Townhouse Additions NYC Landmarks

by | Last updated Nov 26, 2021 | Additions / Enlargements, Landmarks, Townhouses

New York City has very strict Zoning and Building Codes as well as regulations on Landmark Buildings. Depending on the specific zoning district regulations on a given property it may be possible to enlarge a townhouse by building an addition to the existing structure. There are certainly many codes that will apply and this becomes even more complicated when we are talking about a landmark townhouse. The good news is that in many cases you can build an addition to a landmark townhouse in NYC.

Building an addition to a Historic Landmark Townhouse will require approval from the NYC Landmarks Preservation Commission (LPC) and a permit from the NYC Department of Buildings (DOB). This type of application will undergo Zoning, Building Code, and Landmark Preservation review in order to be approved.

I am Jorge Fontan an architect in New York and owner of Fontan Architecture. As I write this post my office is currently working an a vertical enlargement on a Landmark Brownstone in Manhattan where we are adding a floor on top of an existing Townhouse. I am going to use this as an example and cover some of the general concepts in regards to building additions to a landmark Townhouse in NYC.



The first step to planning an addition in NYC is for an architect to perform a Zoning Analysis in order to determine if the proposed enlargement is feasible. New York City has very strict zoning regulations that will dictate the size of the building as for square footage which is based on the Floor Area Ratio or FAR of the building. There are other bulk and use regulations such as building height limitations, setbacks, yard requirements, number of dwelling units, and various other zoning matters.


Planning an Addition to a Landmark Townhouse

If you want to build an addition to your townhouse you are have two basic options building up or building back. Of course you can consider doing both if you have the ability to do so within your zoning regulations and budget.


Landmarks Preservation Commission Filing

Building an addition to a Historic Landmark building or within a Landmark district will require approval from the NYC Landmarks Preservation Commission (LPC). You will also need a permit from the NYC Department of Buildings (DOB) to build any form of addition. These types of applications with LPC have two types of reviews that you may face: Staff level or Full Commission review and Public Hearing.

A staff level review is preferable option when dealing with LPC, as it will most likely be an easier and faster review process. There are going to be architectural requirements for additions that will dictate what review type will apply. For Example line of site and visibility of the addition will need to be established. The overall height of the addition is another matter to take into consideration. If the addition falls within the acceptable limitations it can be reviewed by LPC staff. This is a preferable option as it will take some time but will not be as extensive as Public Hearing.

If the addition exceeds the height limitations for a staff level review, the LPC will require a full review by the Commission with a Public Hearing. This will most certainly take longer and be a much more involved process. The biggest problem is that they could possibly deny your application, but of course there may be ways to work with them through compromise on the design to achieve your goals. By this point, you will have spent a great deal of time, energy, and money just to receive a potential denial, so be prepared that you may need to rethink the design based on objections raised during the review.


Building a Mock Up

In order to build the addition LPC will most likely require you to build a mockup. A building addition mockup is a temporary structure built to demonstrate the overall size and shape of the addition. The purpose will be to see how visible the addition is from the street and the magnitude of it’s impact on the architectural character of the townhouse and block where it resides.

The mock up can be pretty simple usually built of 2x4s and orange mesh. The General Contractor will assemble this under the direction an architect, such as myself, and it must accurately represent the proposed extents of the addition design. As the architect for the addition I must verify it’s accuracy, document it with sufficient photographs, and invite the LPC staff to come to the jobsite and view the mockup themselves.


Historic Records

As with any Landmarks project the process should begin with Historic Records. As the architect I need to determine if the building is an individual landmark or within a historic district. We will identify the building style, original architect, construction date, find historic photos, document the existing conditions, etc..


Rooftop Additions

A vertical enlargement to a Landmark Townhouse will be reviewed for appropriateness of size, visibility, architectural form, materials, color, architectural features. The bottom line is that the LPC does not want you to ruin the existing character of the building or neighborhood. You should always have respect to the original architecture for two reasons. First it will make things easier with LPC. The second is that you will probably have a greater architectural character within the final product if you respect the original design.

Rooftop additions of any significant size will be subject to a public hearing and commission review, if it is only one story and falls within the LPC guidelines it can be reviewed at staff level. This will be ideal if you are hoping to move the project along and not get caught up in what we affectionately refer to as “Landmarks Hell”.


Rear Yard Additions

When proposing a rear yard addition to a landmark structure we need to analyze the block and identify what other properties have existing additions that are not original to the building. This analysis must include the height and depth of the existing additions.

If the rear yard addition is not visible from the street at any point this will be a great advantage to the review process. If the enlargement will be visible from the street you will incur greater scrutiny.


Landmark Townhouse Additions

It is possible to build an addition to a Landmark Townhouse in NYC but this is an involved and complicated process. Logistics and execution of design / architectural character, and many other factors will impact weather or not this proposal will be successful. I greatly recommend embarking on the project with an open mind and willingness to compromise. As in any other project game planning in advance and proper preparation will often be the determining factor for success.


Thank You for Reading Our Blog Post on Building Additions to NYC Landmark Townhouses. 

I hope this was helpful. If you would like to speak with an architect about a potential project you can contact us at Fontan Architecture directly.


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Jorge Fontan
Jorge Fontan

This post was written by Jorge Fontan AIA a Registered Architect and owner of New York City architecture firm Fontan Architecture. Jorge Fontan has earned 3 degrees in the study of architecture including two degrees from the City University of New York and a Masters Degree in Advanced Architectural Design from Columbia University. Jorge has a background in construction and has been practicing architecture for 15 years where he has designed renovations and new developments of various building types.