A common mistake that home inspectors make when inspecting single family residences is related to opinions stated about the separation between the home and the attached garage. There comments often leave them "out on a limb" when repairs are called for.
I routinely hear erroneous statements about compromised “fire-rated surfaces” between the house and the garage. Statements declaring that the surfaces between the house and the garage are not “1hr fire-rated,” or that the “1hr fire-rated surfaces” are in some way compromised,are very common in inspection reports. The door or doors placed in this “separation” are also frequently misunderstood and incorrectly reported on.
The wall between the house and the garage---believe it or not---is NOT a fire-rated assembly and is referred to in the code as the “Garage/Home Separation.”
Requirements to meet this “separation” requirement are really quite minimal compared to what would be necessary in an actual “fire-rated assembly” (As would be required between multiple dwelling units like condos, townhouses and duplexes.)
Typically ½” drywall is all that is necessary to meet the separation requirement. If there is living space above the garage, the ceiling would have to be 5/8” type “X” drywall. Again, this is not a “fire-rated assembly,” but merely what is required to meet the proper “separation” requirements.
Regarding the door between the house and the garage, all that is necessary is to install a door that meets the “separation requirements.” There is nothing that says it has to be a “fire-rated door,” as frequently reported by home inspectors. While this may seem confusing, if one looks at the code it becomes clear. It also reveals the source of some of the confusion.
To meet separation requirements, the door must be one of three types of doors: 1. Solid wood door not less than 1-3/8 inches thick, 2. Solid or honeycomb core steel doors not less than 1-3/8 inches thick, or 3. A 20-minute fire-rated door.
The first two types are fairly self explanatory but the inclusion of the third type has lead to a great deal of confusion because a door that is a “20-minute fire-rated door” leads one to think that the doors in general, and thus the walls, have to somehow be “fire-rated.” For a door to achieve a 20-minute fire-rating it has to go through testing procedures by Underwriters Laboratories and then it receives its “UL listing” as a fire-rated assembly. One of the things that are required to meet the requirements to be listed as a 20-minute fire-rated assembly is for it to have a self-closure mechanism. Since door types “1” and “2” do not “require” closure devices it is little wonder that some inspectors conclude that none of the doors require them----even though the type “3” door requires one in order to meets its UL listing. Because the words “self-closure” do not appear in the code, some builders and home inspectors (and even jurisdictional inspectors) mistakenly take this to mean that no closers are required on any type of door between the house and the garage.
Since manufacturer’s requirements supersede code, it is a little disingenuous to conclude that code does not require them.
Required weather-stripping on these doors is covered in other parts of the code both for energy conservation and as a barrier to fumes and combustion by-products.
Hopefully this post will help clear up some of the confusion.
Charles Buell, Seattle Home Inspector