I am confused by this answer and not able to relate where is came from.
I understand parking slope should not exceed 5%?
Would 20% be a good answer on the test?
Please advise.
Thank you
This is the maximum slope allowable for a parking lot. The preferred slope for parking is 2-3%, however slopes up to 20% are permissible if conditions do not allow for gentler sloped parking areas.
Hi @ylouka ,
I think I need more information to help answer your question. Are you referencing a Black Spectacles practice exam question?
If we are talking about parking garages, per IBC section 406.4.3, vehicle ramps used for vertical circulation and parking shall not exceed a slope of 1:15 or 6.67%
Parking surfaces should be sloped for drainage. The surface should be sloped a minimum of 1% (1/8" per 1’). 2% (1/4" per 1’) is preferable and 2% is also the maximum cross-slope of an accessible path.
Anything steeper than 5% (1:20) is considered a ramp and must include handrails if it is part of an accessible path.
Thanks Coach Darion for your quick response.
Yes this is from black spectacles practice test and I really need to nail that down please because my test is tomorrow and this looks like information that might show up.
The question was asking for the maximum allowed parking slope.
And in our every day practice we usually don’t exceed 5% but in the workshop Coach Joey mentioned the maximum 6% but I can’t find this information in the IBC and I wanted to know for the ARE’s what should be the correct answer?
On the black spectacles test the correct answer was 20% and I’ve never seen this number anywhere in parking lots before.
Please advise.
Thank you
Hi @ylouka ,
I think it can depend on the specifics. 5% is typically a good rule of thumb maximum for a parking lot as 5% (1:20) is the maximum slope for an accessible route that is not considered a ramp requiring a handrail per ADA & IIC 117.1 .
Per the IBC section 406.3 shown in my previous response, if you’re designing a parking garage with ramp that will also be used for parking the max is 1:15 or 6.67% - I think this was likely the 6% Joey was mentioning.
@coachchrishopstock can you please look into the 20% on the Black Spectacles question and see if you can help explain?
I’ve heard 20% thrown around colloquially as the max for a vehicular ramp, not used for parking, but my understanding is that the max vehicular slope can vary based on municipality.
Thanks,
-Darion
These are the exact words for the question and answer:
Ignore accessibility requirements, what is the maximum longitudinal slope for a parking lot?
20%
Correct. This is the maximum slope allowable for a parking lot. The preferred slope for parking is 2-3%, however slopes up to 20% are permissible if conditions do not allow for gentler sloped parking areas.
Thank you
Hi @ylouka - this information is found in the site planning and design handbook, second edition, on table 7.4. We have that information listed as the reference for the question - I’d always suggest checking out the reference if a topic is confusing!
I agree that 20% seems a bit steep for parking, but the question is asking about the maximum allowable slope (not the best-practice slope) and the answer (20%) is clearly listed in one of the ARE 5.0 reference materials.
One of the BS practice questions also rules out a 12% slope at parking in this question:
An architect is reviewing the preliminary designs for a new school building. The following answer choices describe the design concepts as presented by the design team for the project.
What preliminary concept should be revised?
A. All existing drainage patterns on the site should be maintained as much as possible and not changed.
B. The west side of the lot has a 12% slope and is well suited for a surface parking lot for students and staff.
C. The athletic fields should be located on the east side of the site where the existing grade is a 1-2% slope.
D. The school building should be placed on the north side of the site where the existing grade is a moderately steep slope.
Answer: (Click blurred text to reveal)
[spoiler]The answer is B. The west side of the lot has a 12% slope and is well suited for a surface parking lot for students and staff.
12% is too steep for a parking lot.
Ref: Building Construction Illustrated[/spoiler]
I answered D for this question as i remember 20% being max when not considering ADA.
Great Point! So according to ARE and Architectural practice if references have directly contradicting requirements architect should follow the most stringent one. Since ARE Handbook lists as a reference Site Planning and Design as well as International Building Code 2018 they are equally valid references. While Site Planning and Design states in Table 3.4 Typical Grading Standards that Parking lots maximum grading is 20%
While IBC prescribes the slope for parking structures, not sites. The logic suggests that the slope on the site, exposed to the elements, won’t be steeper than the one inside of the structure.
