I presently have a 21X31 garage using 2x12 rafter ties spaced 48" apart. I would like to drywall and insulate the garage. If I add 2x10 ceiling joists, spanning the 21 ft just like the rafter ties, could I hang drywall using the rafter ties as additional ceiling joists. This would then give me ceiling joists (2x10 and 2x12) spaced 24" OC which should be acceptable to hang drywall and R30 insulation. Does this make sense and/or meet code? Thank you
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Using garage rafter ties to hang drywall
- Thread starter LouMan
- Start date
ICE
Oh Well
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Yikes
Gold Member
Based on the Table R802.5.1(1) and (2) posted by ICE, it looks like you first need to determine
If you are looking for any more definitive answer that that, you would need to perform calculations instead of relying on a prescriptive table in the code.
- what kind on wood was used for the rafter ties
- the grade stamp on the wood
- whether the attic you have now created is intended to be used for storage or other additional loads.
If you are looking for any more definitive answer that that, you would need to perform calculations instead of relying on a prescriptive table in the code.
The 2x12 rafter ties are Grade #2 Douglas fir. Some light storage (xmas decorations, small totes maybe 20-30 lbs ea, etc.) would be nice but if I'm limited to drywall, insulation and some lighting that would work. Just trying to get a finished, well lit, heated work area. Thanks
Genduct
Registered User
The real concern is not collapse but how much deflection you will experience. Seems since this is a utility space and not living space, any flexing of the drywall will not be an aesthetic concern if you wind up with 1/180
Yep, it might be a little "bouncy "
Yep, it might be a little "bouncy "
Yankee Chronicler
Registered User
I don't understand why you want to use 2x10s. How many additional celing joists are you talking about, and how much money would you save by using 2x10s instead of 2x12s?
The problem with 2x10s is that if you align the bottoms with the 2x12s(which is what you would do if you want to use them to support a sheetrock ceiling), the tops will be 2 inches below the tops of the existing ceiling joists. That means any flooring you put in the "attic" or loft space won't be supported every 24 inches, it will only be supported every four feet. That means you need thicker/stiffer flooring, and it means that whatever loads you have in the attic aren't distributed across all the ceiling joists, but are carried only by the alternate (original 2x12) ceiling joists.
This just doesn't strike me as a good approach.
The problem with 2x10s is that if you align the bottoms with the 2x12s(which is what you would do if you want to use them to support a sheetrock ceiling), the tops will be 2 inches below the tops of the existing ceiling joists. That means any flooring you put in the "attic" or loft space won't be supported every 24 inches, it will only be supported every four feet. That means you need thicker/stiffer flooring, and it means that whatever loads you have in the attic aren't distributed across all the ceiling joists, but are carried only by the alternate (original 2x12) ceiling joists.
This just doesn't strike me as a good approach.