# Why 2 layers of drywall?



## The Coastal Craftsman

I have been working in some houses lately and as well as my own. I have noticed that some rooms have 2 layers of 1/2" drywall. I can't see any reason why they have done this. Some rooms have it and some don't. Really causes hassle as no standard pre hung doors fit. 

Why would they do this? I didn't think much of it until I see some other houses in this area that had the same problem.


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## Leo G

Attached garaged wall per chance?


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## griz

Either has to do with the Fire Code. Are the walls adjacent to a garage? Or the wall finish/drywall surface in all the houses was not acceptable.


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## Rob PA

i have seen some around here do it as the first layer was that far junked and didnt want to pay for rip out


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## Abel

The reason I can think of is to gain a required fire rating, but that was with 5/8" dense glass. When was the home built???


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## Anderson

Fire rating, or guys getting paid by the sheet to hang, my friend had one crew cutting the stuff up and throwing it in the dumpster.


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## Abel

Anderson said:


> Fire rating, or guys getting paid by the sheet to hang, my friend had one crew cutting the stuff up and throwing it in the dumpster.


:no:
Lmao!!!
Wow! That's why measurements are so important.


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## festerized

Either fire rating or one of layers is a sound barrier


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## Anderson

Abel I didn't understand it either, just repeating what I was told first hand.


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## genecarp

I worked for a builder many years ago who used to double rock all his jobs, he would somehow veneer the second layer avoiding most of the normal fastening penetrations , this would eliminate any future nail or screw pops, make quicker work of spackling, and make a wall solid enough that you would think it was plaster. He build only multiple million dollar homes and that's how he rolled, GMOD.


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## rselectric1

I've had instances where in lieu of repairing drywall, they've opt to "skin it" on the last job with 1/4" for a fresh surface. But I haven't run into 1/2" ever on residential.

And yes, the door casing usually has something stuffed in there like scribe or tons of caulk to hide the lapse in judgment.

The only other times I have run into double 1/2" (or more) was on commercial.


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## The Coastal Craftsman

No garage next to these rooms. Only seems to be 1-2 rooms of each house has this. Every other wall is just single 1/2"

Like you guys say could be they got paid per board or finish on walls was not good enough. Its def been like it since the house's were built.


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## festerized

Which walls have the extra layer?
Are these extra sheets in rooms that are back to back?
Could be sound proofing


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## Anti-wingnut

I would think it was for sound proofing, or to repair older beat up walls. As far as a fire assembly, the dry wall association design guide only shows 5/8" rock as a rated assembly, with the exception of some proprietary 1/2" type X. That is not to say that in days gone by, 1/2" could be part of a rated wall.


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## The Coastal Craftsman

Rooms are separated by closets.


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## The Coastal Craftsman

rselectric1 said:


> I've had instances where in lieu of repairing drywall, they've opt to "skin it" on the last job with 1/4" for a fresh surface. But I haven't run into 1/2" ever on residential.
> 
> And yes, the door casing usually has something stuffed in there like scribe or tons of caulk to hide the lapse in judgment.
> 
> The only other times I have run into double 1/2" (or more) was on commercial.


I have only seen 3/8th drywall maybe 2-3 times. Surprised you hardly ever see 1/2" as I thought that was the standard. 3/8th just feels so weak and flimsy.


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## Anti-wingnut

BCConstruction said:


> Surprised you hardly ever see 1/2" as I thought that was the standard.


I'm all commercial. You never see 1/2" except for non-rated layering. RS is in LA. Could be a siesmic thing. 5/8" is much denser and stronger material than your typical 1/2" GWB


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## griz

In high end residential it is not uncommon to see two 1/2"
layers strictly for appearance. Usually where there is a large expanse of smooth wall.


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## CCCo.

How old is the house BC? Curious


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## rselectric1

BCConstruction said:


> I have only seen 3/8th drywall maybe 2-3 times. Surprised you hardly ever see 1/2" as I thought that was the standard. 3/8th just feels so weak and flimsy.


I probably typed that wrong. 1/2" is the standard here too. I was referring to a skin OVER the 1/2". Sum thickness would be 3/4".

Sorry for the confusion.


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