The Winning Bid

Here’s how much it costs to renovate a prewar 3-bedroom co-op in Cobble Hill, Brooklyn

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What goes into an extensive renovation of an apartment in a historic New York building—and how much does it cost? Bolster, a New York City company that matches homeowners to reliable contractors and architects, vastly simplifies the bidding process, and financially guarantees that each project is delivered beautifully, provides an in-depth look at one such project: the renovation of a three-bedroom, one-and-a-half bathroom co-op in a turn-of-the-century Cobble Hill limestone building.

The apartment owners, a young professional couple for whom this is their first home, wanted a gut-renovation of the master and hall bath, re-plastering of all walls, new flooring, and custom carpentry before they settled into their new digs. Bolster contractor Aaron Borenstein of Home Evolutions supplied the winning bid at $223 per square foot, which included everything that went into the project, from materials to insurance to architect fees.

Click on the image above to see the real-life detailed bid. You can view a photographic diary of the renovation on Bolster’s site.

Below, Borenstein breaks down the noteworthy aspects of the job, and how, by working with Bolster contractors and architects, you can make your own project go smoothly and transform your space into the home you dream of.

The age of your building matters

If you live in an older building, you may need to anticipate challenges due to structural deficiencies that have arisen over time, as the property naturally settles, Borenstein warns. One such issue has to do with flooring: “Buildings settle and floors settle,” he says. “It may not be just about putting down wood floors—you’ll have to repair the floor below it first.” Installing a mud floor and pan—a sub-surface for tiling—in the Cobble Hill apartment’s master bathroom, and then installing a natural stone tile floor over it, cost $3,210; similar work in the hall bath was $2,247. In the home’s second bedroom, removing old flooring and installing new wood flooring cost $3,317.

Adjusting floors means changing door heights, too; the owners paid $910 to raise the hall bathroom’s doorway by one foot. Furthermore, when renovating an older apartment, you’ll need to inspect for hazardous materials like lead paint and asbestos. Before renovation begins, owners need a work permit from the Department of Buildings and have an asbestos inspection conducted—which is where an expeditor, who helps navigate city bureaucracy, comes in. (For this project, expeditor fees came out to $2,500.)

Priming the moldings

A Bolster worker primes the new moldings.  Photo credit: Bolster

A home with historical cachet is always appealing, but if your apartment is landmarked, there may be rules against replacing your windows—whether they’re well-insulated or not, Borenstein says. Here, homeowners replaced two windows in the second bathroom, for $2,471.

Electrical wiring is another major consideration, as many older buildings have dangerous aluminum wiring needs to be replaced, Borenstein says. Over the course of a large-scale renovation, you might have to replace all wiring back to the electrical panel, and replace the panel itself as well. The cost of this kind of undertaking can amount to a significant percentage of the project.

In the case of the Cobble Hill renovation, Borenstein says that the wiring was the biggest challenge; all told, the electrical costs for this project amounted to $10,539. To tackle this obstacle, the crew opened some of the apartment’s walls in order to put new wires through; this simplifies the task of inserting new wires, but requires replacing sheetrock.

Make as many decisions in advance as possible

The Cobble Hill apartment owners hired Bolster architect David Yum, AIA, who guided them with their design decisions before the project was underway.

Borenstein says that when many clients commit to a renovation, they simply draw up a floor plan and submit it to the Department of Buildings, “but when the customer does their due diligence before the project starts”—meaning they select and commit to details like fixtures, tiles, and other design features before the project begins—“the process goes more smoothly.” Though it takes time to plan, he notes, the advance preparation is worthwhile.

So what might you need to consider ahead of time? For this project, the homeowners took time to select plumbing fixtures, tiles, finishing, seals, and crown moldings; they also determined what types of lights to put in and the locations of light switches, as well as the placement of appliances. Borenstein suggests that you think about whether rooms like the kitchen are comfortable to work in, or could use some rearranging—being as methodical as possible is the best policy, he says.

Cobble Hill Molding Detail

Close up of precision-detail, Level-5 finish on classic ceiling molding.  Credit: Bolster

Thoughtful, detail-oriented decision-making also makes for a more beautiful space. Creating the custom cabinetry for the Cobble Hill apartment was one of the most challenging, and enjoyable, aspects of the project, says Borenstein. New crown molding in the living room was accented by cove lighting, which gave the space a relaxing, warm glow—these touches cost $6,254. Millwork around the fireplace brought it back to life, Borenstein observes; this work amounted to $4,534. Plus, a so-called “level-5” finish—a process of spackling, sanding, coating, and painting outlined here—made for the smoothest of finishes; all painting amounted to $8,561.

