3/8 vs. 1/2
 

basic question: is 3/8 used for ceilings while 1/2 is used primarily for walls?

thanks

No, 5/8 for ceilings.

3/8 can be used for curved walls or on repair work. It can also be applied directly over plaster.

why is thicker/heavier used for ceilings? i would expect it would be better if it is lighter.

5/8 is thicker/heavier/more ridged. 3/8 will sag between every rafter.

thanks. makes perfect sense now.

3/8's should only be used for strange repairs and curved walls. Everything else should be 1/2" or 5/8"s.

PS.

1/2" is perfectly fine for ceilings, if your joists/trusses are 24" on center you need to use 1/2" CD board.

5/8" is good for everything but then there are drawbacks, such as cost, more work to install, acoustically it will change the way a room sounds and if used on both sides of a wall it may cause difficulties with trimming your doors.

1/2" is acceptable on ceilings if framing is 16" o.c., 5/8" for 24" o.c. framing.....

Unless there is a requirement for a fire rating or some other assembly. SFR's using TJI's will often be required to use 5/8" type X drwall because engineered lumber burns much more rapidly than nominal sawn lumber. Some areas have recognized the use of fire rated 1/2" GWB, but this is not universal

I'm sure that BJ knows this

Do you not have "CD" board in your area? 1/2" CD board is designed for 24" spans.

As for fire ratings, that's a seperate issue and code specific to different areas.

Dan

Just for reference, I used 3/8 on my garage walls, and it seems strong enough. I know...lots of people don't recommend it, but it worked, it's lighter, and cheaper, and it was just my garage.

Cheaper? I think not. At least not in cost. It is a cheaper (inferior) product though.

Funny thing is, as per modern fire ratings, you should have used 5/8 Type X or 1/2 fire rated board in your garage.

I'm sure that's what they used for the exterior walls of the house. I just finished the rest of the garage.

The garage is the most flammable spot in the house