I have a new construction build where there is a basement entry in the garage. They have a curb around the one side but not at the front of the stairs. I remember my mentor telling me years ago that was incorrect but I don’t see any codes referencing this. I would imagine the curb would be more dangerous than the possibility of vapor migration. Anyone have any reference source for this? There is a fire-rated door at the bottom landing to the basement.
Curb at the top of the staircase is a huge hazard.
Fire door also solves the vapors issue.
Should be a floor drain at the bottom of the staircase.
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Is there a slope in the garage floor down and away from the stair set?
Floor drains are there own set of problems though. People will pour anything down there.
Yes, there is a moderate slope away from the stairs.
as Jeffery said a curb at the top of the stairs would be a serious trip hazard…
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They have that curb on the long opening side to prevent cars from falling into the stairway hole.
The stairway width is 36 inches minimum, but maybe slightly wider if you paid extra? Your average car isn’t that narrow, so it can’t really fall in through the front.
Other than that, it’s not that much different from an interior stair.
I also don’t like how they did the railings. You have a short piece of concrete, then a short railing, easy for kids to climb over.
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Then I would not be concerned about not having a curb there. Hopefully the driveway slopes at least a little down and away or the pad is lower than the garage door lip? That will help prevent back-up toward that stair set.
The side curb is not only to prevent vehicle accidents but also people accidents and water flow over the edge if it occurred close to the stairwell.
Within the codes the following sections would be reviewed.
R311 Means of Egress - Nothing here would cover that. However do take note that egress must be available from all locations in the home and must not pass through a garage. Hopefully there is another egress point from the basement.
R309.1 Garages and Carports - Here you will find the floor slope to overhead door requirement but nothing else unless it is in a flood hazard area.
With the Codes that would be it so it now falls on the engineered plan for the home and if this was called for and approved by the AHJ.
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I would suggest painting a 6” wide yellow stripe on the concrete at that top step just to bring attention to the drop down at the step.
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Thanks for the responses. I didn’t think there was any code associated with it, I just wanted to check in here. I didn’t call it out but I did talk to the client about it.
There should be a 4 inch curb at the top of the stair to prevent gasoline vapors from traveling down the stairs and into the basement. This should be accomplished with a a step up to a platform before reaching the main stair in order to prevent a fall down the stair. The wood guardrail shown in the pic is too low. Needs to be 36" high with openings not to exceed 4 inches.
Where is the code showing the 4" step up at the stairs?
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It may be a Local Code, but I doubt it. Too stoopid of a requirement, even for local AHJ’s!
The Firedoor at the bottom of the staircase will typically address the concern(s)!
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Prior versions of the Codes (including BOCA) might have required a curb if the garage floor was not properly sloped downward toward the garage overhead door. This was mostly to address the prevention of water and potential vapors from entering the conditioned space of the home. Even though most new home garages are sloped we here in Texas still see the use of a short curb (typically 2" high) at the back of the garage where the wall is abutting the conditioned space. This now is really only to help protect against water flows into the home since many have their water heaters (tank and tankless) as well as water treatment systems located in the garage. Also it is permissible to run a tanked water heater overflow pan to the garage floor if it is properly sloped and curbed.
That would not stop local AHJ’s from having amendments to the Codes requiring a curb.
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IMO the whole 4” curb thing doesn’t make sense. Think about water heaters before FVIR. They were required to be elevated 18” off of the garage floor to get the pilot, burner, element, contactor, or other source of ignition from igniting potential gasoline vapors in the garage. Soooo if gasoline vapors can reach as high as 18 inches…what does 4 inches of wood do?
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In the 2009 IRC and later editions, this specific 4‑inch curb requirement was removed. The code rationale was that garage slabs must slope toward the overhead door, and vapors would follow that slope; therefore, the curb was considered unnecessary in most cases.
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That’s what I found in my research as well.