Such details meant that the pre-construction period lasted a couple months; "it's a misconception that arriving at a fair price is an art form, but it’s actually a science,” says Bolster founder and CEO Fraser Patterson. “You have to structure a project like this to ensure nothing goes wrong, and no two projects are ever the same." This is where the Bolster Fair Pricing Method—a scientific approach to arriving at a fair price for both homeowners and contractors, whatever the renovation—comes in. 

If you don’t want to stay on site, hire an architect

Even after you go to the showroom and selected all your new appliances, fixtures, and finishes, it still pays to hire an architect. Without one, Borenstein says, you won’t be able to leave the project site: “When you pick out your tile, you won’t have a tile layout; you’ll have to go over it with the contractor.”

An architect will sketch out an exact formula beforehand, presenting images of your future apartment that leave no design or construction questions unanswered. “Architects lend a certain rigor to the process of setting up the project properly,” Borenstein says.

“Just because someone may be able to go shopping and pick out a nice pair of shoes and pants, they don’t necessarily know how to put together a great outfit,” says Patterson. Taking all the design elements homeowners have selected, and creating a synthesis throughout the entire space, “is the domain of an architect,” he says. “That’s money very well spent." 

Borenstein agrees that collaboration between contractor and architect is essential: “There should be mutual appreciation between construction and design.” Architect fees usually amount to ten to twenty percent of the total renovation cost; here, that meant $25,000.

Understand insurance policies

Borenstein notes that the plumbing on the Cobble Hill renovation was a large expense because the crew had to move risers—pipes that serve entire buildings—in the process of expanding the master bathroom. Plumbers, especially when they do such work in large buildings, have to carry huge insurance policies, he says, because liability is significant in the case of damages.

Cobble Hill Millwork 2

The new moldings were cut on-site for precision fit.   Photo credit: Bolster

Insurance can be a thorny issue: Bolster’s website includes a cautionary tale of a homeowner whose contractor accidentally cut through a property’s pipeline and caused a flood. The mishap forced the owners to vacate and halt the renovation, but even worse was the fact that the contractor’s general liability insurance policy was insufficient to cover a neighbor’s property damage claim—which cost the homeowners an additional $55,000. In this instance, the contractor identified themselves to the insurer as a carpenter--for whom general liability insurance is a lower percentage of the project costs--when in reality, they should have been insured at a higher rate. When the contractor cut into the pipe, the insurer didn't pay out, and the homeowners were left with the bill. 

Such incidents are why a Bolster Contractor’s insurance costs are higher, but the correct amount of coverage is crucial, Patterson says. He notes that though some clients shop for the cheapest contractor, there shouldn’t be big differences in cost if the insurance coverage is appropriate to the scale of the project. Part of the value Bolster adds to their customer’s projects is to reveal the logic behind these direct and indirect insurance costs. For the Cobble Hill project, the general liability insurance policy was $6,159, and workers compensation insurance was $3,867.

Factor your buildings’ logistics into renovation costs

There are a number of factors that can add to renovation costs that might not occur to homeowners—for example, if you live in a walk-up, expect additional fees for the transport of materials up and down stairs. Even in an elevator building, the elevator’s location—whether it’s five feet from the front door, for instance, or down a long corridor—poses another variable. “Crews can spend a quarter of a day bringing in materials,” Borenstein points out, “which can cost a few thousand dollars in delivery fees.” Protecting floors and materials, too, as well as handling garbage removal, adds to the costs; for this renovation, which was in a walk-up building, these fees amounted to $3,900.

Just as every project is unique, so is every building, much to the chagrin of owners. But in the case of this renovation, the owners—thanks to plenty of advance planning, and a thoughtful collaboration between contractor and architect—were able to move into their revamped home right when they had hoped to: just before the Christmas season.

Every year, New Yorkers waste over $700M following the usual renovation process. Bolster is different, using a scientific approach to match you with the highest-quality professionals and financially guarantee your project is delivered beautifully for a fair price - all at no extra cost.

To start your major home renovation project, visit or call (929) BOLSTER.


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