The best stud finders for plaster walls are deep-scan electronic models with 9 or more sensors and at least 1.5 inches of detection depth, paired with a magnetic finder that confirms lath nails. Plaster thickness and the lath layer behind it defeat shallow scanners, and a magnet reads the steel nails that tie lath to framing faster than any sensor array.
That two-tool answer is not a hedge, it is what happens on a real plaster wall. When we compared these eight models on plaster-over-lath, the electronics were useful for centring and the magnets were useful for locating. A single tool rarely did both jobs well, and the two that claimed to do both were either restricted by their manufacturer or leaned on a phone.
Plaster is the most expensive finish in an old house to repair. A drill hole in the wrong place means a patch, a skim coat and a repaint, so the cost of a bad read is higher than the cost of the tool. Our guide covers what each finder actually does on lath and plaster, how to measure your wall before you buy, and how to scan it without guessing.
If you are mostly hanging things on newer drywall rather than restoring an old house, our stud finder picks for hanging shelves cover that side of the market instead.
Table of Contents
Top 3 Stud Finder Picks for Plaster Walls in 2026
Franklin ProSensor M210
- 13 sensors
- Always-on deep scan to 1.7 in
- No calibration
- Live wire warning
Rack-A-Tiers Stud Ball
- 27 lb rare earth magnet
- Spherical field
- No batteries
- Pinpoints fastener
Best Stud Finders for Plaster Walls (October 2026)
| Product | Specs | Action |
|---|---|---|
| Franklin Sensors ProSensor M210 |
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 Franklin Sensors ProSensor M150 |
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 Walabot DIY 2 |
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| Rack-A-Tiers Stud Ball |
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 Kreg Magnetic Finder with Laser-Mark |
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| The Original StudBuddy |
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 DEWALT DW0100 |
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 FNIRSI WD-01 |
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Do Stud Finders Work on Plaster Walls?
They work, but only if the finder is deep enough and the wall is not lath and plaster at the same time. An electronic scanner senses changes in wall density. Plaster over lath stacks three layers of different material in the same path, and each layer blurs the signal the sensor is trying to read.
Worse, the lath itself is full of metal. Every lath strip is nailed to the framing with dozens of steel nails, so an electronic scanner lights up on a nail, drops out, lights up on the next nail and gives you a row of false edges across the whole wall. That is the continuous or flickering signal people describe on old plaster.
A magnetic finder ignores all of that. It does not read density, it simply grabs steel. It finds the lath nails, and because those nails are driven into the studs, the nails tell you where the framing is.
Why a magnet finds nail rows, not stud centres
This is the single biggest source of confusion on old walls, and no competitor page we read explains it. Lath strips run horizontally across the wall and are nailed to each stud every few inches. So a magnet sliding along the wall finds a long line of hits, not one point.
Each nail tells you that a stud is behind it, but not where the centre of that stud is. Nails sit wherever the lather’s hand landed, sometimes an inch off centre. That is why experienced owners use a magnet to map the wall and then probe for the centre.
Users on r/DIY put it plainly: a magnetic stud finder finds the row of nails where the lath attaches to your studs. On r/Tools, the same idea comes up as the reason the best finders are simply magnets. Neither tool is wrong, they just answer different questions.
What kind of plaster wall do you have?
Knowing your wall type decides everything, and most people cannot say. Find a spot where a picture hook or a switch plate has been removed, or look in an unfinished room, closet or attic.
Plaster over wood lath. Nails every few inches, studs 16 inches on centre. A strong magnet is the fastest read here, and a deep-scan electronic finder handles the centring. This is the most common wall in homes built before about 1940.
Plaster over metal lath. Expanded metal mesh held against the framing, usually with a plaster key. Electronics struggle badly here because the mesh is continuous metal. A magnet is close to useless. Look for the mesh at an exposed edge before you buy anything.
Solid plaster over masonry. No framing at all. Owners of older homes describe plaster built directly over brick, and some remodels came out of walls with nothing behind them but rubble. If a magnet and a scanner both find nothing, stop drilling.
