Garage Fire Wall - Separation Wall - Something That Your Life Might Depend On

Having a garage attached to your property is very convenient. However, since we sometimes use the garage to perform not necessarily safe "experiments", and store various flammable materials in that area, the wall separating living quarters and the garage (including wall penetrations) must comply with some important rules.

1. Garage entry door to the house - it needs to be a solid door, wood or metal, with a proper weather stripping to create an air tight barrier between the garage and a living quarters (by law, the door should have at least 20 minute fire resistance rating - no hollow core, interior type doors like the ones that you normally install in bedrooms, closets, bathrooms, etc.). One more feature that I always recommend to my clients, and one that has been required on a new construction in many jurisdictions for several years already, is a self closing door. I don't think that any local code enforcement division would force a homeowner to upgrade it if it is an older home, and an original (old) door, but I personally think that it makes sense to do such an update for your own sake. It is a very small investment (around $20.00), and all you need to do is replace a couple of regular door hinges with a spring type and a well adjusted door that will fully close automatically. It is for your own safety ... I know that nothing bad ever happens to you, but just in case somebody forgets to turn off the car engine and leaves the door between the garage and the living quarters open ... you won't smell Carbon Monoxide ...

2. The entry door from the garage into the house should be slightly elevated / higher than the garage floor surface. Many building codes require a step (or curb) between the house door and the garage floor. The step (min 4" recommended, but check your local code) prevents spilled gasoline vapors from entering the house and partially protects residents from carbon monoxide fumes.

3. Garage firewall / separation wall - it would again apply only to the house attached garages. The whole idea is to give you an extra hour of protection (separation wall between the garage and the house is currently required to provide one hour of fire resistance) from the fire that might start inside the garage. In order to achieve this rating, the wall needs to be sheathed with at least 5/8" drywall on each side (from the garage and home side), but check with your local code enforcement division ... some jurisdictions will double that thickness. The separation wall should have no missing / damaged drywall sections, any penetration must be sealed (fire rated caulking would be perfect for small gaps around the pipes, air ducts, door frames, etc). If the wall is made out of brick, cinder block, stone, solid concrete, or any other non-flammable material, you'd just have to worry about penetrations.

4. A forced air heating system distributing air through the house can not have any registers (supply or return) in the garage - older homes often have them, which should be removed and the air duct opening sealed with sheet metal and fire rated caulking. Walls of the metal air ducts exposed in the garage area should be at least 26 ga. steel, no plastic or aluminum (thin wall or flexible type) vent hoses penetrating the separation walls are permitted - if there's no other way to run those vent pipes, box it out and finish it with 5/8" drywall (Type X, taped).

5. An electrical box installed in the garage should not have another one connected to its back (back to back installation) and open inside the house. Also, some jurisdiction might not allow having an electrical panel installed inside the separation wall.

6. Attic access from the garage - keep it closed, no matter if this is a separation / fire wall or not (garage attic might not be connected to the house attic or house walls). Even if the garage attic is completely separated from the house attic or house walls don't back-up to it, open access creates a vacuum. In case of fire inside the garage, this vacuum will suck it in into the attic. Typical garage attic access (at least in the majority of Chicago land homes including new construction) is a square drywall section, usually set on the four pieces of trim. Drywall is fine, but the trim neither provides a proper seal nor has a required fire rating ... it would most likely burn within a few minutes, but I guess it is OK since everyone is accepting it ... Another "gap" in the firewall is a pull-down type staircase to the attic - most of these have only a 1/4" paneling sheet installed and rarely provide proper seal along the opening - have your local code enforcement division comment on it if your garage attic opens to the house attic space.

Many older homes do not comply with those requirements, and of course - I'd highly recommend to do all of the necessary improvements - it's better to be safe ...

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