Allowable Building Footprint/Area vs Max Allowable SF
Can someone please explain the difference between Allowable Building Footprint and Max Allowable SF? I don't believe the calculations are difficult however whenever I encounter a question I am unsure of which direction to approach it from. For example, when to just use FAR to calculate building area/lot area  OR when to subtract setbacks from the overall lot area.. see snips from PA practice exam to reference the type of questions I am referring to .

We use FAR to get the maximum ALLOWED building area. If FAR is example 2 then we multiply the area of the parcel by 2 to get the allowed building development.
The Building footprint will now depend on the setback requirements in which case to get the maximum allowed BUILDING FOOTPRINT, we have to consider to subtract the easements and setbacks or other conditions of the zoning before we can consider to layout the max building footprint and max allowed building area of the site.

Thank you for the explanation! I guess the wording always trips me up. In the first example it asks for the maximum square footage of the building, which based on your explanation we would subtract out the setbacks however at the end of the problem we end up multiplying by the FAR of 4.
However, the second problem asks for maximum allowable square footage for the building and doesn't multiply by a FAR.
Also, the first problem calls it "building footprint area" and the second problem calls it "buildable area" which I guess are the same thing? (The site area minus setbacks)
I just wish the language was more consistent  it's probably not a difficult concept to grasp but this is just throwing me for a loop.

Are the answer and calculation wrong in the first example? FAR= Total building area/ Total parcel not buildable area. So how can you use building footprint area multiply 4 to get the total building area?? (Step 4 in the calculations). And I think this is why you get confused.
Can someone clarify if the calculations/answer is wrong in the first question?

The first question's answer doesn't look correct. It obviously misunderstood the concept of "FAR". I hope the book editor can fix those mistakes asap. (Does that mean book writers are not fully clear with what they are teaching?? how can test takers trust those study materials)
According the the wrong answer, "FAR" = Max. Allowable Building Story... Because it used "Max. Allowable Building Footprint (setbacks deduction)" x "FAR" = Max. Allowable Building Area
However, Floor area ratio (FAR) is the ratio of a building's total floor area to the size of the piece of land upon which it is built. FAR has nothing to do with the lot setback or building height.
Without consider the setback and building height limitation, the max building sqft should be Lot Area x FAR=(190'x60')x4= 45,600sqft.
From here, you can verify the Possible Max. Buildable Story= Max. Building SQFT/ Buildable Area= 45,600sf / (155'x20')=14.7=14 floor. You can possibly build 14 story building on this lot, other than only 4 story that the answer wrongfully stated.
Then looking for the lot height restriction given in the question, which is 5 story. (I think the question itself is not rigorous, it listed 15 story setback situation, but didn't mention 5 is the max. straight forwardly.) According to whatever is given here. Max Buildable Area= Max. Footprint x Story= (155'x20')x5 = 15,500sqft

Hello Esra,
Fiona's explanation is correct, FAR is the ratio of total building area to total lot area, regardless of setbacks or easements. This item was brought to our attention previously and we've flagged it for review and revision by our architect item writing volunteers to be released on a future version of the practice exam.
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