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dvdmovieman

Is lowering a ceiling this way safe?

dvdmovieman
18 years ago

I'm building a Home Theater in the basement and want to double-layer the drywall in the ceiling. Unfortunately, there are several electrical conduits running throughout my room-to-be. All I need is an inch or so to clear the conduit. Is is safe to nail/screw 2x4s to the existing joists, then attach 2 layers of drywall to these 2x4s? I'm worried about the weight.

Thanks for any advice you can provide!

Comments (9)

  • brickeyee
    18 years ago

    As long as you use enough fasteners for the 2x4s. Probably about every 10 inches with 16d nails.

  • logic
    18 years ago

    "All I need is an inch or so to clear the conduit. Is is safe to nail/screw 2x4s to the existing joists, then attach 2 layers of drywall to these 2x4s? I'm worried about the weight."

    Better safe than sorry; either consult your town construciton code official....or, a licensed structural engineer for a definitive and meaningful answer.

  • brickeyee
    18 years ago

    Two layers of drywall is well within the design limit for any structure built in about the past 40 years, and probably for even longer than that.
    Drywall in a per square foot basis is pretty light material. A 64 pound sheet would only be 2 pounds per square foot (4x8 sheets).
    The building code allowance for floor and ceiling is 10 pounds per square foot dead load.

  • logic
    18 years ago

    brickeyee, you may very well be correct.
    However, IMO, if people have questions about load or anything regarding structural support, it is not wise for them to take the advice of someone on an internet forum...since that person could just as easily be mistaken....or, they could easily misinterpret the reply. And, since the OP had to ask, that appears to mean that he does not have the knowledge to make that determination.
    For his own protection and safety (and that of his family and guests), he needs to get the OK from a known licensed professional. After all, if something should fail, even if it comes form a misinterpretation of what you have written, in the event of a problem or heaven forbid a tragedy, I'm sure a defense of liability using the claim "someone on an internet forum said I could do it" will hardly fly.
    Last but not least, codes vary from place to place...and there are some stupid ones out there; even though his plan may be OK as per BOCA, that does not mean it is OK with his town.

  • brickeyee
    18 years ago

    Give me a break.

  • logic
    18 years ago

    "Give me a break."

    Ok. Take five. ;-D

  • wbralick
    18 years ago

    dvd - is there any reason you can't re-route the conduit?

  • brickeyee
    18 years ago

    Drywall does not introduce aenough load to be an issue.
    Under any code.
    The only issue is ensuring the nails have enough hold to make sure the whole thing stays up.
    Scabbing lumber to the side of the joists would be a better option since this places the nails in shear, but even in tension there will not be any problems.
    None of the codes require anything speical for extra layers of drywall, let alone spacing a single layer down.

  • logic
    18 years ago

    "None of the codes"

    Again, you may indeed be correct. But again, there is no way to know that for certain (its a BIG country), and there are a lot of towns out there with their own code...some of it idiotic.
    That said, the OP is better served checking to make sure. No harm, no foul.