Picture an Old Tappan lot that falls away toward the back. From the street, the house on it is two stories with a peaked roof. From the backyard you see three levels of windows, because the lowest floor opens straight onto the lawn. Under the borough's zoning code, that bottom level is often not a story at all, and none of its square footage counts toward the house's size limit.
That one definition carries more weight than most buyers expect when they size up an older Old Tappan home for an addition or a rebuild. It is also a definition the borough's newly adopted master plan says future rules could refine.
The basement rule that sets the size of a rebuild
Old Tappan's zoning chapter, Chapter 255, defines a basement as space that sits partly below average finished grade, with no more than 50% of it below grade and no more than six feet of it above. Space more than half below grade is a cellar, and the code says a cellar "shall have no bedrooms." The same section defines a story so that basements, cellars and crawl spaces don't count, and a space averaging under seven feet in height counts as a half-story.
Floor area works the same way. The code's floor-area definition leaves basements, cellars, decks, patios and attics out of the floor area ratio calculation. It also leaves out garages at or below basement level, up to two-car capacity and 400 square feet. According to the borough's residential area and bulk schedule, the height cap for one-family districts is 2½ stories and 35 feet to the ridge line.
Put those rules together and the size of a house depends heavily on what happens below the first floor. On a sloped lot, a walk-out level can work like a full floor of living space while counting toward neither the story limit nor the FAR.
The table below uses the FAR and coverage figures from that bulk schedule and the caps from the oversize-lot FAR table. It shows what the FAR allows above the basement line today, figured at each zone's minimum lot size.
| Zone | Base FAR | Floor area at minimum lot | Cap on oversize lots | Building / improved-lot coverage |
|---|---|---|---|---|
| RA-10 | .28 | About 2,800 sq ft on 10,000 sq ft | 5,000 sq ft above 20,000 sq ft | 30% / 55% |
| RA-15 | .26 | About 3,900 sq ft on 15,000 sq ft | 6,300 sq ft above 30,000 sq ft | 25% / 50% |
| RA-25 | .22 | About 5,500 sq ft on 25,000 sq ft | 7,500 sq ft above 50,000 sq ft | 20% / 40% |
| RA-40 | .16 | About 6,400 sq ft on 40,000 sq ft | 8,400 sq ft above 80,000 sq ft | 15% / 30% |
On bigger lots, the ratio gets smaller as the lot grows. In RA-10, the oversize-lot table drops the ratio from .28 to .25 by the time a lot reaches 17,500 to 20,000 square feet, and above 20,000 square feet the limit becomes a flat 5,000 square feet. Those table footnotes cite amendments dated February and November 2005.
What the plan says it wants to change
The Old Tappan Planning Board adopted the 2026 Master Plan Reexamination Report and Master Plan Land Use Plan Amendment on August 12, 2026. It was prepared by the borough's planning consultant, Burgis Associates. The report keeps the goals of the 2006 plan and makes targeted amendments. One of them describes the trend it is responding to:
"Old Tappan recognizes that infill development characterized by the demolition of older and smaller homes in favor of larger residential structures has been an ongoing land use trend within the past decade."
The report says it wants to encourage investment that modernizes the housing stock, as long as that investment is sensitive to the character of existing neighborhoods. It then names the tools future rules "could consider":
- Modified setbacks for upper floors
- A maximum upper-floor area in relation to lot size
- Height and scale limits tied to established grade
- A refined definition of "story" as it relates to walk-out basements and their relationship to the immediate surroundings
The last item goes straight at the gap described above. The same amended objective stresses "the benefits of rehabilitating homes instead of removing them." The report also tells the borough to keep watching its "twice revised" FAR provisions, calling that kind of ordinance "a work in progress." It recommends revisiting the limits on how many accessory buildings a lot may have and how big they can be, garages included.
The report does not set a new house-size cap and it does not ban teardowns. It lists options that future ordinances could use, and none of those ordinances has been written yet.
