Interior Last Updated: Apr 18th, 2006 - 01:01:14


Garage Fire Wall
By John R. Schneider
Mar 23, 2002, 23:26

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 The house we live in has a small kitchen and no laundry area inside.  We would like to add a pantry and laundry area off of the kitchen and we were thinking of using some of the space in the attached garage to do this.  The garage is right next to the kitchen and the plumbing lines for washer and dryer are within five feet.  The area that we would like to add is approximately six feet by 10 feet.  Other than extending the floor into the garage and building the walls to enclose this area, are  there any special requirements regulating something like this?                     S. G., Hayward

 There are special requirements regarding the wall between the house and the garage and they primarily have to do with safety and the spread of fire.  Any time that a garage is attached to a house, the building code requires that the wall separating the two portions of the building,  be constructed with a fire rated surface on the garage side of the wall.

Studies have shown that the chances of fire starting in a garage are much greater than a fire starting in a house.  The reason for this is that garages are used not only to park vehicles, but also to store  personal belongings, paint, cleaning supplies, tools and equipment.  Many garages also contain gas fired appliances, such as the water heater and furnace serving the house.  Anytime that combustible material and appliances or vehicles that burn gas are stored in the same area, there is a great potential for fire.

Although the building code does not have any specific control over what people store in a garage, or how they store it, the code does regulate how a wall between the house and the garage will be constructed to resist the spread of fire.  This wall is often referred to as a "fire wall".

A "fire wall" in residential construction is a wall that is covered (on the garage side) with sheetrock that is 5/8th of an inch thick.  Openings in a this fire wall are usually limited to a door, or installation of an electrical sub panel.  Any door located in a fire wall must be solid core, at least one and three-eights of an inch thick,  and self closing.  Basically, no other openings in the wall are allowed.  This construction will allow a fire to burn in a garage for approximately 20 minutes before it can burn through the wall and into the house.

Building a room into the garage would require that the walls of the addition (on the garage side) and any other openings the addition may create, be provided with this fire rated surface.  This includes the ceiling of the addition and around the raised portions or underside of the floor.  All joints serving the sheetrock on the fire wall must be covered with sheetrock tape, and sealed, or filled with a fire resistive caulking.  The door opening into the garage must be provided with the type of door mentioned above.

One important consideration that you must address before you begin to build this addition into the garage is whether or not there are any restrictions in converting this space.  Most cities require that at least two, covered, off street parking spaces be provided for each residential structure.  Building a room into the garage may eliminate this requirement which could make the room illegal.  If this were the case, the city could make you tear it out.

 Unfortunately there are no specific size requirements for residential garages mentioned in the code book to provide guidance for a situation like this.  Most two car garages are approximately 20' x 20'.  How much of this space is actually necessary to park a vehicle would be up to an individual city to decide.

 If you are planning for this to be a permanent structure, I would suggest that you consult with your local building department to determine how much of a projection into the garage they would allow.  It is much easier to make changes now on your plans, than it would be to tear down a room once it is constructed.  Good luck with your project.

John R. Schneider is a licensed general building contractor and a certified residential code specialist. He is president of All About Homes, a residential inspection company, and has been performing code and construction consultations since 1985.  Readers may address their comments to John Schneider, 24326 Mission Blvd. Suite 7, Hayward, Ca 94544.  Fax number: 510 537-8666. Schneider will answer questions of general interest in the paper. He reserves the right to edit the letter for brevity and clarity. Readers are encouraged to contact a competent contractor or code consultant for specific information regarding questions they may have about their homes.

Copyright 2002, John R. Schneider, all rights reserved



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