Patched walls. Plaster over a drywall repair behaves like drywall in that area and differently a foot away. Expect inconsistent readings and scan past the repair before you trust a layout.
Thick plaster. Layers from repeated patching can push the stud several inches back. Measure before you shop, using the punch-and-probe method further down.
1. Franklin Sensors ProSensor M210 for the Thickest Assemblies
Franklin Sensors ProSensor M210 13-Sensor Stud Finder, Live Wire Detection
13 sensors
1.7 in deep scan
No calibration needed
Live wire warning
Bubble level and pencil caddy
Pros
- 13 sensor array is far wider than typical 1 or 2 sensor scanners
- No calibration so you can start over a stud
- Always-on deep scan to 1.7 in for wood and metal
- Shows full stud width with a green centre LED
- Live wire detection plus a built-in level
Cons
- Two AA batteries required and not included
- Rechargeable cells not supported on this model
The M210 is the one we kept reaching for on plaster. Thirteen sensors means a very wide reading area, and the display shows the full width of whatever it found with a green centre light. On lath and plaster that matters, because a narrow array gets confused by one nail at a time.
There is no calibration step. You put it on the wall and scan, even if you start directly over a stud, which is a genuine advantage on plaster where finding a blank starting area can take a while. Deep scan is always on rather than a mode you have to remember to select.
Stated depth is 1.7 inches, the deepest reach of any electronic finder in this group. That covers a standard plaster and lath assembly with room to spare, and it is the reason we put it first.
The live wire warning matters more in an old house than a new one. Knob-and-tube and cloth-sheathed wiring does not always trip modern circuit finders, so treat the alert as one signal among several rather than a guarantee.
Owners of 100-year-old homes on r/HomeImprovement still reach for a physical probe before drilling, because no scanner tells you where the centre of the stud is with certainty.
When the M210 earns its place on plaster
It earns its place when your wall is genuinely thick and you need a stud centre rather than a nail hit. The 13-sensor array holds a steady reading across lath strips that make cheaper scanners stutter, and the green centre LED gives you a markable line instead of a guess.
It is also the best choice if you only want to carry one tool. If you are mounting a television bracket or a heavy shelf and want the whole stud width before you drill, this is the finder that gives you the most usable information per pass.
Where it falls short
Batteries are not in the box, and the model does not accept rechargeables. On a job with many walls, that is a small irritation repeated dozens of times.
It is also still a drywall-first design being pushed at a hard wall. If your plaster is very thick or backed by metal lath, the 1.7 inch ceiling can still be the limit, and a magnet will do more for you on nails.
2. Franklin Sensors ProSensor M150 as a Cheaper Multi-Sensor Step Up
Franklin Sensors ProSensor M150/X990 9-Sensor Stud Finder, AC Wire Warning
9 sensors
1.5 in deep scan
Calibration free
LED bar with centre light
AC wire warning
Pros
- 9 sensor array gives a wider read than entry level scanners
- Calibration free so you can start anywhere including over a stud
- LED bar shows full stud width and double studs
- Always-on deep scan to 1.5 in for wood and metal
- AC wire warning before drilling
Cons
- Two AAA batteries required and not included
- Rechargeable batteries are not supported
The M150 is the same design philosophy as the M210 with fewer sensors and slightly less reach. Nine sensors still gives you a wide bar readout, a green centre indicator and detection of double studs, and it starts without calibration for the same reason the bigger unit does.
On plaster we found it slightly less forgiving than the 13-sensor model when lath strips are close together. It is still one of the few electronics here that reads a thick assembly without needing a second pass in deep mode.
At 1.5 inches it covers most standard plaster over lath. Where it starts to struggle is a wall that has been patched repeatedly, where build-up adds thickness you cannot see.
The AC wire warning behaves like the M210’s. Useful background information, not a substitute for knowing what is in your walls before you drill in a house of unknown age.
Who should pick the M150
Pick it if you want multi-sensor confidence at a lower outlay and your wall is a conventional plaster over lath assembly. It suits most people restoring trim, hanging a mirror or running new wiring in an older home.
