Navigating the Landmarks Preservation Commission

Adding Modern Extensions to Historic Brownstones

Most of our projects require the approval of the NYC Landmarks Preservation Commission (LPC). With over a hundred Landmarks approvals under our belt, we’ve learned what works and what doesn’t. Here’s everything you need to know about adding contemporary additions to historic homes in NYC’s landmarked districts.

Say you’ve fallen in love with a classic New York brownstone, but you want to maximize the value of the property or add space for your growing family. The good news? Adding modern extensions to buildings is our bread and butter. The challenge? Navigating the additional approvals.

The Mission of the Landmarks Preservation Commission

After the destruction of the original Penn Station in 1963, New York City established the Landmarks Preservation Commission, empowering it to protect the city’s architectural heritage by regulating changes to historic buildings. These include any structure within a historic district: e.g., Soho and Greenwich Village in Manhattan, or Brooklyn Heights and Fort Greene in Brooklyn. (Look for the telltale brown street signs.) But historic buildings can also be individual landmarks outside of historic districts: from world-famous Grand Central Station to the little-known but lovely McKim, Mead, & White building at 108 Leonard Street.

Types of Landmarks Preservation Commission Approval

The LPC grants three main types of permits—Certificates of No Effect, Permits for Minor Work, and Certificates of Appropriateness—based on the project’s impact on protected features. These range from expedited staff-level approvals for minor, non-visible work to extensive public hearings for major alterations.

Certificate of No Effect: Issued when the proposed work (often interior, requiring a Department of Buildings permit) does not affect the protected exterior architectural features of a landmark. LPC staff is often backlogged, so expect a 60-day wait.
Permit for Minor Work: Required for smaller exterior alterations that do not require a Department of Buildings (DOB) permit but still affect the building’s character, such as replacing windows or doors in-kind.
Certificate of Appropriateness: Required for major alterations, such as additions, demolitions, or significant facade changes. This process involves a public hearing, which adds at least 90 days.

To the original three, LPC has recently added two accelerated options for approval:

FasTrack: a 10-day application process for both interior and exterior alterations, so long as the latter is at non-visible facades and roofs.
Expedited Certificate of No Effect: XCNE is an even faster approval–just 5 days for specific, minor interior alterations. An XCNE can be used for interior work that affects no landmarked feature, that’s above the second floor or below the ground floor, and that includes no underpinning.

So what requires LPC approval? For landmarked properties, the short answer is everything. You may think the LPC couldn’t possibly care if you redo your powder room, but the LPC wants to be the one to decide that. And as far as the DOB is concerned, if the property requires LPC approval, your changes do, too.

Required Steps for Landmarks Preservation Commission Approval

Step 1: Preliminary Research

To determine if your property is an individual landmark or within a historic district, you can check this NYC Landmarks map. To confirm whether the DOB also considers the property landmarked, consult the Buildings Information Search page. If the Landmark Status field has an “L,” it requires LPC approval. FYI, a “C” stands for “calendared”, meaning the site is under review for landmark status. Calendared properties must go through the LPC process until the city makes a final decision on the district’s designation.

Step 2: Develop Your Design

Work with an architect experienced in LPC approvals to create drawings that meet both your needs and preservation guidelines. This is an iterative process that studies the building in plan, section, elevation, and 3D. Developing a design typically takes two months before it’s ready for LPC submission.

Step 3: Submit Your Application

Your architect will prepare and submit the LPC application, including architectural drawings, historic tax photos, and a written description explaining how the design meets LPC criteria. The drawings will include plans, elevations, details, and renderings showing how the addition relates to the historic building and surrounding context.

Step 4: Staff Review

For straightforward projects, LPC staff may issue a Certificate of No Effect or approve the work at the staff level. More complex projects go to the full Commission. Both typically require multiple requests for modifications and additional information from your architect. LPC will insist that you’ve cleared all DOB zoning objections before graduating you from this step.

