Pre-war apartments are some of the most charming homes in New York City. High ceilings, plaster moldings, solid wood doors, real foyer space — these details are a big part of why people choose a pre-war co-op or condo over new construction.

But that character comes with a trade-off: behind the walls, many pre-war buildings were never designed for modern kitchens, spa bathrooms, or central air. Renovating one of these apartments in Manhattan or Brooklyn can be incredibly rewarding, but it’s rarely simple.

Here’s what you need to know before you start a pre-war renovation in NYC.

1. Expect “Hidden” Conditions Behind the Walls

Most pre-war apartments still have original or partially updated systems. Once demolition starts, it’s common to discover:

• Lath and plaster walls instead of modern drywall
• Old wiring with limited capacity and no grounding
• Aging plumbing with corroded pipes or poor past repairs
• Uneven floors and out-of-square walls

These conditions aren’t necessarily a dealbreaker, but they do affect the scope and cost of your renovation. A “simple kitchen update” in a pre-war building often becomes:

• New wiring to support modern appliances and lighting
• Reframing or leveling walls and floors
• Replacing or re-routing old plumbing lines
• Additional plaster work to repair cracking or patching

The key is to build a realistic contingency into your budget and timeline for pre-war surprises, because there will almost always be some.

2. Electrical Upgrades Are Almost Always Part of the Plan

Most pre-war apartments were wired long before dishwashers, induction ranges, multiple TVs, and home offices were standard. Today’s electrical demands usually require upgrades.

Common electrical changes in pre-war renovations:

• New electrical panel with higher amperage
• Additional circuits for kitchen appliances and AC
• More outlets in living spaces, bedrooms, and work areas
• Compliance with current code (e.g., GFCI and AFCI protection)

Sometimes the building will require upgrades not just inside your apartment, but also to the way your unit ties into the building system. This can add cost and coordination with management and the building’s electrician.

A good contractor like DNB Renovations, who regularly work in pre-war buildings can help you plan these upgrades so you’re not tripping breakers the moment you plug in a hair dryer and a space heater.

3. Plumbing Work Needs Coordination (and Often Approval)

Pre-war plumbing stacks can be sensitive, and boards are protective of them for good reason. When you renovate:

• Moving plumbing fixtures (like shifting a toilet or shower) may be tightly regulated—or not allowed at all.
• Tying into old risers may require building-approved plumbers and specific materials.
• Stack shut-downs for work can only happen at certain times and must be coordinated with other units.

You may also be required to upgrade:

• Old shut-off valves
• Venting for fixtures
• Waterproofing under tile, especially in bathrooms and kitchens

In some buildings, even if you only refresh finishes, you’ll still have to bring certain aspects of the plumbing up to current code once the walls are open. This is where experience with pre-war co-ops and condos becomes invaluable.

4. Noise, Soundproofing, and Floors Matter More in Old Buildings

With thinner floor assemblies, original subfloors, and neighbors above and below, sound can be a major issue in pre-war buildings.

Things to consider during renovation:

• Sound-attenuating underlayment under wood or tile floors
• Reinforcing or leveling subfloors to reduce squeaks and movement
• Acoustic insulation in ceilings or shared walls where allowed
• Solid-core doors for bedrooms and bathrooms for better privacy

Some buildings have specific rules about flooring, such as requiring a certain percentage of area rugs, or specifying approved soundproofing materials. Get these rules in writing before you finalize your scope, or you may be redoing work to satisfy the board.

5. Lead Paint, Asbestos, and Other Environmental Concerns

Pre-war buildings often predate modern safety standards. Depending on the building and scope, you may encounter:

• Lead paint on doors, trim, and window frames
• Asbestos-containing materials in old tile, mastic, pipe insulation, or plaster
• Other materials that require proper testing and abatement

By law and for safety, any suspected hazardous materials need to be handled by licensed professionals. That can affect:

• How demolition is done
• How debris is removed
• How long certain phases of the project take

This is one area where cutting corners is not an option, especially in NYC. Work with a contractor who knows when to test, how to schedule abatement, and how to keep you and your neighbors safe.

6. Details, Moldings, and Character Take Extra Care

The charm of pre-war apartments comes from their details: plaster moldings, ceiling medallions, panel doors, picture rails, and more. Renovating without losing those features takes planning.

Smart ways to preserve (or upgrade) character:

• Careful demolition around moldings and decorative plaster
• Custom millwork to match or extend existing profiles
• Restoration of original doors and hardware where possible
• Thoughtful transitions between old and new elements

Sometimes, it actually makes sense to recreate certain elements in new materials that mimic the original look but perform better (for example, new millwork that aligns with existing moldings but integrates modern storage).

An experienced designer or contractor can help decide what to preserve, what to restore, and what to re-create so the apartment still feels authentically pre-war — just with a layout and finishes that suit modern life.

7. Permits, Boards, and Paperwork Are Non-Negotiable

Pre-war buildings in NYC are often co-ops, and many are in historic districts. That means more layers of approval and oversight:

You may need:

• DOB permits for layout changes, plumbing, or electrical work
• Board approval of your plans, materials, and contractor
• Landmarks Preservation Commission (LPC) review if you’re altering certain exterior elements (like windows in a landmarked district)
• Insurance and license documentation from your contractor for the building’s files

The review process can be strict and time-consuming, but it’s part of working in older NYC buildings. A contractor who already understands co-op boards and NYC permitting can save you a lot of back-and-forth.

8. Plan Your Layout Around the Building’s Reality

In new construction, you often have more flexibility to move walls and systems. In pre-war apartments, the building structure and risers can limit how far you can push the layout.

Common layout realities:

• Structural walls that cannot be moved or enlarged
• Column locations that must be worked around
• Fixed plumbing stacks that constrain bathroom and kitchen relocation
• Window and radiator positions that shape furniture placement

Within those constraints, you can still make a big impact by:

• Opening or widening certain doorways and non-load-bearing walls
• Reconfiguring closets and built-ins for more efficient storage
• Creating better circulation and sightlines to windows
• Reworking kitchens and baths within their existing zone, but in a much more functional way

The goal is to modernize how the apartment lives, while respecting how the building was originally constructed.

Renovating a Pre-War Apartment in NYC? DNB Can Guide You Through It.

Pre-war renovations are some of the most rewarding projects in New York—but they’re also some of the most complex. You’re juggling historic character, old building systems, co-op or condo rules, and modern expectations for comfort and function.

DNB Renovations can help you:

• Assess what’s realistically possible in your pre-war apartment
• Coordinate with architects, engineers, and building management
• Upgrade electrical, plumbing, and soundproofing to modern standards
• Restore or recreate original details so the space keeps its character
• Navigate permits, inspections, and board approvals from start to finish

Whether you’re updating a classic six, reworking a one-bedroom, or gut-renovating a full pre-war apartment, we can help you keep what you love about your old building — while making it truly work for the way you live now.

Thinking about renovating a pre-war apartment in NYC?

Get in touch with DNB Renovations to start planning a renovation that respects your building’s history and brings your home up to today’s standards.