Full-Service Co-op Design and Renovation

Renovating a co-op apartment in New York City is a different undertaking from any other residential construction project. The buildings have their own rules, their own histories, and their own layers of regulatory complexity — and navigating all of it while keeping a renovation on track requires a specific kind of experience that only comes from doing this work, in this city, for a long time.

At Mammoth, co-op and condo renovation is what we do. As a design-build firm, we bring architectural services, interior design, and project management together under one team — which means every part of your renovation is coordinated from the start, not assembled piece by piece as the project unfolds.

Understanding the Co-op Board Approval Process

Before any wall comes down or any work begins, every co-op renovation in New York City goes through the board. For owners unfamiliar with the process, it can feel like an obstacle. For a team that has done this many times, it is simply the first phase of the project.

The alteration agreement is where it starts. This document defines the scope of work, establishes insurance requirements, and outlines the house rules your renovation must follow. Preparing a thorough, well-organized alteration agreement package — one that addresses the concerns a board is likely to raise before they raise them — is one of the most important things a renovation team can do to keep approval timelines moving.

We coordinate directly with your managing agent and building management throughout this process. That relationship matters. A team that knows how to communicate with building management, understands what a managing agent needs to see, and has a track record with board approvals moves through this phase considerably faster than one that doesn’t.

Our Scope of Work: From Gut Renovations to Targeted Upgrades

Every project starts with a clear understanding of what you actually need—and what your building allows. Whether that means a full gut renovation or a focused kitchen remodel or bathroom renovation, the scope of work is built around your vision, your budget, and the specific requirements of your building.

• Gut Renovations

  For owners who want a complete transformation, a gut renovation strips the apartment back to its structure and rebuilds from there. This is the approach that allows for real layout changes, apartment combination projects, and the kind of comprehensive upgrades to electrical wiring and plumbing that pre-war buildings often require. It’s also the most demanding type of project to coordinate, which is exactly where having a unified design-build team makes the most difference.

• Kitchen Remodel

  The kitchen tends to be the room that changes how an apartment feels most fundamentally. A kitchen remodel at the high end isn’t just about new finishes — it’s about rethinking how the space works, what it connects to, and how it lives day to day. In co-op buildings, that also means working within constraints like the wet over dry rule, which governs where plumbing can and cannot be moved.

• Bathroom Renovation

  A wet area in a co-op involves more coordination than it might appear. Waterproofing, plumbing updates, and the relationship to the unit below all need to be handled carefully and correctly. Our bathroom renovation work takes all of that into account from the start — not as an afterthought once problems surface.

• Layout Changes

• Reconfiguring a co-op floor plan requires working within the building’s structural reality, not just the owner’s wish list. Whether the goal is opening up a living area, creating an additional bedroom, or combining two apartments into one, layout changes need to be resolved architecturally and structurally before construction begins.

Working with the NYC Department of Buildings

Any renovation that goes beyond cosmetic updates in New York City involves the Department of Buildings — permit applications, scheduled inspections, code compliance, and, in more complex projects, board review processes and structural assessments.

Our team handles all of this directly. We know what filings are required, how to prepare them correctly, and how to anticipate the questions that slow projects down when they haven’t been addressed up front. Keeping a project moving through the Department of Buildings approval process is a skill, and it’s one that comes from experience rather than assumption.

Our Team: General Contractor and Specialized Trades

As your general contractor, Mammoth is responsible for every aspect of construction — but the role goes further than that. As a design-build firm, our architectural services and interior design work don’t hand off to a separate construction team. They stay integrated throughout, which means the decisions made in design are understood and protected during the build.

Our network of subcontractors is built around the specific demands of co-op renovation in New York City. That means electrician teams who understand co-op electrical wiring and the constraints of pre-war buildings, licensed plumbers experienced with both aging infrastructure and modern systems, and skilled craftspeople who know how to work within building hours, protect common areas, and communicate professionally with building management. Demolition in a co-op is not the same as demolition on a construction site — it requires care, coordination, and a clear plan for how materials leave the building.

Understanding Cost Per Square Foot

Cost per square foot is one of the most common questions we hear at the start of a project — and one of the most difficult to answer without context. Every co-op renovation is different, and the variables that drive cost are specific: the complexity of layout changes, the quality of finishes and fixtures, the extent of electrical wiring and plumbing updates required, and the building’s own insurance requirements and house rules.

What we commit to is transparency. Our estimates are detailed and itemized, not rounded figures designed to look appealing before change orders surface. When adjustments are necessary — and in a project of any complexity, some usually are — we communicate about them clearly and in advance, not after the fact.

Project Management

A co-op renovation involves more moving parts than most owners anticipate — board approval timelines, construction schedules, subcontractor coordination, managing agent communication, building management requirements, and the dozens of daily decisions that determine whether a project finishes on time and within budget.

From the first board approval through the final inspection, you have a single point of contact at Mammoth who is across all of it. That continuity matters. It means nothing falls between the gaps of a handoff, and it means you always know where your project stands.

What to expect from us

We work exclusively in New York City. Co-op and condo renovation in this market — with its board approval processes, its pre-war buildings, its Department of Buildings requirements, and its particular logistical demands — is what our team is built for. The design-build model means one team, one contract, and one point of responsibility across architectural services, interior design, and construction.

Our track record with co-op board approvals reflects years of understanding what boards look for and preparing packages that hold up to scrutiny. Our work reflects the standard we hold ourselves to on every project — from a targeted bathroom renovation to a complete gut renovation that reimagines an apartment entirely.