Step 5: Public Hearing (if required)

Major alterations require a public hearing before the full commission. Prior to this, however, your architect must schedule and present your project to the governing Community Board and to any neighborhood organization (e.g., the Brooklyn Heights Association). Tellingly, the LPC doesn’t require approval from these organizations, just their vote. Once they’ve voted, the LPC schedules your architect’s presentation at the public hearing. The first half is your architect’s slide show, and in the second half, the commissioners will ask questions and provide feedback. Organization representatives are also invited to present their arguments for or against the project, which are summarily ignored. The commission will deliver its verdict at the end of the hearing.

Step 6: Approval and Permits

Once the commission accepts your proposal, it often takes the LPC staff several weeks to formally grant its approval. Note–the approval will arrive as a cryptic email: “This email is to notify you that a FINAL ACTION has been taken on this application, and associated documents are being prepared by LPC. These documents will be found in your Completed and Issued tab on your Portico dashboard.” Believe it or not, that’s what you’ve been waiting for! And with that approval in hand, you can proceed with DOB applications and permits.

Bonus Tips for Winning Approval

Successful LPC-approved projects share common characteristics:


	Visibility Matters
	The LPC is most concerned with what’s visible from the street. Rear-yard extensions and rooftop additions that aren’t visible from public thoroughfares have an easier approval path than changes to the front facade. Be sure to circle around the block to see if your addition is visible through any gaps. Beyond that, the top of a rear wall will get more LPC scrutiny than the bottom, because it’s visible to more of your neighbors.
	Context is Key
	Analyze the neighboring buildings to judge whether your changes will be accepted. If your house is part of an intact row of Romanesque Revival rowhouses, LPC will be stricter than on a block of diverse structures. Likewise, if the rear facades of your neighbors are a repeating pattern, LPC will want that pattern maintained. Note cornice heights, window alignments, and deviations in massing anywhere in the donut.
	Preservation First
	Landmarks’ mandate and top priority is preservation. Before altering a building, demonstrate your commitment to preserving existing historic features. Repairing original windows, restoring masonry, and maintaining architectural details builds goodwill with the LPC.
	Respectful Contrast
	Novices often assume the LPC wants imitations of historic details. Not true. If preservation is unfeasible, they will allow you to match a historic feature, typically adhering to specific recipes. But they are surprisingly open to insertions that are clearly modern and contrast with the original architecture. Think large windows, sleek metal frames, and simple geometric forms. In these cases, clarity is their goal, both to distinguish the original from the new, and for the sake of reversibility. In other words, if a future owner wanted to restore the building to its original condition, the LPC wants to ensure they can.
	The Devil is in the Details
	LPC staff is especially ardent about certain details. For example, brickmold—the little strip of wood trim that covers the gap around exterior doors and windows—is critical. New brickmold must match the original profile. This is easy to demonstrate if any original windows still have their brickmold. Alternatively, a neighboring building may have some original brickmold. In a pinch, you may be able to identify the brickmold profile in the depression-era tax photos the city keeps of each property in its municipal archives.
	Quality Materials
	Using high-quality, durable materials shows respect for the building’s longevity. We’re big supporters of materials that have withstood the test of time: bluestone pavers, architectural glass, copper flashing, solid brick and mortar. LPC allows clad windows at the rear façade but insists on wood windows at the front façade.
	Don’t Forget Color
	Black and white photography might lead you to believe paint colors were invented in the 20th century. But historic architectural features were often brightly colored. LPC will insist you scrape away at paint layers to find and match the original color.

Ready to Start Your Project?

Adding a modern extension to your historic Brooklyn home doesn’t have to be daunting. With the right design approach and experienced guidance, you can create beautiful new spaces that enhances both your home and the neighborhood.

Have questions about your specific property? We offer free initial consultations to discuss your project’s feasibility, timeline, and budget. Contact us to explore how we can help bring your vision to life while honoring Brooklyn’s architectural heritage.

With over 30 years of experience in the field, Sherman Architects is the city’s leading expert at successfully guiding projects through LPC review. The firm specializes in sustainable, modern additions to residential architecture throughout Brooklyn and Manhattan, with particular expertise in historic preservation and Landmarks Preservation Commission approvals.