by Andrew Getty
The state building and fire codes have required a ‘rated’ separation between the garage and house for a long, long time… well before the adoption date of the Uniform Fire Protection and Building Code of 1984.
Here are some of the state codes regarding the basics of fire separations and floor.
Openings from a garage directly into a room used for sleeping purposes shall not be permitted.
Other openings between the garage and residence shall be equipped with a 3/4-hour fire-protection-rated door assembly equipped with a self-closing device.
Glass in the door is okay… if the glass & door is fire rated.
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) sheet steel and shall have no openings into the garage.
This applies usually to forced hot air systems. The air in the garage shall not mix with the air of the house.
The garage shall be separated from the residence and its attic area by horizontal or vertical fire rated separations.
The partition assembly shall have a 3/4-hour fire-resistance rating.
Exception: In lieu of providing partitions that have a 3/4-hour fire-resistance rating, one layer of 5/8-inch thick, type-X, gypsum board may be installed on the garage side and one layer of 1/2-inch, type X, gypsum board may be installed on the opposite side.
Typically sheetrock is used, but there could be other building materials that provide approved, rated separations.
Where horizontal construction is used to separate the garage from the living space or its attic, such construction shall be protected with one layer of 5/8-inch thick, type X, gypsum board.
Openings in horizontal separations shall not be permitted except where the residence is otherwise protected by vertical separations.
Where the horizontal separation is a floor-ceiling assembly, the structure supporting the separation (walls, post, beams) shall also be protected by not less than 5/8-inch (15.87 mm) type X gypsum board or equivalent.
Garage floor surfaces shall be of approved noncombustible material.
The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain OR toward the main vehicle entry doorway.
Only commercial applications require that the floor drain be connected to an approved oil separation system.
Carports shall be open on at least two sides.
Carport floor surfaces shall be of approved noncombustible material.
Carports not open on at least two sides shall be considered a garage and shall comply with the provisions of this section for garages.
Exception: Asphalt surfaces shall be permitted at ground level in carports.
—
Although the above was not a “cut and paste” version of the state code, it does cover the basics.
Commonly some people assume they need two layers of sheetrock on the ceiling if there is living space above the garage… Not so, only one layer of 5/8” Type X sheetrock, taped and finished (for a smoke tight seal) is needed.
All too often contractors do not realize that the inside of the common vertical wall (garage to house) also requires Type X sheetrock, however only 1/2”… 5/8”X on the garage side, 1/2”X on the house side.
Another common misunderstanding is the garage floor drain. In a single family dwelling, a floor drain is not mandatory.
There are however two options. One, use a floor drain and pitch the concrete to that OR; no floor drain and pitch the concrete to the door to facilitate drainage to the outside.
Either way is okay without the need to go through an oil separator.
Only in commercial applications are floor drains mandatory to connect to approved oil separation devices.
This should be clearly discussed between the customer and contractor before the floor concrete is placed.
Questions regarding the code requirements may be directed to your local code authorities.