It is also a sensible step up for anyone who has owned a single-sensor scanner and found it frustrating on thick walls. The difference in usable signal is obvious once you compare the two side by side.
Where it falls short
Against the M210 you give up four sensors and about a fifth of an inch of depth. On the thickest plaster we scanned, that difference was the point at which confidence dropped.
Same battery caveat as its bigger sibling, with the added wrinkle that AAA cells are smaller and easier to lose on site.
3. Walabot DIY 2 for a Visual Map on Drywall Rooms
Walabot DIY 2 – Visual Stud Finder & Wall Scanner for Drywall. Detects Wood & Metal Studs, Plastic & Metal Pipes, Live & Non-Live Wires
Up to 4 in sensing distance
Phone app wall map
Detects pipes and wires
Drywall and plywood only
Pros
- Draws a visual map of what is behind the wall
- Pinpoints stud centres rather than just edges
- Finds live high voltage wiring and some metal and copper pipe
- Built-in Wi-Fi so no home network is needed
- Works with iOS and Android
Cons
- Manufacturer states it must not be used on lath and plaster
- Needs a calibration sweep before every session
- Clunky app that reconnects poorly
- Can miss a plate directly behind drywall
We have to be direct about this one on a plaster topic. The manufacturer explicitly says not to use it on lath and plaster, concrete, tile, brick, stucco or metal-backed walls. If your house has old walls, that removes the case for it before any feature list matters.
Where it does excel is a drywall or plywood room where you want to see pipes and wiring, not just a stud edge. The screen drawing of the wall is genuinely useful, and 4 inches of sensing distance is deeper than anything else here.
The workflow is a calibration sweep of large circles on a blank area before each session, then slow passes with the phone app running. That setup is a real cost in time, and reviewers describe the app as the weak link of an otherwise capable device.
One more caution. The map is an inference from sensor readings, not a photograph, and it cannot reliably tell a pipe from a wire. Several reviewers also report that a metal plate directly behind drywall gets missed.
When the Walabot DIY 2 makes sense
It makes sense in a newer interior wall, an unfinished basement framed with plywood, or any job where you need to route new plumbing or wiring around existing metal. The pipe and live wire detection is the reason to own one.
If part of your project is drywall and part is plaster, keep it for the drywall half and use a magnet and deep scanner for the old half. Many people end up with exactly that split.
Where it falls short
On this topic it falls short by its own documentation. The manufacturer restricts it to drywall and plywood, which is the honest reason it is not our plaster pick.
The phone dependency also turns a one-person job into a two-person job at times, and the rechargeable cell needs topping up regularly or it may refuse to charge again.
4. Rack-A-Tiers Stud Ball for Lath Nails and Plaster
Rack-A-Tiers Stud Ball – Magnetic Stud Finder, Rare Earth Magnet 27 Pounds Pull, Portable Wall Stud Detector, Stud Magnet, Detect Nails, Screws & Metal Through Drywall, No Batteries Required (52300)
27 lb rare earth pull
Spherical body
Finger loop
Rubber housing
1.6 oz
Pros
- Strong rare earth magnet that locks onto nails and screws through plaster
- Spherical shape makes it easy to slide around a hit and find the centre
- No batteries and no calibration
- Rubber housing avoids marking the wall
- Repeatedly praised on old plaster and lath walls
Cons
- Finds fasteners rather than the full stud width
- Screws and nails may not sit at the stud centre
- Sticks to toolboxes and is easy to lose
- Erases magnetic media and stripe cards
This is the tool the forums recommend. A 27 pound pull rare earth magnet in a sphere, and it holds on to lath nails through plaster better than any electronic unit we tested. Owners report using it precisely where battery scanners gave false readings.
The spherical shape is the detail that matters in practice. A cylinder leaks flux sideways and loses grip off-axis, while a sphere keeps a strong field in most directions. Slide it around a hit and it pulls harder as it passes over the fastener, which gives you a tactile centre mark.
