FAR numbers? Confused.
Hi, I am trying to determine whether I can build a small room on our roof and looking at the OASIS map I pulled up the following: Lot Area: 1,917 sq ft (19′ x 100.92′) # of Buildings: 1 # of floors: 4 Building Area: 12,168 sq ft Total Units: 3 Residential Units: 3 Primary…
Hi,
I am trying to determine whether I can build a small room on our roof and looking at the OASIS map I pulled up the following:
Lot Area: 1,917 sq ft (19′ x 100.92′)
# of Buildings: 1
# of floors: 4
Building Area: 12,168 sq ft
Total Units: 3 Residential Units: 3
Primary zoning: R7-2 Commercial Overlay: None
Floor Area Ratio: 6.35 Max. FAR: 3.44
Can somebody who has a bit of experience with this sort of thing explain what the numbers above mean and whether there is enough FAR for a small room? Much appreciated.
Thanks.
Thanks all for the input! I am getting somebody in to measure the roof, so hopefully that will help figure out how much FAR is left to play with.
HDL, as far as maximum height goes, any idea where I can find that info?
I checked a couple of other buildings nearby and they all seem to have similar FAR numbers as our neighbors. This building recently built a room on their roof:
Lot Area: 1,817 sq ft
# of Buildings: 1
# of floors: 4
Building Area: 3,960 sq ft
Total Units: 14 Residential Units: 14
Primary zoning: R7-2 Commercial Overlay: None
Floor Area Ratio: 2.18 Max. FAR: 3.44
JimHill, I will certainly avoid OASIS for now and have the place measured properly.
For now, your best bet would be to stop looking at oasis. The site is very helpful at gathering resources together, but it not something to rely upon for existing conditions. As you can see, your property report is vastly different than your neighbor’s with the same exact building. Chances are, the neighbor’s is closer to correct, but even then it’s probably not exactly right.
The only way to get a real, accurate determination of the existing FAR is to have a survey done of the existing property. You can do it yourself or you can hire an architect or land surveying engineer to do it.
To do it yourself, just measure from the front of the building to the back. If measuring from the inside, add a foot or so for the front wall and another for the rear, don’t forget to include interior wall thicknesses.
This will give you the overall length of the building, but without an engineer’s survey you won’t know about yards. To apply for a building permit for the extension, you’ll need the engineer’s survey, so it may be a good idea to get one anyway.
So, either way, determine the building depth, then contact an architect to determine the exact existing FAR.
You will never win at this game as a novice. Talk to an expediter. They know better than the city. You may find out that FAR is fine but the roof room needs several feet of clearance on either side.
Also as part of construction you will need to bring the whole building up to the latest fire and building codes so make sure you are ready and able to spend 200K for that room.
How big is your rear yard?
From what I see 12,168 is the ALLOWABLE sq. ft at FAR 6.35 or 6595 at 3.44. Which is it?
But lets say the building has a code compliant minimum rear yard of 30′ for light and air that would yeild a floorplate of 19ft x 71ft or 1349 sq.ft. which comes to 5396 sq. ft. overall at 4 stories. That’s certainly less than the 12168 and also 1198 sq.ft. less than 6595.
Based on this very sketchy estimate you sould have no issue building a 1198 sq. ft. room.
If your rear yard is bigger since rarely are bronstones 71 feet deep (I suspect it is or maybe there’s a front yard), then that square footage becomes available on top.
Lastly, you may want to check if there’s a specified maximum height as Carroll Gardens recently imposed a 50 foot limit on buildings.
Strange guys isn’t it. The building area size is insanely high also: 12,168 sq ft. Our neighbor, with an identical brownstone has a building area size of 3,952 sq ft. Plus, their FAR numbers are:
Floor Area Ratio: 2.06 Max. FAR: 3.44
Weird thing is, both buildings are identical, same height etc.
We are certainly a 4 floor building, but how do I determine how much of the lot each floor occupies? Am I correct in thinking the lot includes the garden? In that case, would each floor cover 50% of the lot?
Thanks.
It’s not possible to have a 4 story building with an FAR of 6.35. If each floor covered 100% of the lot, you’d have an FAR of 4.00.
To visualize it, an FAR of 3.44 would be a building w/ 3 stories covering 100% of the lot, and a 4th story covering 44% of it. If your building is around that size or bigger, then you probably can’t add on (although there are small exclusions/bonuses that may mean that some floor area is not counted towards the FAR).
If your building is smaller than that, you’re probably ok in adding a small room…assuming you don’t run into height/setback restriction issues.
Hi Jim,
Thanks for the info. It is definitely a bit strange. Our neighbor who has exactly the same building (brownstone), size etc. has the following info:
Lot Area: 1,917 sq ft (19′ x 100.92′)
# of Buildings: 1
# of floors: 4
Building Area: 3,952 sq ft
Total Units: 3 Residential Units: 3
Primary zoning: R7-2 Commercial Overlay: None
Floor Area Ratio: 2.06 Max. FAR: 3.44
A couple of things that stand out – our building area is listed at 12,168 sq ft and his is 3,952 sq ft. I don’t even know how that makes sense since they are identical (stoop, yard etc.).
Also, the buildings are exactly the same height, yet his Floor Area Ratio is: 2.06.
Any idea what is going on here and could it be a problem if I have plans filed to build a room? Also, we have 3 years left of a property tax abatement, will we get hit hard because of this 12,168 sq ft designation?
Thanks!
Oasis FAR’s are often off because they make some assumption in the calculations that may or may not be correct. However, the numbers you’re listing are huge. An actual FAR of 6.35 in a district that allows 3.44. Either this building has some serious bonuses, has bought air rights from neighbors, or was built prior to the current zoning. Either that or Oasis is way off on this one.
Short story, if this is correct, then the building is way over allowable FAR and there’s no room for more.