Problem for me is that the wall I have has NO outlets. There was a thread from 2004 about this and the answer was to find an electrical outlet to see which side had the stud and the measure 3/4' to find mid stud and then to measure either 16 inches or 24 inches from there for the other studs. This simple stud finder is a powerful magnet that pops into place when a stud fastener is detected. Finding studs in metal lath plaster walls. You could also try a cool product called StudPop which takes the magnet trick to the next level.

Keep in mind there are some spaces between lath vertically so if you’re not having much luck try moving the magnet up or down a bit so that it is over top one of the hidden nails. The reason this works is because the wood lath is nailed to the studs, and the magnet is attracted to those nails. Remove the cover plate and determine where the stud is. Go to the outlet box on the wall where you're going to mount the TV. They should detect the stud behind the lath and plaster. Some stud finders are designed to work on a 'deeper' wall. It has to be a strong magnet for this to work, so those floppy pizza magnets won’t cut it. Studs are usually on 16' centers, even when they were building lath and plaster walls. Every so often, the magnet will stick to the wall a bit on the stud location. Dangle the magnet against the wall and slowly move it horizontally across the wall. With greater pressure you may find a similar movement, indicating that the plaster is well keyed to the lath, but the lath is loose from the studs. To successfully fix to a lath and plaster wall you will need the following tools and products: Timber batten of chosen width and length (3 x 2 or 4 x 2 and around 1.8 2.4m long) Handsaw or chop saw. It works every time! Grab the strongest magnet you have and tie a piece of dental floss or string around it. This is my favorite method and the reason is simple.

Finding studs in lath and plaster walls