the DW0150 picked up the center was nearly100 percent accurate. (We’ll give DeWalt kudos, too, for including a window inthe center, which made marking stud centers with a pencil easy.) The devicealso detects AC wiring—it was reliable through a 1⁄2 inch of drywall but onlyintermittent under the 3⁄4-inch variety.
Zircon’s A200 is a powerful wall scanner, with three scan modes. In ourtesting, it found the studs, iron and copper pipes, as well as live ACelectrical wires in our wall. It was also very reliable and accurate,detecting studs and indicating their centers by projecting a red arrow on thewall. When we passed over live wires, the screen displayed an icon indicatingthe wires had electricity running through them. While using it in dedicatedmetal-scan mode, we found it easy to differentiate between metal plumbingpipes and wood studs. If metal studs were present, it was a little trickier,but knowing the stud spacing helped us sort things out. In deep-scan mode, theA200 didn’t pick up PVC pipes in the wall unless they had water in them Wewere able to differentiate between pipes and studs by toggling between studscan and deep scan. And the A200 presented all this information on itsilluminated screen.
Craftsman’s center-finding unit has LEDs to indicate scan status and guide youto the center of the stud—orange ones light up when you’re over the stud, andred ones indicate when you hit the center. Scanning slowly in one direction,past the center, and then back got us accurate results over 1⁄2- and 3⁄4-inchdrywall. The AC-detection mode was somewhat vague, indicating an area 3 to 4inches wide when it picked up wiring. But repeated passes allowed us todetermine the wiring’s path. In standard scan mode, the Craftsman located somecopper pipe, which was odd, but the pipe was too narrow to be a stud and thedevice never registered a center. Similarly, it detected black pipe in metalfashion. (Note that although it located the pipes, the stud finder couldn’t,nor was it designed to, identify them as such.) Still, these readings can helpyou identify other objects in the wall you may want to be careful around. ** **
Ryobi’s Whole Stud Detector lives up to its name. As we scanned our test wall,arrows on either side of the finder illuminated, indicating which direction wehad to move in order to find the stud center. When we reached the center, fiveLEDs lit up showing the full width, the arrows went out, and the center markerbutton lit up. That center marking button is handy, as we didn’t need to havea pencil handy to mark the studs—pressing the button left a small dimple inthe wall. Note that while we were able to detect studs in a lath and plasterwall, it was too hard and the marker didn’t leave a mark. We detected bothwood and metal with the Ryobi Whole Stud Finder under ½- and ¾-inch drywall.It also picked up an iron pipe but couldn’t tell us if it was a pipe or astud—however there was so much metal in that pipe, the stud finder lit upacross almost 4 inches, which would be a lot wider than any stud we’d expectto find.
The Bosch Wallscanner D-tect 150 is really a lot more than just a stud sensor.It’s a powerful, professional-grade tool capable of scanning walls and floorsfor studs, pipe, rebar, and live AC wires—using scan modes for drywall,concrete, deep concrete, wet concrete, metal objects, in-floor heating, andone that shows signal strength. Our scanning for wood and metal studs, as wellas AC wires, in standard walls wasn’t much of a challenge for the D-tect 150;it found all quite reliably. We had to scan concrete floors and masonry wallsto really delve into its capabilities. We found one of the more usefulfeatures was how detected objects appear on the LCD display. As you find theobjects, they show up at depths relative to the surface being scanned. Formost modes, that’s 3 inches, but in deep scan, it shows up to 6 inches. Wewere able to locate a defunct steel drain buried with 5 inches of concrete inour shop floor. Thinking of more ways to leverage the D-tect 150, we searchedfor a steel survey spike under the pavement at one test editor’s property.Since we didn’t know exactly where it was, it took almost 15 minutes to locateit, with some of that time spent waiting for traffic. We did, however, locateit. The D-tect 150 is not cheap, but if you need to regularly locate hiddenthings in walls and floors—made from a variety of materials—it can do the joband may be worth the price.
We noticed a large number of positive reviews on Amazon, so we decided to tryout the Tavool 4-in-1 Stud Sensor. And we’ll admit we were surprised. For themoney, it’s hard to beat. It features four scan modes: three for specificobjects (wood, metal, live AC wiring) plus one for deep scanning—all workfairly well. One thing we noted is that it could be inaccurate if we neglectedto wait for the calibration to complete after turning the unit on. As long aswe waited for the audible beep, it found stud centers and edges, within ¼ ofan inch. We like that it has a center indicator, which saves time making edgesto locate the center manually. In me-scan mode, we were able to detect copperand black pipe but without a center indication. We found the live AC wiredetection was not always reliable, with some misses along the wire path.However, because we had access to the back of the wall, we came to theconclusion that this had to do with wire depth—more than 2 inches from theface of the wall and. the wires were harder to pick up.
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