Garage Fire Separation From House

[Joe Arcaro]

Hi:

Code says that required fire separation from house and garage must be 1/2" drywall or equivalent.

Is OSB panels equivalent?

House built in 1999.

Thanks,
Joe

[Gunnar Alquist]

Hi:

Code says that required fire separation from house and garage must be 1/2" drywall or equivelant. Is OSB panels equivelant? Thanks, Joe

No. I think plaster would be equivalent.

[Jerry McCarthy]

Presto Logs? Just kidding - :D Gunnar's correct.

BTW, IMHO it was a silly change. It couldn't be that the NAHB had anything to do with it? Just asking.

[Jerry Peck]

Code says that required fire separation from house and garage must be 1/2" drywall or equivalent.

Is OSB panels equivalent?


It is not "fire separation", it is simply just a "separation" wall. Throwing in the term "fire" implies that it may be a "fire wall", which it is not.

And, no, OSB is not equivalent ... unless the OSB was FRT, in which case someone would need to certify that it was equivalent. Could you have OSB backing on the wall and gypsum board over it? Sure. :)

The IRC skirts around the "fire" separation issue by simply calling it a "separation" wall, yet, when cables, conduit, pipes, etc., penetrate through that "separation" wall, those items "shall be protected by filling the opening around the penetrating item with approved material to resist the free passage of flame and products of combustion", which implies the are dancing around the term "fire" quite closely. :D

[Garry Sorrells]

Is the OSB fire rated????? Could not see any stamps in picture.
Drywall has a fire rating, as is sheet metal, brick, etc.

[H.G. Watson, Sr.]

Are these SIPs?

[Jerry McCarthy]

I agree with EC Jerry about the so called "fire separation" designation. However, the California Residential Code and IRC do not. :mad:

[Thomas Randall]

When did fire separation walls begin to be required and would plaster in a 1965 house count as fire separation or just separation?

[Jerry Peck]

When did fire separation walls begin to be required ...

There were many different variations of the garage/carport "separation" walls in the past, and many existed at the same time. Some were referred to a "fire" separation walls using various terms, but few (if any) were true "fire-resistance rated" walls which actually were constructed to any fire-resistance rated wall design, most were nothing more than an assembly of components used in fire-resistance rated wall construction. For example, the garage side was required to be Type X drywall on the garage side, but not on the house side, and the electrical membrane penetrations were sometimes required to be protected (but most of the time were not so required).

The simple answer is that this "separation" wall when through a lot of growing pains as different people tried to understand and describe the actual purpose of the wall. What we have today is that most acknowledge that this wall is simply a "separation" wall and is not a "fire-resistance rated" wall.


... and would plaster in a 1965 house count as fire separation or just separation?

In some AHJ, yes, in other AHJ, maybe not.

Question, is the plaster on the garage side too, or just the house side? The key is what is on the house side, and what openings are in that wall (including any doors or windows, ductwork, etc.).

[Thomas Randall]

Jerry, thank you for your input.


The plaster is garage side. It appears to be a skim coat over a drywall backing. On the house side there is drywall but also open framing in one small area behind some stairs (split entry home).

There are penetrations that have been filled with expanding foam (I will be calling for something more appropriate and the door to the living space is more than inadequate (hollow core, not self closing).

It seems I should make my references to the 'Separation Wall' and not to a fire rated one.

[Door Guy]

I think the reason it's call a separation wall instead of a firewall is because a firewall requires a design and should be UL rated. A design should be done by a qualified designer, not a contrator. Most residential construction does not require sealed drawings. My opinion is that it's the codes way of getting some protection without the wall needing design and testing. Any other opinions?

[David Miller]

Could you have OSB backing on the wall and gypsum board over it? Sure. :)


What about OSB over drywall?

[Jerry Peck]

What about OSB over drywall?

Nothing says you can't try to burn your house down another way if one way is not allowed ... :)

If the OSB catches on fire, the 1/2 gypsum is still there to protect the separation for the same amount of time as it would have before.

Just like when installing "fireblocking" ... wood is used for that purpose, 2x wood, 2 layers of 1x wood with the joints offset, 1/2" gypsum, 3/4" plywood with 3/4" plywood over any joints, etc.

The 1/2" OSB would actually help delay the fire from burning through the separation wall, but ... when the OSB becomes fully on fire, that would be a detriment, hopefully, however, the people has had time, even more time, to escape.

I was having a conversation about EEROs with someone and realized that not only does EERO stand for Emergency Escape and Rescue Opening, but it also stands for Emergency Escape or Recovery Opening as it could be used for that purpose too ... although Emergency Escape and Rescue has a much better sound to it ...