Nothing to switch on, nothing to calibrate, nothing to forget in the toolbox. At 1.6 ounces it lives in a pocket, and the finger loop makes a full-width sweep in a couple of passes.
Owners of 1927-built houses report using this to locate framing after electronics failed them, and the rubber housing keeps it from scuffing fresh plaster. It is also a decent confirmation tool after an electronic scan, since a metal hit under your pencil line means you found the framing.
When the Stud Ball is the right tool
It is the right tool when your wall is plaster over wood lath and your real question is where the framing runs. Lath nails go into studs, so a magnet that grabs nails is reading the framing directly, with no interpretation involved.
It is also the fastest way to map a whole wall. Sweep horizontally at one height, note the hits, then sweep a foot higher and confirm the line repeats. That gives you a stud layout faster than calibrating anything.
Where it falls short
It locates fasteners, not stud width, and a fastener is not always at the centre of the stud. For a small picture hook that is irrelevant. For a 60 inch television bracket driven by two lag bolts, you need to know both edges.
It is also strong enough to snap onto a toolbox, a socket or a belt clip, which is where most owners lose it. Keep magnetic cards and media well away from it.
5. Kreg Magnetic Stud Finder with Laser-Mark for Guided Drilling
Kreg KMM1000LZ Magnetic Stud Finder with Laser-Mark for Wood & Metal Studs
Class 2 laser projection
Two rare earth magnets
Centred marking notches
Bubble level
Pocket sized
Pros
- Laser projects the stud location so both hands stay free for drilling
- Two rare earth magnets grip the wall on their own at a hit
- Built-in bubble level and centred notches aid accurate marking
- Compact and durable enough for daily job-site carry
Cons
- Magnetic only so it finds fasteners rather than full stud width
- Laser is a visual guide only and confirms nothing behind the wall
The Kreg is a magnetic finder built around one job: getting a mark onto the wall while your hands are busy. Two rare earth magnets stick it to the surface at a hit, and a class 2 laser projects the stud position so you can line up your drill without holding anything.
On plaster over lath, that self-holding behaviour is more useful than it first appears. A single-hand sweep on a fragile wall means you are less likely to push hard enough to scuff the surface.
When the Kreg earns its spot
It earns its spot when you are mounting something that needs one accurate hole rather than two. A laser line lets you centre a single anchor precisely, and the bubble level keeps it true on walls that are not perfectly plumb.
The centred marking notches and level make it a good second tool to keep in a bag with a multi-sensor scanner. Use the electronics for layout, then use the Kreg to place each hole.
Where it falls short
It is magnetic only, so it shares the Stud Ball’s limitation: fasteners, not stud width. If your fix needs two bolts spaced either side of a stud centre, this cannot tell you where the edges are.
The laser is a projection, not a measurement. It shows where the tool is, nothing about what is behind the plaster.
6. The Original StudBuddy as the Simplest Plaster Confirmation Tool
The Original StudBuddy® Magnetic Stud Finder – Made in the USA – Easy to Use Stud Finder – No Batteries Required – Powerful Magnet Stud Finder – Stud Finder for Drywall and Wood
Encapsulated neodymium magnets
No batteries
Hangs on the wall
1.6 ounces
Includes a case
Pros
- Foolproof magnetic detection with no batteries and no false beeping
- Finds framing in seconds and hangs there leaving both hands free
- Owners report success on plaster and lath as well as drywall
- Very low cost with a large long-standing review base
- Lightweight enough to keep in a drawer permanently
Cons
- Manufacturer states it is not intended for lath and plaster
- Modest magnet strength that can miss fasteners
- No built-in level on this original version
- Finds screws and nails only
- not full stud width
The original StudBuddy has the largest review base of anything we looked at, and the reason is simple. There is no calibration, no battery, no mode and no false beep. You sweep it, it sticks, and it hangs there while you work.
Owners repeatedly report better results on plaster than battery scanners gave them, which matches what you would expect from a tool that just grabs steel. Several use it as the confirmation step after an electronic scan.
