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Does Stud Finder Work on Plaster Walls? (Answered)

Plaster walls are preferred nowadays due to their better fire-resistant capability, better insulation, and their unique aesthetic values. But one of the greatest setbacks of plaster walls is that they tend to be very thick and uneven.

Now, let us discuss whether stud finders work through plaster walls or not and learn some fun facts regarding it.

Stud finder work on plaster walls

The standard stud finders aren’t strong enough to detect the studs through plaster walls. While the magnetic stud detector isn’t strong enough to detect the metals in a stud through the plaster, the electric stud finder cannot give accurate readings since they depend on the density of the walls.

The hand-held magnetic stud detectors and electric stud finders, mainly fall into the category of standard stud detectors. They fail because:

Working procedure of a magnetic stud detector:

These devices detect the screws and nails driven in a stud, and in some cases, the studs–if they’re made of metals. 

The detector looks for materials that conduct electricity and show magnetic properties and discards any material that’s an insulator since they show little to no magnetic properties. 

The detector beeps when they find any metal since metals have electric properties, and ultimately magnetic ones.

Working procedure of an electric stud finder:

These stud finders use the dielectric reading of a wall and let the user know the presence of a stud once there’s a change in the dielectric readings. 

Moreover, this is more reliable since studs might not always be metallic and finding out the presence of those frames with the help of density readings seem safer and accurate.

Characteristics of a Plaster Wall:

A plaster wall is usually composed of lime, gypsum, or cement with sand and water. 

It’s thicker–almost 7/8 inches without the lath and if lath is added, the wall becomes 1-inch thick, which is thicker than most drywall, more fire-resistant than drywall, and not to mention more uneven. 

This uneven, or rough texture is what makes it desirable and gives an aesthetic theme to homes that represent an old or ancient theme.

They fail because:

While the magnet in a magnetic detector isn’t always strong enough to detect metal through the wall because plaster walls are thicker than drywalls. 

The dielectric readings given by an electric finder aren’t accurate due to the unevenness of the plaster wall.

Do you need a special stud finder for plaster and lath walls?

Yes, a special or strong stud finder is needed to detect or find the studs behind lath and plaster walls. Lath and plaster walls make very thick walls together (almost 1-inches thick), thicker than drywall. 

Drywalls are mostly ½ inch thick, making lath and plaster walls thicker than drywall.  Additionally, the texture of the wall is uneven and rough due to the components used in it. 

Besides, the reason plaster walls are desired in some of the houses instead of drywalls is the roughness of their texture. 

Therefore, the above-mentioned characteristics make the work of a standard stud detector hard and non-accurate. Hence, special stud finders are used in this case. 

Some are Franklin Sensors ProSensor Professional Stud Finder, StudPoP “Grip” Magnetic Stud Finder, Zircon Handheld Electronic Metal Detector, and so on.

What stud finder works on plaster walls?

Some stud finders that will do the work:

Strong Magnetic Stud Finders: 

One of the examples is StudBuddy Plus magnetic stud finder. Because, these finders have a strong enough magnet that detects the metals, be it the screws driven in a stud or a metallic stud itself, and attaches itself to the wall at that place.

Strong Electronic Stud Finders: 

Even though electric finders have chances of giving wrong density readings due to the unevenness of plaster walls, a strong detector can detect the metallic and non-metallic studs through tile, drywall, plaster walls, and so on. 

Zircon Handheld Electronic Metal Detector is one of the finest examples.

Stud Finders using Radar Technology:

These stud finders are one of the strongest and can find almost anything behind a drywall or plaster walls–studs, pipes, lines, etcetera. BOSCH D-Tect 150 Wall and Floor Scanner is an example of finders using radar-tech. 

How far apart are the studs in plaster and lath walls?

The standard distance between two studs in plaster and lath walls is 16-inches to 24-inches, depending on the age of the house

In the more modern houses, the distance tends to be 16-inches from the center of the stud but it won’t be lengthier than 24-inches even in the old ones.

A sure way to find studs–apart from eye-balling, driving a nail continuously in different places, or pressing the wall until a stable point is found– is to look out for outlets. 

Well, this is because, they are always, almost 99% of the time, present on either side of a stud. And then, if a measuring tape is held and calculated, a stud will be present every 16 or so inches, never exceeding 24-inches. 

How to find stud in thick plaster wall?

There are two ways by which a stud can be found inside plaster walls, and they will be explained below:

Using a very strong magnet:

Buying a magnet:

There are many magnets out there in the market but we’re looking for the strongest ones. Neodymium magnets or rare earth magnets are some permanent magnets that are very strong.

Finding the nail or stud:

The magnet is then placed on the wall to find out the nail or screw driven in the particular stud. 

If a nail isn’t already on the wall, one can start from the area near the electric outlets, since they’re most of the time installed on either side of a stud.

If the stud is metallic, the magnet will stick on the plaster right on top of that stud or it might stick on top of a nail driven on the stud. Our work is to move the stud across the wall until it sticks to a specific area and then mark the area.


This method is comparatively cheaper and hassle-free. 


The method is unreliable since the magnet might detect anything that’s magnetic behind the wall. It is tedious and a lot of work.

Using a strong stud finder:

Finding the right stud finder:

Not every stud finder in the market will work for plaster walls. This is because these walls tend to be very thick and most stud finders are designed to only scan a few parts of an inch. 

The stud finders that come with the ‘deep scan’ option are the best for this. They’re cheap, accurate almost all the time, and user-friendly.

Placing the stud finder:

After placing the stud finder in the general area of a stud being present, we move it across the wall till we hear a beep and laser pointing out the place of a stud

Rightly placing a stud:

It is to be kept in mind that these stud finders will detect only one edge of a stud. Additionally, after marking that place, we will have to swipe the finder from the other side to find the other edge of the stud. 

The middle point of that stud will help us find the next stud with the help of a measuring tape.


This process is more accurate than the previous one and more time-saving.


The price of these scanners tend to be more than strong magnets.

Final thoughts

The standard stud finders don’t usually work on plaster walls since they tend to be very thick–almost an inch– and uneven due to the components present. For that, we either need very strong magnets or very strong stud finders–one which comes with the ‘deep scan’ option or the radar-tech scanners.