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Dovetail Greene
Dovetail Greene, General Contractor
Category: Home Improvement
Satisfied Customers: 373
Experience:  Licensed Building Contractor & Certified Building Designer
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Can someone advise what dimension lumber would be required

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Can someone advise what dimension lumber would be required to carry a ceiling of double sheet rock across a 12-13 ft span using 1/2 rock for each layer?


My name's Kel.


Are these joists just supporting the ceiling or is there load from a floor from above?

If there's load from a floor above, what's it used for?

Are there any partitions or walls bearing on it?

Customer: replied 3 years ago.

This would basically be a drop ceiling, carrying none of the above weight, just sheetrock, screws and glue. This is an older house with balloon framing so I plan to tie the joists directly to the ouside walls studs as was done with the original studs.


the question about walls or partitions was about the floor above, since this is not carrying weight, doesnt apply correct?


You are correct. Since it's a dropped ceiling don't have to factor in floor, wall or partition loads.


Assuming you're using Spruce Pine Fir #2 & Better

if you frame @ 16" on center using 2x10 you'll keep the deflection or sag to a minimum.


If noise is an issue

you might seal all penetrations and add insulation to deaden sound.


Have I answered you question?

Customer: replied 3 years ago.

I think I'm almost there. When you mentioned deflation and sag, are you referring to joist sag or the 1/2 drywall sag that could occur from spanning more than 16" ?


I could go with 5/8 to increase the distance between joists, and you're correct this is a sound proofing concept so 5/8 would benefit me there as well.

I was referring to the joists sagging.

Highly recommended to frame 16" OC. That will keep the joists from sagging too much and the 1/2" drywall won't belly.

Customer: replied 3 years ago.

Ok thanks. I didn't realize the distance between joists affected how they might sag in the center of a given joist. I thought that had everything to do with the dimension of a joist, and how far it spaned unsupported.

The distance between joists is critical.

The fewer the joists the more each one works.

The more it works the more deflection or sag there'll be.


Dovetail Greene and other Home Improvement Specialists are ready to help you
Hello again KD. This's Kel checking I to see how the ceiling project's going. . .

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