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Locating joists to add addtional sheetrock over existing ceiling.

Locating joists to add addtional sheetrock over existing ceiling.

Old 04-02-19, 05:18 PM
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Locating joists to add addtional sheetrock over existing ceiling.


I'm looking for advice on how to find my joists to mount some extra drywall on my existing finished ceiling. I'm adding mass to a basement room to begin a sound-proof for a sound studio.

When I put insulation into the ceilings and walls, I noticed the previous owner must have used little (1/2 inch) cross beams on the joists to mount the existing ceiling. Since the joists are 1/2 inch away from the existing drywall now, I have not been able to get a stud finder (deep scan models included) to find the joists so I can mark off where I need to screw in the new drywall.

Any ideas? I thought maybe to sand down the existing ceiling so I could mark the screws, or drill small pilot holes to chase down the joists, but both seem very time consuming and ineffective.

Pictures attached for reference.

Thank you!
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Old 04-02-19, 05:37 PM
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Welcome to the forums.

Do you know which direction the joists run ?
Find the first one and then measure over 16". Check for joist. Every 16" should be a joist.
Old 04-02-19, 05:41 PM
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They are really 1/2" thick? The "cross pieces" are called strapping. Typically you see 1x4s used as strapping, and they are 3/4" thick. Strapping is used to make it easier to hang sheets on the wider surface. Especially popular in Canada and northern US for some reason. Drywall is fastened to the strapping, not to the joists. So depending on how beefy the strapping is, fasten to it.

Quickest way to find your joists is with a nail along opposite walls. Once you find the centers, chalk lines. Check the lines here and there to make sure they aren't half lapped or something odd. Once you find a couple you should be able to measure aND mark each one... 16" on center in all likelihood.
Old 04-06-19, 11:34 AM
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Thank you both for your replies! (and for the vocabulary)

I will try that method.

Old 04-06-19, 03:46 PM
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You know where one joist is and which way they run. So go to each wall and drive nails until you hit the joist. Move away from the wall enough that you don't hit that strap. When you hit the joist drive nails close to the one that hits so you can find the center. Do this on each end of the first joist. Once you know the center of that one move over 16" and try again. You should be able to hit the center of the next joist. Oh, and leave a nail in the first one so you can hook the tape over it and measure 16". 32", etc. It is more precise that way. Leave the nails in the centers of the studs so you can hook a chalk line to them and snap lines.
BUT I think you might be asking for a problem screwing sheetrock to the joist if there is strapping between the joist. The ne drywall will draw up and put a bow in the lid between each strap. Seems to me your idea would be good for sound proofing but it is not a good idea to put up drywall and not have it tight to what ever you screw it to. So find the strapping the same way as you look for the joist. Put an extra screw wherever the strap crosses the stud. Best you can try to orient the new drywall so the joints don't land in the same place in the new as in the existing.

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