Author : Building Code Trainer
Is a Garage Floor Required to be Sloped?
If a garage is used for parking vehicles, its floor is required to be sloped per the International Residential Code (IRC).
Although there is no specific slope mentioned most experts will agree that a slope of 1% or higher is acceptable.
To understand where this requirement is coming from and why a garage floor must be sloped, let us look at Section R309.1 of the 2021 International Residential Code (IRC).
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.
Why Must a Garage Floor be Sloped?
First off the code section above starts off by saying the surface of a garage floor must be of an approved noncombustible material, such as concrete.
Then when we read on we can see that the area of the garage floor used to park vehicles must be sloped. The reason for this is to help facilitate the movement of liquids.
This can be done by sloping the garage floor to a drain or towards the garage door entry. This allows any type of flammable liquid, grease, oil, or other hazardous material that might leak from a vehicle to drain away from the garage instead of building up onto the floor.
It is important to note that this section of the code only applies to private garages that are subject to the International Residential Code. Floor surface requirements of public and private garages subject to the International Building Code shall comply with Section 406.2.4.
Fun Tip: To learn the difference between the International Residential Code (IRC) verses the International Building Code (IBC), be sure to check out this POST.
This sums up the basic code requirements of garage floor slopes that are subject to the International Residential Code (IRC).
For more information on garages subject to the 2021 International Residential Code, be sure to check out Section R309 of the IRC.
- Garage floor surfaces shall be of an approved noncombustible material.
- Garage floors used to park vehicles shall be sloped to facilitate the movement of liquids to a drain or garage door entry.
Related Articles to Read:
- Are Vapor Barriers Required Under Concrete Floors?
- Fire Rated Door Requirements Between a Garage and House
About the Author
Building Code TrainerAuthor
This site is run and maintained by a Certified Building Official, Plans Examiner, and Inspector. With a Bachelors of Science Degree in Construction Engineering along with holding multiple ICC certifications, the Author of this site has over 15 years of experience within the construction industry.
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