The honest caveat is in the documentation. The manufacturer specifies drywall and wood use rather than lath and plaster, so treat it as a general magnetic finder rather than a plaster-specific one. We include it because the owner reports are consistent and because a cheap second opinion costs so little.
Against the Stud Ball, the difference is grip strength. The StudBuddy is lighter and finds drywall screws easily. Through several inches of plaster to a small lath nail, the 27 pound pull has more to give.
When the original StudBuddy is enough
It is enough for hanging a light frame, a curtain rod or a shelf on standard framing where any screw or nail will do. For most homeowners, that covers a large share of the jobs people buy a stud finder for.
It also works well as a second opinion after a deep-scan finder gives you an uncertain result. Two tools disagreeing on plaster is information you want before you drill.
Where it falls short
Magnet strength is modest, so on thick plaster it can slide over a nail without a solid grab. The 1927-built-house owners on r/HomeImprovement still finish the job with a #4 finish nail probe, which tells you how much people trust the read.
This original version has no built-in level. The newer StudBuddy V2 adds one, and if you want a level in the same tool, buy that version instead.
7. DEWALT DW0100 for Drywall and Plywood Rooms
DEWALT Stud Finder, 3/4”, Locate Framing Studs Efficiently with LED Arrows, Ideal for Wood and Metal, AAA Batteries Included (DW0100)
3/4 in detection depth
Center-find channel
Constant auto-calibration
LED arrows and audio
AAA included
Pros
- Auto-calibrates continuously so there is no setup step
- LED arrows plus an audible alert for visual and audio guidance
- Center marking channel helps mark a line across the stud
- Slim profile that is easy to hold and store
- AAA batteries are included in the box
Cons
- Manufacturer states it will not detect objects in plaster
- Will not locate non-ferrous or plastic objects such as pipes
- 3/4 in is the shallowest detection depth in this group
Auto-calibration is the feature that makes this one pleasant. It recalibrates as you move, so there is no blank wall to find and no start button ritual before every pass. The LED arrows show which way you are moving relative to an edge, and the audio alert confirms without looking down.
The problem for this article is stated plainly by the manufacturer. DEWALT says it will not detect objects in plaster, concrete, mortar, block, brick, carpeting, foil-faced material, metal surfaces or ceramic tile.
Add a detection depth of 3/4 inch, the shallowest here, and the reason for the 12 percent one-star share in owner reviews becomes obvious. On a standard drywall wall it is a good tool. On plaster it is the wrong tool.
We include it because many houses are a mix. If you have a basement or an interior partition that is plain drywall, this is a sensible, well-supported choice for that part of the project.
When the DW0100 works well
It works well on new drywall, plywood sheathing and standard plasterboard, where 3/4 inch is more than enough to find a stud. The center marking channel and the arrow guidance make layout quick.
It is also the easiest of the electronics to learn. Nothing to set, nothing to hold still for, and the batteries are in the box.
Where it falls short
On plaster it fails by design rather than by defect. With 3/4 inch of reach and an explicit manufacturer exclusion, it will not read a standard plaster and lath assembly.
It also cannot see non-ferrous metal or plastic pipes, which matters more as walls get busier with plumbing and electrical runs.
8. FNIRSI WD-01 for Metal, Wire and Copper Scans
FNIRSI WD-01 6 in 1 Rechargeable Stud Finder Wall Scanner, Positioning Hole
6 scan modes
LCD display and audio alarm
Rechargeable battery
Ferrous reach to 4.7 in
Positioning hole for marking
Pros
- Positioning hole marks stud edges and centre before drilling
- Rechargeable battery means no spare cells to carry
- Six modes reach 4.7 in for ferrous metal and 3.9 in for copper
- Clear LCD readout with an audio alarm
- Manufacturer states it works on lath and painted walls
Cons
- Edge and centre detection is unreliable on plaster and lath
- AC detection can be over-sensitive and flag wires that are not there
- Some reports of missing a metal plate behind drywall
- Needs periodic recharging
The WD-01 is the most capable electronics on paper in this group. Six modes cover exact scan, depth scan, non-ferrous metal, ferrous metal, AC wire and copper wire, and the numbers are generous, with ferrous detection quoted to 4.7 inches and copper to 3.9.
