Our Tests Reveal The Stud Finders That Work For Lath And Plaster Walls

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Pro Tool Reviews tested six stud finders on a mock wall that included lath and plaster. The Franklin ProSensor M210/X2100 detected the center of every test stud but also produced false detections; the less expensive M70/X700 missed none and produced no false detections, though it was less precise and lacks AC detection.

Pro Tool Reviews tested six stud finders on a mock lath-and-plaster wall and found that two Franklin models performed best, though with different trade-offs. The M210/X2100 recorded on-center detection for every test stud, while the M70/X700 had no missed or false stud detections but was less consistently centered and does not detect AC.

In the report, Pro Tool Reviews says Tom Gaige built a test wall with separate sections of single-layer drywall, double-layer drywall, and lath and plaster, leaving a gap behind each section so testers could see what was being detected. The objects behind the wall included standard and metal studs, a stud with live AC, electrical conduit with live AC, PVC pipe, and a water-filled copper pipe. The supplied results focus on performance in the plaster section.

The Franklin ProSensor M210/X2100 scored 100% on-center detection, with no off-center readings or missed studs. Its results also showed 33% false stud detection and 100% AC detection. The report recommends taking repeated readings because a false signal may come from a pipe or another object. The listed price was $59.99.

The Franklin ProSensor M70/X700 recorded 67% on-center detection and 33% off-center detection, with no missed studs and no false stud detections. Its listed price was $21.99, nearly $40 below the M210, but the report says it does not offer AC detection. The other supplied results show the Zircon HD70 at 67% on-center detection, 7% missed studs, 47% false detections and 50% AC detection; the JAXWQ 139-FYELLOW recorded 60%, 7%, 33% and 50%, respectively.

Choosing a Finder for Plaster

The results matter to homeowners and tradespeople because lath-and-plaster construction can make stud detection less reliable than readings on common drywall. A mistaken mark can lead someone to drill in the wrong place, while a false detection may prompt an unnecessary hole or misdirect a mounting project. The report’s comparison gives readers evidence to weigh precision against price and extra features rather than treating all stud finders as interchangeable.

The two leading Franklin models serve different needs in the tests. The M210/X2100 delivered the strongest on-center result and detected live AC in the test, but its false detections mean users should verify marks. The M70/X700 was less precise about the center but recorded no missed or false stud detections, at a lower listed price. Its lack of AC detection is a limitation, particularly for work that involves opening a wall.

These are results from one test setup, not a guarantee that either model will behave the same way in every building. Wall thickness, materials, repairs and framing can vary. The report’s practical point is to compare multiple readings and avoid relying on a single signal before drilling or cutting.

How the Test Wall Was Built

The report notes that stud finders can misread even standard drywall: devices may mark a stud edge as its center, miss a stud, or signal where no stud is present. It describes a typical framing target as a stud’s 1½-inch-wide edge facing the wall, while cautioning that older homes may vary. That makes a repeatable method important, especially when the wall surface is thicker or less uniform.

For its approach, Pro Tool Reviews says testers moved each finder from a section without a stud until it indicated a center, marked the location, then repeated the process from the opposite side after resetting or recalibrating the device. The report advises averaging readings and repeating them when they do not agree. It also cautions that lath-and-plaster stud spacing may be inconsistent, so measuring a standard distance from one detected stud may not locate the next one reliably.

The publication converted test outcomes into percentages for five categories: on-center detection, off-center detection, missed studs, false stud detection and AC detection. The supplied source gives detailed plaster results for the Franklin M210/X2100, Franklin M70/X700, Zircon HD70 and JAXWQ 139-FYELLOW, while its introduction says six models were tested. The provided material does not identify the remaining two models or include their plaster scores.

“only one nailed the center of every stud”

— Pro Tool Reviews

Limits of the Published Results

The supplied report excerpt does not provide the names or plaster scores for all six tested models, nor does it state when the testing took place. It also does not give the number of individual readings behind each percentage, so readers cannot assess the sample size from the supplied material. The results are tied to the report’s mock wall and test objects; performance on a particular home’s walls may differ.

The source lists prices of $59.99 for the M210/X2100, $21.99 for the M70/X700, $29.99 for the Zircon HD70 and an unspecified price for the JAXWQ. It does not establish whether those prices remain current. The excerpt also ends before giving the report’s full comparison or final recommendation among the other models. While the tests included several objects that could be mistaken for studs, the supplied results do not give a complete breakdown for every object and every model.

AC detection should not be treated as a guarantee that a wall is safe to cut into. The report provides device test rates, not a safety certification or instructions for confirming that an area is free of wiring or plumbing.

Verify Marks Before Drilling

For readers applying the findings, the report recommends scanning from both directions and comparing marks rather than relying on a single pass. If readings disagree, repeat the scan and allow the device to reset as needed. Treat an isolated signal cautiously, since the test recorded false stud detections with several models and objects behind the wall can affect readings.

The supplied material does not announce a follow-up test or a new product release. The next useful information for comparing the full field would be the complete results for all six models, including the omitted two and the number of readings used to calculate each percentage. Until then, the published figures support a limited conclusion: in this test, Franklin’s M210/X2100 led on center accuracy, while the M70/X700 offered a lower-cost result with no recorded misses or false stud detections.

Key Questions

Which stud finder performed best on the tested plaster wall?

The Franklin ProSensor M210/X2100 had 100% on-center detection in the report’s plaster test. It also had a 33% false stud detection rate, so the report advises taking multiple readings.

Which tested model had no missed or false stud detections?

The Franklin ProSensor M70/X700 recorded no missed studs and no false stud detections in the reported test. Its on-center detection was 67%, and it does not have AC detection.

Can these results guarantee a stud finder will work in my home?

No. The percentages describe performance on one mock test wall. Materials, wall thickness, repairs and framing can differ from one building to another, so the report recommends checking marks with repeated scans.

Should I cut into a wall based only on a stud finder’s AC reading?

No. The reported AC detection rates are test results, not a guarantee that a wall is safe to cut. The supplied report does not provide a complete method for confirming that wiring, plumbing or other hazards are absent.

Source: rss