Steven L. Smith, Bellingham, WA Home Inspector (King of the House)

head_left_image

An Attached Garage is Not a Fire-Rated Assembly -- Despite What You Might Have Been Told

I hear the remark, even from home inspectors, that the garage is not fire-rated or 20 minute fire-rated. Home inspectors are not code inspectors, but this kind of talk is based on codes and a misunderstanding of residential code requirements. Let's look at garage/house separation requirements. The book, Building Code Basics: Residential, was published, in part, by the IRC  (International Residential Code) which dictates most of the codes that apply to modern construction. Codes may vary from one jurisdiction to another. Below (bold) are explanations, from the IRC, that apply to garages. Below that are my comments.

"Dwelling separation from garage -- Unlike separations between dwelling units, the separation between a residence and the garage, attached or detached,  is not a fire-resistance rated assembly.  Likewise, penetrations through the separation are not required to meet the rated penetration requirements for fire-resistant assemblies. "

Interpreted: Dwellings that are connected to one another, such as condos or zero-lot-line structures or townhouses, require a fire-resistance rated assembly between the various units. However, the garage at a residence does not have the same requirements.

"Attached and detached garages, within 3 ft of the dwelling, require installation of 1/2" gypsum board on the garage side to provide "limited resistance" to the spread of a fire.  When there are habitable rooms above the garage, the code requires the installation of 5/8” type X gypsum board on the garage ceiling and the bearing wall supporting the ceiling framing requires the application of 1/2" gypsum board on the interior surface. Garage floors must be noncombustible." 

 

Interpreted: The proper terminology, in the case of garages, is "limited resistance to fire" and that is way short being a fire-rated assembly. Simply installing suitable drywall (often referred to as Sheetrock) in appropriate locations, will go a long way toward providing "limited resistance to fire." At any shared walls (garage to house), a noncombustible surface or drywall must extend from the floor up to the underside of the roof sheathing.  When there is a habitable room over the garage, or if the attic over the garage leads into the attic over the dwelling, a noncombustible surface or drywall must be installed on the garage ceiling and on the bearing wall that supports the ceiling framing. The flammable attic access cover, in the photo above, is a breach of fire-resistance if there is a bonus room over the garage or if the garage and house attics are connected. The garage floor, most of the time, consists of a concrete slab. If that is not the case, then the floor must be noncombustible.  

"Doors between the dwelling and the garage also provide some resistance to fire but they do not require a fire-resistance rating. Any one of the following types of doors satisfies the separation requirements:  1 3/8" thick solid-core wood door; 1 3/8" thick solid-core steel door; 1 3/8” thick honeycomb-core steel door; listed door with a 20 minute fire-resistance rating."

Interpreted: The door must be suitable for the purpose, but it need not be fire-rated -- even a wood door is acceptable if it is thick enough. Here is another requirement: There should be an operational self-closing device on all garage/house doors. The garage-house door, in the photo above, is standing wide open. That is a problem.

 

 "Openings from the garage into a sleeping room are prohibited."

Interpreted: That rule is self-explanatory -- doors or windows from the garage, any openings, cannot lead into bedrooms.

"The IRC requires, minimum, # 26 gauge sheet steel for ducts in the garage as well as ducts penetrating the walls or ceilings that separate the dwelling. Ducts are not permitted to open into the garage. Other penetrations, such as steel or plastic pipe, require only that the space around the penetration be filled with approved materials, such as fire-resistant caulking."

Interpreted: Ducts that pass through the garage must be made of steel and ducts cannot open into the garage. B-vents, conduit and pipes that go through walls or ceilings should be sealed, around the penetrations, with fire-resistant caulking. The duct at the garage furnace, in the photo above, is not an acceptable installation, nor is it acceptable to have that hole around the conduit at the garage/house wall.

 I am not downplaying the need to design a garage in a manner that ensures safety, but the proper terminology, to be accurate, is not "fire-rating" or "fire-rated." The proper wording is "limited resistance to fire."

Steven L. Smith

If you enjoy nostalgia and music of yesteryear, click on Elvis' gold record to visit This Day In History. To explore The Stories Behind The Music blog posts click on the electric guitar. 

 

        

 

 

 

 

Comment balloon 5 commentsSteven L. Smith • November 29 2011 07:15PM
An Attached Garage is Not a Fire-Rated Assembly -- Despite What You…
share
I hear the remark, even from home inspectors, that the garage is not fire-rated or 20 minute fire-rated. Home inspectors are not code inspectors, but this kind of talk is based on codes and a misunderstanding of residential code requirements. Let's… more
Get Off The John -- So I Can Inspect It!
share
They follow me everywhere, I cannot get away from them. This last week I had to work with, and around, five house destroying organisms at various residences in Bellingham and Whatcom County. Their stalking me might have been revenge for the widely… more
Happy Thanksgiving from King of the House Home Inspection
share
On behalf of the King of the House staff, I would like to wish all of my ActiveRain friends, and my associates in Bellingham, a great Thanksgiving and a holiday season. I was reading an editorial today, in the newspaper, that claims that the period… more
Whatcom County Home Inspection (King of the House) Knob and Tube…
share
In the last week, half of the home inspections that I performed in Bellingham were at houses with knob and tube wiring systems. The minute I say that, the inspectors know that the houses I inspected were at least 50 years of age. Knob and tube… more
Washington Home Inspector Training Course -- February 6, 2012
share
Wow, how this year has been flying by. The schedule has been released at Bellingham Technical College and it has been announced that the next home inspection training course will begin on February 6, 2012. The BTC offering, the first such course to… more
Whatcom County Home Inspections (King of the House) Crawl Space Water
share
In the wet Pacific Northwest, an ongoing problem is trying to inspect crawl spaces that have an abundance of crawl space water or flooding. The concern is, at the least, three-fold. First, the water should not be down there and it is conducive to… more
Short URL Tool for Google Maps
share
This information might save time, and be handy, for any ActiveRain real estate professionals who send, or post, URL's or links to Online maps. In the majority of the home inspection reports that I send out in Bellingham and Whatcom… more
Consumer Alert -- Outbreak of House Destroying Organisms (HDO's)
share
Just when people thought it was safe to get back into the housing market, it has been revealed that many houses in the USA are vulnerable to, and being subjected to, serious infestations by House Destroying Organisms. Inspectors have, for years,… more
Better Safe Than Sorry (King of the House) Bellingham Home Inspections
share
A couple years ago I tossed one of those orange safety or hazard cones in the back of my truck. Somewhere along the line, at one of the Washington State Home Inspector Licensing Board meetings, a member made some mention that such a cone could be… more
Whatcom County Home Inspection (King of the House) Sometimes it is…
share
Often, in the course of doing home inspections in Whatcom County, detecting or locating a problem can be difficult and require lots of perseverance and utilizing one's powers of deduction. But, and it only seems fair, sometimes we get lucky and do… more