In this post I’ll talk about some of the safety considerations related to an attached garage. When coming home from the store, with a car full of groceries after a long day at work, it’s pouring rain, there is noting better than having an empty garage bay sitting there ready to protect you from the elements so you can comfortably unload your haul from triple coupon day at the grocery store. Attached garages are often a “must have” when it comes to looking for a new home, but are often overlooked when it comes to its safety as it relates to the rest of the house. As with all of my post this is not meant to be an all encompassing article about attached garage conditions, and safety requirements. Rather it is to outline the concerns related to keeping dangerous gasses and fire contained within the garage and limiting their spread to the rest of the home. The attached garage is just another example of the value a home inspection performed by a professional home inspector provides, and the peace of mind knowing the dangers and how to prevent them.
Keeping unwanted gasses and fumes out of the house
Have you ever noticed that, even in a home with the garage on the main level of there usually is a step going up into the house. This is for good reason, Gasoline fumes and other explosive gases are heavier than air, and they will accumulate at ground level. Their entry beneath a door will be slowed by an elevation increase.
Carbon Monoxide (CO) is going to be present in an attached garage that is being used to park vehicles, there is no way around that. Doors should have tight seals around their joints to prevent seepage of fumes into the living areas of the house. CO, with the same approximate density as air (and often warmer than surrounding air), will easily rise above the base of an elevated door and leak through unsealed joints.
Fire containment
Maintaining a fire separation between the garage and the living space of the home will provide your family with more time and a safer environment to safely exit the home in the event of a fire. It will also slow the spread of the fire to the living space, and decrease the damaged done to the rest of the home and its contents. Professional home inspectors will evaluate and report on the fire separation of the attached garage. Below are examples of what will be evaluated. It is important to note that some of the following examples are referencing IRC code and may not be consistent in every regard with the adopted and amendments to the adopted code in your area.
- Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No. 26-gauge (0.48 mm) steel sheet or other approved material, and shall have no openings in the garage (no return air or supply registers in the garage).
- The garage shall be separated from the residence and its attic area by not less than 1/2-inch (12.7 mm) gypsum board applied to the garage side. Garages beneath habitable rooms shall be separated from all habitable rooms above by not less than 5/8-inch (15.9 mm) Type X gypsum board or equivalent. Where the separation is a floor-ceiling assembly, the structure supporting the separation shall also be protected by not less than 1/2-inch (12.7 mm) gypsum board or equivalent. Garages located less than 3 feet (914 mm) from a dwelling unit on the same lot shall be protected with not less than 1/2–inch (12.7 mm) gypsum board applied to the interior side of exterior walls that are within this area.
- Openings from a private garage directly into a room used for sleeping purposes shall not be permitted. Other openings between the garage and the residence shall be equipped with solid wood doors not less than 1-3/8” (35 mm) in thickness, solid- or honeycomb-core steel doors not less than 1-3/8” (35 mm) thick, or 20-minute fire-rated doors.
- Doors between the garage and the residence shall be equipped with a self closing device.
Conclusion
Outlined in this post are just a few of the numerous conditions that could be present in your garage. Often times an inspector may point out several issues that need addressing, and that can be overwhelming, it is important to remember, anything in, on, or around a house can be fixed. The intention of a quality home inspector is never to scare you or point out reasons you shouldn’t buy a particular house, rather it is to arm you with as much knowledge as possible for you to decide if this is the right house for you, and to keep you safe. For, often times less than the cost of one months mortgage payment, a qualified home inspector will perform a comprehensive home inspection and report to you all the information needed for you to make the best, and most informed decision on, likely the largest monetary investment of your life.
Below is a video of the benefit of having a proper fire separation between the attached garaged and the living area.