On a plaster wall, the LCD readout and the positioning hole are the parts that earn their keep. The hole lets you mark the edge and centre without the unit shifting under your hand.
Be careful with the centre feature here. One long-form owner review specifically on plaster and lath reports that edge and centre detection gives unreliable readings on those surfaces, while the nail and metal detection continues to work. That is exactly the split we have seen with electronics on old walls.
The AC mode also tends to over-report. A warning on every pass tells you little, so treat it as a prompt to probe carefully rather than a definite result.
When the FNIRSI WD-01 is the right buy
It is the right buy when your project is more than framing, such as running new wiring in a wall you suspect already has cables in it, or locating metal conduit and copper before you drill. Those modes go deeper than any other finder here.
For an old house where knob-and-tube may be present, a dedicated live-wire mode with a stated detection depth is worth having in the bag even if you also carry a magnet.
Where it falls short
The stud centre reading, which is the reason most people buy a stud finder, is the least reliable part of it on plaster. For that job a 13-sensor finder or a magnet beats it.
Several reviews also report a metal plate directly behind drywall going undetected, and the rechargeable cell needs regular attention.
How to Choose a Stud Finder for Plaster Walls
Start with the wall, not the tool. The tool choice that works on plaster over wood lath can be useless on plaster over metal lath, and nothing you buy fixes a wall with no framing in it at all.
Measure your plaster thickness first
This takes five minutes and it decides how much depth you need. Find an existing hole, a removed picture hook, an unfinished closet or an attic edge. If there is no hole, drill a small one in an inconspicuous spot and measure how deep it goes before you hit framing.
On a standard lath and plaster wall, plaster plus lath usually puts the stud face within reach of a 1.5 inch scanner. Where build-up from patching pushes past that, you need the deeper units or you need to probe. If a punch goes well past 2 inches without hitting wood, you are likely looking at masonry backing rather than studs, and no consumer tool will help.
Match the tool to the wall type
Magnetic. Best for plaster over wood lath, because lath nails are steel and are driven into studs. Fast, battery-free and the most recommended tool on forums. Its limit is that it gives you fasteners, not stud width.
Entry-level electronic. Best for drywall and plywood. Under 1 inch of reach makes these useless on standard plaster, and several manufacturers exclude plaster outright.
Deep-scan multi-sensor electronic. Best when you need a stud centre for mounting hardware. Sensor count drives how steadily it reads through lath, and anything under 9 sensors struggles with nail rows.
Imaging or radar-style scanners. Best when you need pipes and wiring mapped as well as framing, and in drywall rooms they are a genuine step up. Several are documented as not for lath and plaster, so check before buying.
Read the exclusions, not just the depth
A stated 1.5 inches of detection depth means nothing if the manufacturer excludes plaster from the supported surfaces. Three of the eight products here name plaster or lath in their documentation, and two exclude it outright. That single line decides the purchase more often than any specification.
Just as important, a stated depth is measured in ideal conditions on a flat surface. Thick plaster, uneven skim coats and a stud set back at an angle all reduce what you actually get.
Live wire and knob-and-tube safety
Old houses may have knob-and-tube or cloth-sheathed wiring that a modern live-wire detector does not always register. Treat any wire alert as a warning to probe carefully, never as a clearance.
Before you drill in a house of unknown age, confirm with a non-contact voltage tester at two points, keep your drill a slow speed so you can stop the moment you feel resistance, and know where your panel is. Do not rely on the stud finder as your only check.
Skip phone stud finder apps
Apps read the same sensors your phone already has, a magnetometer affected by steel reinforcement and a gyroscope, and they were never designed for a layered wall. Forum consensus is blunt about paying for access and getting nothing. The one phone-based device worth mentioning is a dedicated imaging unit that ships with its own unit and network, and even that excludes lath and plaster.
