On Aug 27, 11:13*pm, Ivan Vegvary wrote:
I own two stud finders and neither is giving me consistent results. *Need to find all of the ceiling joists in my kitchen so I can install 2 light tubes and 18 can lights. *Symmetry is important. *Would like to put in 14" diameter daylight tubes so joist placement is important. *
My problem is that the ceiling consists of 1/2 inch drywall under 1/2 inch plywood. *This is throughout the house and is probably why the stud finders are not consistent. *Complicating this is the fact that the joist are all over the place and not necessarily parallel. *I have a few 13" gaps and a few 17" gaps etc. *I know this from measuring up in the attic. *Further difficulty is that I have about 24" of blown in insulation. *If I had drywall only (you lucky *******s) I would simply go in the attic and shove an awl down along side each joist, and then run chalk-lines down below.. *Can't shove the awl through the plywood! *So I'm working down below on a ladder with a yogurt can attached to my portable drill (wife doesn't like dust) and it takes me about 6-7 holes to locate a single edge of a joist. *Needs to be repeated at the other end which takes just as many tries. *The next joist can be measured out 16 inches and still takes about 5 holes due to irregular placement. *All together I have about 48 locations to do. *Way to slow.

All alternative ideas appreciated. *You're welcome to call me an idiot if it pleases you. *Just help me save some time and effort.

Ivan Vegvary

P.S. *I have about 48 findings not because the kitchen is huge, but because a steel beam runs down the middle of the room below the the ceiling and I cannot run a chalk line through it.

tear down the cieling for maximum symmetry placement.

otherwise you are just screwing around and theres a big likelyhood of
unknown obstructions

like water sewer fireblocks joists at wierd spots etc etc.

or go with surface mounted fluroscent fixtures that will be easier to
adjust location of.....