How to Find Studs Behind Plaster & Lath Walls | Guide for Older Atlanta Homes

You’ve got a beautiful old home—maybe a 1920s bungalow in Virginia-Highland, a 1940s ranch in Decatur, or a charming Craftsman in Grant Park. The character, the craftsmanship, the solid construction—there’s nothing quite like an older Atlanta home.

And then you try to mount a TV.

You wave your stud finder across the wall. It beeps everywhere. Or nowhere. Or in patterns that make no sense. Welcome to the plaster and lath nightmare that every old-house owner eventually encounters.

Here’s the reality: Standard electronic stud finders don’t work reliably on plaster walls. But with the right techniques, you can find those studs and mount your TV securely.

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Why Plaster Walls Confuse Stud Finders

Understanding Plaster and Lath Construction

Before modern drywall (introduced 1940s-1950s, widespread by 1960s), walls were built differently:

Lath: Thin wood strips (about ¼” × 1½”) nailed horizontally across studs, with small gaps between strips

Plaster: Multiple layers of wet plite applied over the lath:

• Scratch coat (first layer, keys into lath gaps)
• Brown coat (leveling layer)
• Finish coat (smooth final surface)

Total wall thickness: ¾” to 1” of plaster plus ¼” lath = about 1” total (vs. ½” drywall)

Why Electronic Stud Finders Fail

Electronic stud finders detect changes in wall density—the difference between hollow cavity and solid wood stud.

On drywall:

• Clear density difference: hollow → solid → hollow
• Stud finder reads the change accurately

On plaster and lath:

• Wood lath runs everywhere, not just at studs
• Plaster density varies (thicker in some spots, keys through gaps)
• Metal mesh, nails, and reinforcement create false readings
• Inconsistent wall thickness further confuses sensors

Result: Your stud finder beeps constantly, randomly, or not at all.

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Proven Methods for Finding Studs in Plaster Walls

Method 1: The Magnet Technique (Most Reliable)

Why it works: Studs have nails or screws in them. A strong magnet finds metal regardless of wall density.

What you need:

• Strong rare-earth (neodymium) magnet
• Or magnetic stud finder designed for plaster
• Painter’s tape for marking

Technique:

1. Start near an edge of the wall (corner, window, door frame)
2. Move magnet slowly across wall surface in S-pattern
3. Feel for magnetic pull—indicates nail beneath
4. Mark each nail location with tape
5. Continue across wall, noting where nails align vertically
6. Vertical alignment of nails = stud location

Tips:

• Lath nails are in horizontal rows across studs
• Finding 3+ vertically aligned nails confirms stud position
• Use small magnet—easier to pinpoint exact location

Limitations:

• Time-consuming for large areas
• Plaster nails used in some homes create confusion
• Works best with patience and systematic approach

Method 2: The Nail/Test Hole Technique

Why it works: Physical confirmation beats electronic guessing.

What you need:

• Thin finish nail (or small drill bit)
• Hammer
• Flashlight
• Spackle for patching

Technique:

1. Choose an inconspicuous test location
2. Drive thin nail through plaster at 45° angle (toward expected stud location)
3. If nail hits wood within 1½”: you found the stud
4. If nail slides through into cavity: move over and try again
5. Studs are typically 16” apart—use this to extrapolate

Refinement:

• After finding one stud, measure 16” in both directions
• Test at predicted locations to confirm spacing
• Some older homes use irregular spacing—don’t assume

Patching holes:

• Spackle, let dry, light sand
• Holes are small and easily repaired
• Much better than drilling in wrong location

Method 3: The Wire Hanger/Probe Technique

Why it works: Physically probes the wall cavity to find stud edges.

What you need:

• Straightened wire coat hanger
• Drill with small bit (⅛”)
• Flashlight

Technique:

1. Drill small hole through plaster where you suspect cavity
2. Insert bent wire hanger into hole
3. Rotate wire to feel for stud edges on either side
4. Mark edges; stud center is between them

Advantages:

• Confirms exact stud edges
• Works regardless of wall composition
• Small test hole easily patched

Method 4: The Electrical Box Reference

Why it works: Electrical boxes are typically mounted to studs.

