This house was built in 1981. The fire wall between the garage and attic is made of one layer of sheetrock and studs turned sideways. Looks funny to me, anyone know for sure?
Thanks
Hi Louis,
I am not too concerned about the sideways 2x4’s as they are just being used as nailers for the sheetrock, however you picture does not show whether the drywall is taped and mudded as it should be.
Regards
Gerry
There is nothing wrong with the two by fours in that position, it matches a gable end construction of a typical dwelling framing.
One layer of 5/8" drywall, though will not give this separation a 1 hour rating.
Two layers would be needed. One on each side.
Tape and joint compound will also make it a smoke barrier along with a fire barrier as Gerry mentioned.
More information can be obtained by logging on to GP, and USG sites which will give you all the information you want on drywall products and their uses.
Hope this helps.
Marcel
In some municipalities, within this market area, Double 5/8 Firerock installed on one side with overlapping seams meets the criteria of fire separation.
Gerry:
Sometimes the local AHJ makes no sense.
I can vividly recall installing Hat Channel with a 22 caliber Hilti gun to secure 5/8 firerock to a 10 inch Masonry Block wall (10-14 foot high and extending 150 feet) to meet the fire code of a local municipality.
The recoil of quite a few masonry rounds/loads leaves a memorable impression.
Sorry Joe, but I have to disagree.
The typical 1 hour protection is achieve with a 5/8" gypsum board on both sides or it can also be acheived by using a 5/8" layer with a 7/8" furring channel and an addittional layer of gypsum drywall to that.
Check out the UL listings on this product.
Marcel 
Hi Joe, many times the AHJ makes no sense, what passes for a fire wall in many locations is rediculous, as for the Hilti, I hear you (or rather i would if it wasn’t for the tinnitus) I gotta run and answer that phone 
Regards
Gerry
Marcel,
Joe H is correct.
Also, some municipalities only require a 45-minute burn through rating, not one hour.
Marcel:
Pennsylvania did not have a Building Code until July, 2005.
One also has to remember that Building Contractors (Carpenters, Plumbers, Electricians, etc…) are not Licensed (Past or Currently) in the State of PA.
Joseph;
I was in Lancaster once, and I enjoyed it very much. Is that where you are?
Now I know why you are so far behind. ha. ha. 
Marcel
Hi Everyone,
Just joined the Forum today. I have had some weird experiences myself with Firewalls. Gypsum based board on the living space side of the studwork as normal, but OSB on the Garage side. Looked very pretty, but not technically correct i believe !!
Any comments??
Terry
Hi Everyon,
YES I AM A MEMBER OF NACHI, MAYBE I FOLLOWED THE WRONG PROCEDURE TO REGISTER.
Anxious to find out about your weird experiences about the firewalls.
Marcel
Hi, Terry, welcome to the BB.
You were right it was not done correctly for a fire rated wall.