Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

i picked a tv mount from ikea. The tv itself is being mounted to some paneling which in turn is mounted to set of wooden draws. In addition, it gives you hardware to mount the panels to the walls. Its not really meant to support any weight, just to keep it from swaying back and forth. So i picked up a cheap stud sensor (zircon e30) but i'm not having very good luck with it. as soon as i start sliding it, it usually just starts indicating an error. Occasionally it tells me there's a stud, but on subsequent passes the results are far from exact. Right now i think i have an idea of where two studs are but it's a very rough guess.

I'm wondering if this is because this model is junk, or could i have lath and plaster walls? I'm pretty sure the walls are not sheet rock, just judging from the way they have crumbled when i tried to put a screw in them previously. Usually the paper coating on plaster doesn't allow it to crumble like that. Plus sheetrock usually seems to crumble more into a fine powder and this crumbles more into sand or little pebbles.

so does anyone know if there's a way i can tell if the walls are lath and plaster? or does anyone know if this stud finder is crap? they do make a slightly more expensive model which is supposed to work better with lath and plaster walls. i just dont want to go and spend the money buying if it i dont really need it. plus i'll probably wind up using it this one time and never see it again.

any suggestions? i did try knocking on the walls and trying to hear a difference, but that wasn't really working for me.

edit: just wanted to let people know i used this sensor: http://zircon.com/products/metal_m40.html and it seemed to work pretty well. So if you have lath and plaster walls, might want to give that one a try.

share|improve this question

4 Answers 4

up vote 8 down vote accepted

From your description of putting a screw into the walls, it certainly sounds as if you have lath-and-plaster. Another sign is the color of the dust: with drywall, it will be very white and uniform, whereas with lath-and-plaster, it's greyish and has darker flecks.

A lot of stud finders work by detecting the change in the dielectric constant of the wall as you move horizontally across the wall. Stud finders have a hard time with lath-and-plaster because the plaster is solid and can often be 1/2" thick, then underneath the plaster you there are only small gaps between the wood lath, so you never really get the sharp change in capacitance that they look for. On the other hand, drywall is spongy so there's less material between the stud finder and the stud that it's supposed to be sensing.

I had a deep-scan stud finder, and it wasn't that reliable, but I developed a technique that I had reasonable success with: do several scans at different heights and different starting points on the wall, noting where it said there was a stud. I also found that scanning slowly was better than faster. Eventually, I would get to an "average" location that was a pretty good guess.

I later learned (at least in my house) is that there's a stud on each interior wall right where it runs into an exterior wall. I could then mark 16", 32", etc. back from that stud and be OK.

share|improve this answer
    
I wasn't too keen on just measuring between since that assumes whoever put the wall up did so in an orderly way. After looking at the zircon site they have a different model of detector, which is supposed to work better with lath and plaster walls. i ordered it on amazon last night and should have it tomorrow. Hopefully that'll do it for me. Otherwise i suspect i'll be drilling exploratory holes near the baseboard to find out where the studs are. btw, i did try your method and it sorta works. I do have a rough idea where i think one stud is.but i'd rather be precise if i can. –  merk Nov 17 '10 at 18:00

Look for wall outlets. They are usually mounted on a stud. Then start measuring in 16 inch increments to find other studs. As a backup, I would use a small finish nail to hunt for the stud in the area that you want to put the TV in. Some studfinders have a "hi" and "low" setting that will adjust how sensitive it is to things behind it. Sometimes for instance, its harder on external walls because there is insulation in them. Maybe go to Home Depot or Lowes and buy another brand of stud finder. If it doesn't work you can always return it. Another kind of stud finder has a magnetic sensor and detects nails which are in the studs. You could try that type.

share|improve this answer
    
i'md 90% certain this is a lath an plaster wall. and from the zircon site it says this model might not work well on that wall and suggest the m40 model. I was just about to take a best guess estimate from using the e30 and drill a small hole to see if i hit a stud. thanks for the suggestion about the wall outlet, i'll try using that as a guide as well –  merk Nov 17 '10 at 4:12
2  
In my lath-and-plaster walls, I had outlets between the studs: there's a 1x6 nailed to the studs and the outlets or switches are mounted in cut out holes in the 1x6. –  Niall C. Nov 17 '10 at 5:35

I've come to rely on a pair of neodymium magnets for all things wall-related. A single magnet will help you find studs (namely, the nails and screws in the drywall or lath), and help you avoid nailing into other nails and nail plates (or piercing your wiring).

AND, while not relevant to your current problem, having TWO magnets will even let you go one step further and let you precisely line things up across a wall. I just dragged some 300 feet of cable up two stories to my attic by only cutting two holes in my wall (at the top of each floor to drill through the wall plates) by using a pair of neodymium magnets to line everything up. No exploratory holes needed.

share|improve this answer
    
heh - i sorta had that idea although i wasn't sure if they'd be able to pick up on the nails/screws in the studs or not. I actually tried installing a metal detector app on my android phone to do this. It sorta worked but it was very flakey. So i'm just going to wait until tomorrow and try that other zircon detector. Which i believe is also just basically a metal detector. –  merk Nov 17 '10 at 18:02
    
what size magnets would you need to be effective? –  hometoast Nov 30 '10 at 14:16
1  
I've used rather small ones (about 3/8" dia, 3/16" thick) with great success. –  Nate Nov 30 '10 at 14:34
    
Works great with regular drywall too! Just solved my problem :) –  Shrout1 Sep 1 '13 at 18:24
    
I took apart a few old hard drives, inside there are very strong magnets that work great for this purpose. –  mikey Nov 12 '13 at 12:54

I took off the baseboard. With a hammer I broke off some plaster and found the studs. I found the height I wanted and drilled my holes, mounted the bracket then put the baseboard back on. It took about 45 minutes total.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.