Posts Tagged ‘nails’

We often get asked, why does my stud finder have trouble with lath and plaster when it works perfectly through drywall? Or, what is the best tool or technique for finding studs in lath and plaster walls?

The front of this lath and plaster wall is smooth - no problem for your stud finder.

The front of this lath and plaster wall is smooth – no problem for your stud finder.

Your Zircon stud finder finds studs by looking for an increase in density compared to where it was first calibrated on the wall.  Drywall and other manufactured sheet materials have very consistent density, but lath and plaster walls have very inconsistent density on the backside of the wall. This is where the plaster is squeezed between the lath and ‘keys’ onto the back of the lath and holds the plaster in place.

So, even if the front of the wall has a very smooth texture, the back of the wall is what gives your stud finder trouble because there are changes in density everywhere as you scan.

Shown here is a peek behind the wall. Lath and plaster walls have an irregular surface that are a problem for stud finders.

Shown here is a peek behind the wall. Lath and plaster walls have an irregular surface that are a problem for stud finders.

As a result, your stud finder can show a false positive (a stud indication when it is actually not a stud) when it finds an increase in density, even if it is just a glob of plaster.

The best solution is to use a Zircon MultiScanner® wall scanner that has Metal Scan Mode or one of Zircon’s dedicated metal detectors, such as the MetalliScanner® m40 or MetalliScanner® MT 6, so you can find the little nails or tacks that are fastening every piece of wood lath to the studs.

Use a Zircon metal detector to locate the nails that fasten each piece of lath to the studs.

Use a Zircon metal detector to locate the nails that fasten each piece of lath to the studs.

Since you can detect the nail heads all the way up and down the entire height of the stud with the Metal Scan mode, this is a much more reliable way to find studs.

Please see the video demo of an m40 finding studs through lath and plaster on the Zircon web site.

Note:  All photos were taken in a test lab environment.

Working on hanging a flat screen television or want DIY help? Make sure to take a look at our Zircon in the Real World blog, “Think Outside Your Wall“. For more useful tips, please follow us @zircontools or like us on Facebook.

 

 

 

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