This article focuses on three important safety issues regarding attached garages: inadequate fire separation, doors connecting the garage and the house, and exposed combustible insulation.
A reminder about codes: Although we do not refer to code requirements in this review, having knowledge of these is useful so that, unless you have a good reason to differ from them, your recommendations will be consistent with code requirements. Your recommendations should make clear the reasons for and the implications of your comments. Codes vary from place to place and change regularly. Many different codes apply to homes and most are not retroactive, so current code requirements often do not apply to existing homes. Codes may become more or less restrictive over time. It is very complicated!
Fire Separation in Attached Garages Attached garages create a potential fire exposure to houses. Automobiles, gasoline and other combustibles typically are stored in garages. According to the U.S. Fire Administration, “Garage fires tend to spread farther and cause more injuries and dollar loss than fires that start in all other areas of the home.” There are more than 6,600 garage fires every year. As home inspectors, we look for a fire separation (not a fire-rated assembly) on walls and ceilings between the home and garage.
Automobile exhaust fumes often contain carbon monoxide and it makes sense to keep these gases out of the home. We also look for gas tightness between the garage and home.
Dealing with the ceiling: Ceilings are treated differently depending on whether there is living space above the garage. The illustration at the top right on this page outlines typical approaches, but keep in mind that you usually cannot determine the drywall thickness and if the drywall is painted, you won’t be able to identify the type. Inspectors typically focus on continuity of the ceiling, looking for damage, unsealed penetrations and openings.
Pull-down stairs: Pull-down stairs in a garage ceiling may breach the fire separation unless the stairs were specifically designed. If the main panel is plywood, there is probably not an effective fire separation.
Ineffective fire separation is a result of one of the following:
- poor design or original construction practices (including missing components or inappropriate materials);
- mechanical damage (often a result of vehicle impact);
- moisture damage.
Garage ceiling penetrated by central vacuum system.
Heating and cooling ductwork: There should be no supply or return registers in the garage, and no gaps in the heating and cooling ductwork. The goal is to prevent automobile exhaust fumes from entering the home. (Openings also can be related to issues of heat loss or gain.) You might find this situation when inspecting a home in which someone uses the garage as a workshop. Ductwork in the garage also should be insulated to levels that are appropriate for your area.
Look for supply or return registers in the garage.
Doors Between the House and Garage (Man Door) No door between garage and bedroom (sleeping room): A garage fire may quickly kill a person sleeping in an adjacent room. Sleeping people are far more vulnerable to asphyxiation. That is why there should not be a door between the bedroom and the garage. Homes are not typically built this way, but remodeling projects can create this adverse condition.
No door allowed? Some communities do not allow doors between the garage and home.
Tight-fitting fire door with self-closer and a step-up into the home: Doors between the house and garage may breach the fire rating or gas tightness if they are not the proper type or if they are not properly installed. The doors should be tight-fitting, made of solid wood or steel, be 1 3/8 inches thick or have a 20-minute fire rating. (Note: The 2012 IRC does not require a fire-rated door.) In our opinion, the door should be weather-stripped and self-closing. In addition to providing fire safety, having this type of door also reduces the chances of vehicle exhaust from entering the house. (Note: Self-closers may not be required in your area, or they may only be required in new construction or as part of a 20-minute fire-rated door assembly.)
Things to Watch for
- Make sure the door from the garage does not open into a sleeping room.
- Where a fire-rated door is needed, look for a rating plate on the edge of the door or frame.
- Test the door operation. Where there is a self-closer, does the door close securely by itself?
- Look for gaps around the door. Does it fit tightly?
- Report pet doors or other door openings.
This steel garage-house door has no self-closing device.
The pet door defeats the fire separation.
Exposed Combustible Insulation in Garages Exposed foam plastic insulation is a fire hazard. This insulation contributes tremendous fuel and toxic gases to a fire and can make the difference between a controlled fire and a complete loss. Plastic foam insulation should be removed or covered with a noncombustible material such as drywall.
Exposed foam insulation in garage should be removed or covered.
We have described three safety issues for attached garages. In the ASHI@HOME training program, we also cover garage floors, vehicles doors and combustion appliances inside garages. You can read more about conditions, implications and strategies for inspection on these issues.
Thanks to Roger Hankey and Kevin O’Hornett for their help and advice on this article. The first draft had more references to code and requirements of the authority having jurisdiction, but this version addresses the issues from a more practical perspective.