I have an antique sheetmetal ceiling of historical importance in my centenarian vintage home. As I am currently in the last stages of installing an AC system and the parts of the house that have vintage ceiling get exposed spiral pipe as to avoid ugly soffits or other forms of ceiling destruction (looks very, very cool), I actually need to suspend the pipe in one or two places. The ceiling is on the first floor and there is a carpeted bedroom above. From demolishing a patch of such a ceiling in another part of the house, I know (with a high degree of certainty) that between the joists and the sheetmetal is lath and plaster. I suppose I could anchor it into 3/8" lath but I would prefer a joist for extra firmness.
The problem, as you can imagine, is locating ceiling joists through a sheetmetal ceiling. I tried a really nice stud finder (Bosch) but that did not help much as the sheetmetal is blocking the signal. I also tried using it through the carpet upstairs but the experience was similar. Any idea how I can find a joist with a relative degree of certainty, as any mistake will leave a visible hole in the ceiling?
Best Answer
You might be able to pull the carpet a bit in a corner of the room. Perhaps you can find nails holding down the subfloor to the joists. A good place to start would be a closet where it would be easy to hide and tack back down. From this point it might be easier to guess what the typical joist spacing would be.
Typically ceiling joists will be spaced 12", 16", 19.2" or 24" OC. Rather than damage the ceiling it would be easier to pull up some carpet upstairs and try driving a nail or screw at each of these lengths and see which length grabs a joist.