How to Scan a Plaster Wall Without Guessing
1. Anchor the layout on an outlet or switch
Electrical boxes are fastened to the nearest stud, so the box itself tells you where framing runs. Open owners of 100-year-old houses use outlets as their guide for exactly this reason. Find one stud near an outlet, then measure 16 inches on centre in both directions to find the rest.
2. Calibrate or start, depending on the tool
Multi-sensor finders that need no calibration can start anywhere, including on top of a stud. Single-sensor models need a blank stretch of wall, which on plaster means a spot with no lath nails and no patches. Hold a calibration there until the signal settles.
3. Scan slowly, in two directions
Speed is the most common reason for a bad read, and it shows up in forum threads repeatedly. Move the tool a couple of inches per second, not across the wall in a sweep. Then repeat the pass vertically. A real stud edge repeats on both passes, a nail or patch usually does not.
4. Mark with painter’s tape, not pencil
Pencil marks disappear into plaster texture and old paint. Small tape tabs cost nothing, hold a mark on a fragile surface and can be pulled off without touching the finish.
5. Confirm with a magnet
Run a magnet along the line you marked. If the magnet grabs metal exactly where the electronics showed an edge, you are over framing. If the electronics showed an edge and the magnet finds nothing, you may have hit a pipe, a wire or a patch compound repair.
6. Pilot hole before the big bit
Drill a 1/16 inch hole first. If you hit solid wood within about an inch and a half, you found the stud. If you break through into a void full of nails, you are in lath space, so move and probe again. Lath and plaster repair is straightforward, but a full-size lag bolt hole is not.
7. Know when there is nothing to find
Some older walls have no framing behind them, and remodels sometimes left plaster over a patchwork of brick and rubble. If a magnet and a deep-scan finder both come up empty across a whole wall, stop probing and look for an alternative fix such as a spreader anchor or a surface-mounted channel.
Frequently Asked Questions
What is the best tool for finding studs in plaster walls?
A deep-scan electronic stud finder with 9 or more sensors and at least 1.5 inches of detection depth, paired with a magnetic finder for confirmation. Electronics give you the stud centre for mounting hardware, while a magnet reads the steel lath nails that tie plaster lath to the framing.
Do stud finders work on plaster walls?
They work, but only with enough detection depth and the right tool class. Plaster stacks multiple layers that blur the signal, and rows of steel lath nails create false edges on electronic scanners. Magnetic finders read the nails directly and stay consistent on plaster over wood lath.
Will a magnetic stud finder work on plaster walls?
Yes, on plaster over wood lath, because lath nails are steel and are driven into the studs. The catch is that a magnet locates fasteners rather than stud width, so it tells you a stud is behind that point without telling you where the centre or the edges are.
Is a magnetic or electronic stud finder better?
Use both. Sweep a magnet across the wall to map the framing quickly, since it cannot be fooled by plaster density or lath. Then use a multi-sensor electronic finder to locate the centre and edges for mounting. Magnetic only for speed, electronic only for precision.
Are there still studs in plaster walls?
Usually yes in homes built before about 1940, at 16 inches on centre, but not always. Some plaster was applied directly over masonry, and some remodels left patched walls with no framing. A magnet sweep plus a deep scan tells you quickly, and both coming up empty means no stud there.
Why does my stud finder keep giving false readings on plaster?
Lath nails and wood lath strips are producing a row of false edges, and scanning too fast makes it worse. Calibrate on a blank area, move a couple of inches per second, and repeat each pass vertically. Marks that do not repeat on the second pass are not framing.
Final Verdict
If you own one tool for plaster walls, make it a multi-sensor deep-scan finder such as the Franklin ProSensor M210, then add a strong magnet like the Rack-A-Tiers Stud Ball for mapping. That pairing covers location and centring, and it is what we carried through every wall we scanned in 2026.
Measure your plaster thickness first, check whether your wall is wood lath or metal mesh, and treat any wire alert as a reason to probe carefully. If you want more guidance on mounting hardware once you have found the framing, our stud finder guide for hanging shelves covers anchor choices for lighter loads.