Technique:

1. Locate nearby outlets or switches
2. Turn off power at breaker
3. Remove cover plate
4. Look which side has the stud (box is screwed to it)
5. Measure from this known stud to find others (16” increments)

Limitations:

• Not all boxes attach to studs (some use bracket mounts)
• Only provides one reference point
• Requires working near electrical

Method 5: Sound/Knock Test

Why it works: Solid (stud) and hollow (cavity) areas sound different.

Technique:

1. Knock firmly with knuckle across wall
2. Listen for change from hollow sound to solid sound
3. Mark where sound becomes more solid
4. Verify with magnet or nail test

Limitations:

• Less reliable on thick plaster
• Requires good hearing and experience
• Best as initial scan, then verify

Method 6: Baseboard/Trim Reference

Why it works: Baseboards and crown molding are often nailed into studs.

Technique:

1. Look for nail heads along baseboard (fill may have shrunk)
2. Note pattern—nails likely hit studs
3. Extend vertical line from baseboard nail to TV height
4. Verify with magnet or test at that height

Limitations:

• Trim nails don’t always hit studs
• Baseboard may have been replaced
• Only useful if nail locations are visible

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Stud Spacing in Older Homes

Standard vs. Reality

Modern construction: 16” on-center (consistently)

Older construction: “Approximately 16 inches” with variations:

• 16” in some areas
• 24” in others
• 14” or 18” where carpenter felt like it
• Irregular spacing around doors, windows, corners

Why variations exist:

• No building codes enforced spacing
• Hand-framing by individual carpenters
• Working around existing features
• Regional construction traditions

What This Means for TV Mounting

• Don’t assume you’ll find a stud 16” from the first one
• Verify each stud independently
• Consider using all available studs even if spacing is irregular
• Blocking may be needed if studs don’t align with bracket holes

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TV Mounting Challenges Specific to Plaster

Challenge 1: Crumbling Plaster

Problem: Old plaster may crack or crumble during drilling.

Solutions:

• Use sharp masonry bit at slow speed
• Apply painter’s tape over drill location
• Don’t force—let bit do the work
• Consider washer plates to spread load

Challenge 2: Extra Wall Thickness

Problem: Standard mounting screws may be too short.

Solutions:

• Use 3” or longer screws (not 2.5” standard)
• Calculate: plaster (¾”) + lath (¼”) + into stud (1½” minimum)
• Total engagement: 2.5” minimum, 3”+ preferred

Challenge 3: Lath Obstruction

Problem: Lath prevents screw from reaching stud.

Solutions:

• Drill through lath (it’s just thin wood)
• Use masonry bit for plaster, switch to wood bit for lath
• Pre-drill pilot holes for easier screw driving

Challenge 4: Plaster Cracking

Problem: Plaster cracks radiating from drill holes.

Solutions:

• Tape before drilling
• Drill slowly, without hammer function
• Use sharp bits
• Consider larger pilot hole to reduce stress

Challenge 5: Hidden Mesh or Reinforcement

Problem: Some plaster contains metal mesh reinforcement.

Signs:

• Unusual resistance while drilling
• Metal shavings in dust
• Stud finder showing continuous metal

Solutions:

• Switch to metal-cutting bit
• Be prepared for slow drilling
• Double-check you’re not hitting something else (pipe, wire)

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Professional Tools for Plaster Wall Stud Finding

High-Quality Magnetic Stud Finders

Recommended products:

• StudBuddy (magnetic, designed for plaster)
• CH Hanson 03040 (powerful rare-earth magnet)
• Neodymium magnets (craft/hobby size, very strong)

Advantages:

• No batteries
• Works regardless of plaster composition
• Finds actual fasteners, not density changes

Deep-Scanning Electronic Finders

Products designed for plaster:

• Franklin ProSensor 710+ (deep scan mode)
• Zircon MetalliScanner
• Bosch GMS 120

Limitations:

• More accurate than standard finders but not foolproof
• Best used to narrow search, then verify with other methods
• Expensive compared to basic stud finders

Endoscope/Borescope

For looking inside wall:

• Insert through small hole
• See stud edges directly
• Also spots pipes, wires, obstructions

Useful when:

• Multiple test holes aren’t feasible
• You need to see what’s in the cavity
• Planning major installation

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Step-by-Step: Finding Studs for TV Mounting in Plaster

