Saturday, January 28, 2006

Real FAR













At the public meeting on Thursday, we discussed this Floor Area Ratio (FAR) thing again. The FAR is the ratio of built area to site area. It’s important because it’s the accepted measure of building density on a site in the city. While open space, building setbacks, and height limitations constrain building configurations, FAR is the way we understand how much building can be on the site. And depending on the use of the building (residential, commercial, etc.), FAR also becomes a pretty good indication of the number of people that will be there, and their impact on traffic, services, utilities, and so on.

The public assembly use of the arena makes its impact not really measurable by an FAR, since the impact of crowds is out of proportion to the typical use of built areas. However, because the proposed project includes an arena on the site, the air rights for density will be transferred to the rest of the site, making the non-arena components much denser than they would be without the arena. This in itself is a reason to limit the averaged FAR on the site, as a whole, to something reasonable, since the non-arena areas will be much denser than the average.

What is an appropriate FAR for the site? We’ve discussed in previous posts that the ratio of built area to site area is relative to the pattern of streets and blocks. An FAR figure for a superblock is not comparable to an FAR for a typical Brooklyn block, because a superblock uses the street for part of the site area. The chart below compares the two blocks at the eastern end of the site - each nominally 200’ x 1000’, on either side of a 70’ (property line to property line) street - with a superblock occupying the same total area. Dimensions would need to be verified for the entire site to make a definitive comparison.


Built Area (sf) ....Superblock FAR ......Brooklyn-block FAR
470,000 ................1.00 ........................1.17
940,000 ................2.00 ........................2.35
1,410,000 .............3.00 .........................3.52
1,880,000 .............4.00 ........................4.70
2,350,000 .............5.00 ........................5.87
2,820,000 .............6.00 ........................7.05


So when we hear that the proposed FAR on the site with demapped streets will be say, 6.00, we will understand that to be equivalent to a Brooklyn-block 7.05, which is significantly more dense. And conversely, if we can understand a density equivalent to an existing-street-pattern FAR of 6, we should be looking for a superblock calculation of about 5. We’re not developers, it’s not a position to negotiate from, nor will we be asked to negotiate this position, it’s just the facts. The Extell proposal proves that a 6.0 FAR with streets retained is economically feasible.

Why a real 6.0? This is substantially more dense than current zoning. The current Zoning Map shows three different zones on the site: R6B (FAR = 2.0), for the North side of Dean between 5th and Carlton (and most of Prospect Heights), R7A (FAR = 4.0) for the Flatbush and Vanderbilt corridors, and M1-1 (FAR = 1.0) for the remainder of the site. But downtown Brooklyn has recently been rezoned much denser, with some limited areas at 10 and even 12 FAR, surrounded by 6.02 FAR areas.

For the Atlantic Yards site, 6.02 appears to be the intent of the Downtown Brooklyn Development Plan. On their web site, City Planning explains the Downtown Plan: “Rezone Southern Flatbush Avenue Area to C6-2…Increasing the residential FAR from 3.44 to 6.02 would encourage new residential development….and support development surrounding Atlantic Terminal”. While the Atlantic Yards site is not in Downtown Brooklyn, the Downtown Brooklyn Development Plan was developed with an understanding of the surrounding neighborhoods. The Downtown Brooklyn Development Plan went through the ULURP process, was recommended for approval by the Borough President and Community Board 2, was approved by the City Planning Commmission, and was adopted by City Council on June 28, 2004 (with a modification establishing building height limits). We have to believe these people did their homework.

1 Comments:

Anonymous Norman Oder said...

You wrote:
"For the Atlantic Yards site, 6.02 appears to be the intent of the Downtown Brooklyn Development Plan."

I think that only applies to the NW tip of the AY footprint. Otherwise the Downtown Brooklyn plan is silent.

9:44 AM  

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