Garages are a part of many homes in the United States. Whether you use your garage to store your car or holiday decorations, or use your shed to store your lawnmower or garden tools, these structures likely are a valuable addition to your home.
The garage is physically attached to the house as an addition. Since this type of garage is part of the main residential structure, it may or may not have habitable living space immediately above it. Because the attached garage is connected to the residential structure, certain measures should be taken to minimize the hazards associated with fuels and fuel exhaust. The walls immediately adjacent to all habitable space should be separated from the residence and the attic areas by at least 1/2 inch gypsum board applied to the garage sides. If living space is immediately above the garage area, there can be no holes or open penetrations in the gypsum board. Some jurisdictions require 5/8 FIRE-X gypsum when used in a garage.
- Garage is totally separated from the living portion of the residence. Detached garages are independent structures, which are typically slab on grade structures. The specifications for the slab on grade structures are generally the same as those for an attached garage or a house. With a detached garage, there are fewer concerns regarding fire and safety hazards than with an attached garage. However, the area is still considered a potential fire hazard. The main concern of this type of garage is its structural integrity.
- The exterior sidings and roof coverings are typically installed the same as any other structure. If the detached garage has a fossil fuel heating system, then the same requirements to elevate the combustion chamber 18 inches above the slab and provide protective barrier apply.
The structure of the garage is very similar to the main house.
- Slab – The slab should slope from the rear of the garage toward the automotive doors to ensure drainage of water, etc. Most cracks in the slab are usually expansion/contraction-related, and for the most part, expected. If cracks are large, exhibit deflection or differential movement such as heaving or settlement, it could be a sign of a serious concern.
- Wall Separation – The living area adjacent to the attached garage should be separated with a minimum 1/2 inch gypsum board. This separation is required in order to prevent toxic exhaust gases and gasoline vapors, which are heavier than air, from entering the residence. Therefore, the walls and ceilings that separate the garage from living space must be free of any holes or voids. If the wall adjacent to living space has a door, the door should be installed with a curb, be self-closing, and the weather stripping should provide a tight seal around the door.
- Roof Structure – The structural requirements and design of a roof should meet the same criteria as the residence. Houses built today typically utilize roof trusses, while older housing employed conventional framing, which are rafters and joists. Ceiling structures of garages are frequently modified to accommodate an access panel or disappearing stairs. This may result in improper modification of the joists or trusses. Headers are needed for conventional framing, and if trusses have to be cut, an engineered reinforcement system may be required. Areas over garages are frequently used for storage of personal items; possibly overloading joists or trusses. The garage attic area should be separated from the residence by a firewall, assuming there is access from the garage into the attic area. The roof structure should not be sagging or putting unnecessary pressure on the outside walls. Generally trusses are engineered and braced individually and as a system, and are typically dependable structures. Conventionally built roof systems are also dependable, however, there are workmanship short cuts that may compromise the roof system (i.e. garages may not have any ceiling joists or adequate ceiling joists). This will put considerable pressure on the outside walls. The rafters may be over spanned, or may not have proper collar ties. Check for bowing at the center of the sidewalls and for excessive roof deflections.
- Framing – The structural requirements and design of the wall framing should meet the same criteria as the residence deterioration is frequently found in garages and around both the vehicle and the personnel doors. Check the bottoms of the jambs, door rails and stiles. The framing may be racked due to the large garage door(s) opening, and inadequate bracing. It is best to look for this racking when you are 25 to 50 feet away from the garage or as you are approaching the garage from the front. The closer you get, the more difficult it is to recognize. Bracing can be difficult, however, an “X” bracing and/or solid sheathing in the inside is generally adequate.
- Door from the garage to the residence – The interior door should have a tight seal all the way around to prevent seepage of exhaust or gas fumes. This door should be fire-resistant, such as metal clad or solid core wood. You may also see 1 3/8” hollow core interior doors with a sheet of metal on the garage side. This may be accepted in many areas, however, its fire protection is negligible. As a safety feature, the door should be self-closing. Many municipalities have requirements for fire-rated doors and frames. Because the door should resist a twenty-minute fire, there should be no glass or other openings in the door itself.
- Fire Step – The slab of the garage should be a minimum of 4 inches lower than the slab entering the house to reduce the potential of gasoline or exhaust fumes from entering the property.
- Water Heaters and furnaces in garages – Water heaters and furnaces in a garage should have the firebox, burners or electrical elements located 18 inches above the slab to reduce the possibility of fire from volatile fumes. A furnace or water heater located in a garage should also be protected with an anti-collision device, such as a steel post with a proper foundation, to prevent an automobile from striking the appliances.
- Garage Doors – Automobile doors should work easily, with little exertion. Overhead/automobile doors should have a lock, unless they have an automatic opener. Check that the weather stripping on the bottom of a garage door is defective or not secured. Fiberboard or pressed board door panels in garage doors are vulnerable to the absorption of moisture and de-lamination. Garage door springs should be protected, so that they cannot pinch an individual’s hands (i.e. they should be near the ceiling). The springs are required to have a safety retainer, such as a cable in the center of the spring so that if the spring breaks, people in the area are less likely to be injured. Cable wires on garage doors should be inspected for fraying or improper support. The tracks should be properly secured and lubricated with heavy grease. Oil or silicone is not as effective as grease. Inspect the rollers for bent shafts, looseness and how they roll in the tracks. Electrical outlets in garages should be installed in accordance with the code. Electrical outlets should be Ground Fault Circuit Interrupter protected, with the exception of dedicated outlets for garage door openers, freezers, etc. Automatic garage door openers:
- Electrical – Automatic garage door openers should be plugged directly into an outlet. Extension cord wiring is not acceptable. The outlets should not be on GFCI protected circuits.
- Auto Reversing Device – The garage door opener should have an automatic reversing device to prevent crushing or damaging an item or person that may be caught beneath the door. The device or clutch should reverse with 50 pounds or less pressure. Many older operators do not have reversing mechanisms.
- Light beams are also effective as door reversing devices. They are usually installed just inside the door at the bottom.
….Probe the sill and other suspect wood to determine if damage is present. This is particularly important in a garage. In some cases, termite companies may inspect a residence, but not the garage.
- Concrete slab cracking, heaving and/or settlement
- Holes or openings in firewalls or ceilings
- Door to residence does not meet fire-spread requirements
- Garage door opener does not reverse or reverse properly
- Extension cord wiring, lighting not operating properly
- Deterioration at garage doors and/or frames
- Garage framing racked, walls bowed and/or doors out of alignment
- Roof framing deflection and condition of the roofing gutters, downspouts and trims
- Condition of the wood sill plates and other suspect wood
- Garage door springs loose or without safety retainer, track and roller operation
- Garage door springs loose or without safety retainer, track and roller operation