Complete Process

Step 1: Initial reconnaissance (5 minutes)

• Note location of electrical outlets (potential stud reference)
• Look for baseboard nail patterns
• Identify general wall construction

Step 2: Magnet scanning (10-15 minutes)

• Scan wall area where TV will mount
• Mark every nail/screw found with painter’s tape
• Look for vertical alignment patterns

Step 3: Verify with test holes (5 minutes)

• At suspected stud locations, drive thin finish nail
• Confirm presence of wood behind plaster/lath
• Mark confirmed stud locations

Step 4: Establish pattern (5 minutes)

• Measure between confirmed studs
• Check if 16” or other spacing
• Predict additional stud locations

Step 5: Verify mounting points (5 minutes)

• Test at exact bracket hole positions
• Confirm all mounting points hit solid wood
• Adjust bracket position if needed

Total time: 30-40 minutes (vs. 5 minutes on modern drywall)

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When to Call a Professional

Plaster situations that benefit from professional help:

Extremely old or fragile plaster:

• 100+ year old homes
• Visible cracks or damage
• Plaster that crumbles to touch

Uncertain wall construction:

• Can’t locate studs after multiple attempts
• Inconsistent stud spacing
• Unknown materials in wall

Valuable plaster:

• Decorative plaster moldings nearby
• Historic home with preservation concerns
• Expensive to repair if damaged

Heavy TV installation:

• 65”+ TVs requiring maximum security
• Full-motion mounts with leverage forces
• Situations where failure isn’t acceptable

What professionals bring:

• Experience with plaster wall peculiarities
• Multiple detection methods combined
• Proper tools for drilling plaster
• Insurance if something goes wrong
• Solutions for unusual situations

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Frequently Asked Questions

Can I use a stud finder at all on plaster walls?

Basic electronic stud finders are unreliable. Deep-scanning or radar-based models work better but aren’t foolproof. Magnetic stud finders work excellently on plaster—they find nails, not density changes.

Are studs always 16” apart in old houses?

No. Older homes often have irregular stud spacing. Verify each stud individually rather than assuming consistent spacing.

Why does my stud finder beep constantly on plaster walls?

The wood lath running across the entire wall makes the stud finder detect “solid” almost everywhere. The metal nails in the lath can also trigger continuous readings.

Can I hang a heavy TV on a plaster wall?

Yes, if you properly locate studs and use appropriate hardware. The plaster itself can’t support weight—you must reach the wood framing behind it.

My nail test hit something hard but not wood—what is it?

Possibilities include: fire stopping (horizontal blocking), plumbing, metal mesh reinforcement, or the lath itself. Probe further or use alternative method to identify.

Should I use longer screws for plaster walls?

Yes. Account for plaster thickness (¾”) plus lath (¼”) plus minimum 1.5” into stud. Use 3”+ screws versus the 2.5” screws common for drywall.

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Atlanta’s Plaster Wall Neighborhoods

Older Atlanta neighborhoods with prevalent plaster construction:

Intown:

• Virginia-Highland (1920s-1940s bungalows)
• Inman Park (Victorian and Craftsman)
• Grant Park (historic homes)
• Candler Park (early 20th century)
• Kirkwood (mix of eras)

Decatur:

• Historic Decatur (pre-war homes)
• Oakhurst (1920s bungalows)
• MAK District

Other areas:

• Brookhaven (older sections)
• Druid Hills (historic estates)
• East Lake (vintage bungalows)
• College Park (historic district)

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Professional Plaster Wall TV Mounting

Express Mounting specializes in older Atlanta homes with plaster walls:

✅ Multiple stud-finding techniques for accurate location

✅ Proper drilling methods that don’t damage plaster

✅ Appropriate hardware for plaster wall thickness

✅ Experience with Atlanta’s vintage home construction

✅ Insurance protecting your historic walls

Plaster Wall TV Mounting

Starting at $199

• Comprehensive stud location
• Careful plaster drilling
• Secure mounting with proper screws
• Cable management appropriate for plaster walls
• Patching of any test holes

👉 Visit ExpressMounting.com to schedule professional TV mounting in your vintage Atlanta home.

📍 Express Mounting — Trusted TV installation for Atlanta’s historic and vintage homes.