I am trying to find studs in the ceiling to drill holes for a heavy lamp. I need the stud to be at least two inches wide in order to get all the screws inside the stud.

While using the stud finder I am finding that the stud is probably just 1 inch wide. Does that make sense ?

I feel like i am doing something wrong since otherwise the manufacturers wont make products that require two inch wide studs.

  • What type of ceiling? Most will have 2 inch joists or rafters. Inch and a half if measured. Stud finder might be off or you have a type of hanging/drop ceiling. Any chance of pushing small nails where lamp is going to check actual size.
    – crip659
    Mar 31, 2021 at 17:27
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    In a ceiling, the "studs" are called "joists" or "rafters". Also, in the US at least, they're commonly made out of "2-by" material which is a nominal measurement (2 inches wide by 4 or more inches tall), but are actually 1.5" wide. I would imagine that your instructions call for mounting into a "2 by" rafter because that is the nominal specification, and that if you mount it into a 1.5 inch wide rafter, you'll be just fine. If you'll edit the exact make/model into your post and include a picture of the instruction in question, you'll get clarity.
    – FreeMan
    Mar 31, 2021 at 17:38
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    "otherwise the manufacturers wont make products that require two inch wide studs" False assumption. Heavy lamp? it does not get mounted to a box?
    – Alaska Man
    Mar 31, 2021 at 17:38
  • You're lucky if the joists/rafters are in the correct spot to hang your lamp - what do you do if you need to hang it between them? (you need some sort of block/noggin to take the load between the two joists)... Saw a few good ideas over here doityourself.com/forum/electrical-ac-dc/…
    – Mr R
    Mar 31, 2021 at 17:49
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    Let's see a photo of your lamp mount and of your ceiling. Unless your lamp weighs hundreds of pounds it is probably designed to be hung from a ceiling box or from a single decorative hook that is screwed to one joist. As others have noted, the joists are very unlikely to be 1 inch wide. Unless you have a suspended ceiling, then you might not have anything suitable to hang a heavy lamp from. Are there any rooms or hallways on the same floor with ceilings that are higher than in this room?
    – jay613
    Mar 31, 2021 at 18:57

2 Answers 2


You are correct that "two-by" lumber is standard fare for ceilings. What you're missing is that "two-by" lumber is actually 1-1/2" wide.

1-by is 3/4" wide.
2-by is 1-1/2" wide.
4-by is 3-1/2" wide.
Other sizes, subtract 3/4".

And manufacturers don't make products that require 2" wide studs. That would imply some sort of pre-war construction using rough-sawn timbers.

In the early days, a 2x4 was milled 2" x 4". Then it was run through a jointer to make one side flat, then (using the jointed side) a planer to make the other side parallel to the first side, then more passes through the planer to make both sides smooth. Same thing in both axes. Early experience was that rough-cut lumber was irregular enough that 1/2" of material would be used up in all this jointing and planing. So the target "finished" size was the finished timber was 1-1/2" x 3-1/2".

Contemporarily, mills have gotten better at their game, and are able to rough-saw the lumber more precisely, so they're not really wasting 1/2" anymore.


Most stud finders aren't that accurate within an 1/8 to 1/4" of the stud, so when you're measuring 1", the stud is probably 1-1/2", the narrow end of a 2x4.

I always get the exact location of a stud buy getting the approximate location with a stud finder and then punching a few holes in the ceiling with a small Phillips screwdriver to each side of the stud till the screwdriver "misses" each edge. Now you know exactly where it is and how wide.

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