How quickly the plan is turning into ordinances
On September 21, the Mayor and Council voted to have borough professionals draft ordinances that put the plan's recommendations into effect. Two weeks later, on October 5, the first one was introduced. Ordinance 1307-26 amends Chapter 255 to regulate boardinghouses and short-term rentals. It was adopted on final reading October 19 and, according to the borough's notice, is "now in full force and effect." The master plan had recommended generally prohibiting short-term rentals in residential districts.
The October 19 Council agenda listed 1307-26 for hearing and adoption and included no ordinance on house size, FAR, stories or accessory structures. The online code also lags behind. Old Tappan's posted code on eCode360 includes legislation only through June 1, 2026, so it does not yet show 1307-26. For the next few months, the official code is likely to trail what Council has actually adopted.
So the borough moved from authorization to an adopted ordinance on one recommendation in about four weeks. The house-size options are still on the plan's list, with the possible tools already named.
Who this changes the math for
A buyer looking at an older, smaller house on a generous Old Tappan lot is often paying for two things: the house that stands there now, and the house the zoning would let them build in its place. Today's version of that second number depends on the FAR schedule above plus a basement definition that the plan lists as a candidate for future refinement. For the seller of that same house, the land's appeal to a rebuilder rests on the same rules.
The plan itself points out the tension. It says Old Tappan "has a very small inventory of smaller homes that are available as starter houses," and that smaller homes on smaller lots give empty nesters a manageable place to downsize. It recommends that the borough look into that shortage. Every teardown of an older, smaller home removes one of those houses, and the plan pairs its size-limit options with an emphasis on rehabilitation.
Countywide, the market leaves little time to sort this out once a contract is signed. Bergen County single-family homes that sold in September 2026 spent a median of 34 days on market and closed at 103.4% of list price, according to NJ REALTORS® data current as of October 9, 2026. Those are county figures, not Old Tappan-only figures. In a market moving that fast, questions about zoning and buildable area are easier to settle before an offer than during attorney review.
The other half of the plan is at Bi-State Plaza
The plan's Goal 8 says commercial development "will only be encouraged within existing commercial areas" and that expansion into residential areas will not be. The land use amendment maps an existing Town Center Overlay covering 18 parcels and 34.5 acres. That includes a 21.9-acre mixed-use area over Bi-State Plaza and the B-1 frontage, plus a 12.6-acre professional-office area along Old Tappan Road west of Central Avenue and at Old Tappan and DeWolf Roads.
The plan describes a grocery-anchored, mixed-use center with village-style pedestrian streets, gathering areas and a "Green Mobility Spine" in place of the central parking field. Its design list includes outdoor dining, a civic green or event lawn, shaded seating and EV-charging courts. The report cites the former Pearson Education campus at 200 Old Tappan Road, rezoned in 2019 for mixed housing next to Bi-State Plaza, as a precedent for the corridor. Park & Arbor, a 130-unit apartment complex, opened on that site in 2024, as NorthJersey.com reported.
A few direct questions
Does the master plan change what can be built on my lot today? A master plan guides future ordinances. The bulk rules codified in Chapter 255 are the current zoning text, and the October 19 Council agenda included no house-size amendment.
What limits apply to a detached garage or shed now? Under §255-54, an accessory garage is limited to 14 feet high and 400 square feet. A lot generally gets one accessory building, plus a second structure of no more than 150 square feet, which may only be a shed. The master plan recommends revisiting these limits.
Where can I read the plan myself? The adopted report is posted on the borough's Planning Board master plan page.
This post is general information, not legal advice. If you're planning a purchase, addition or rebuild, confirm the rules for your specific lot with a land use attorney, architect or the borough's zoning office.
If you own an older Old Tappan home and want to know how much of its value comes from the house and how much from what the lot allows, Sara Deutsch and Kevin can run that analysis for you under today's rules and keep you posted as the borough drafts the next ordinances. Get your home value to start that conversation.
