Bolster combined a two-bedroom, two-bath apartment with an estate condition studio in an Art Deco building in Union Square.


Combining apartments may be the easiest way to double your apartment size (and let’s be honest—what New Yorker doesn’t need more space?) 

However, apartment combinations come with their own unique set of challenges. One such challenge many people encounter is when two apartments are severely mismatched. 

In these instances, an architect’s vision and experience with apartment combinations can pave the way to a successful end result. 

“The best outcome when joining two apartments is that in the final result the combined apartment looks seamless, like it was always naturally designed that way,” says Michael Fasulo, architect at Bolster, a New York City-based firm that has designed a relatively seamless renovation experience.

Unlike other design build firms, Bolster provides homeowners with radical transparency and a zero financial risk guarantee. Through the use of a proprietary, data-driven estimating tool, Bolster is able to provide homeowners with a more accurate estimate of overall costs. This is no small feat, given that half of the renovation projects in the U.S. go 40 percent to 200 percent over budget. The firm also boasts a vertically integrated services structure that allows for a full team approach to renovation: The architect, designer, contractor and builder work together from inception to completion of the homeowner’s project.

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NYC Renovation Calculator

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About Bolster's NYC Renovation Calculator: Bolster's Renovation Calculator enables you to easily calculate the estimated cost of a major New York City renovation. All you'll need to know is 1) the scope, complexity, and type of your project, 2) the quality of your desired finishes, and 3) the area being renovated. [Hint: Bookmark this page for easy reference!]

About Bolster: Bolster is a New York City design-build firm that delivers a seamless, radically transparent renovation experience--beginning with a line-by-line cost estimate that empowers you to plan your scope, budget, and schedule.

Standard: The quality of the finish is acceptable with attention to detail but reliant on big-box store sourced cabinetry, MDF etc. 

Mid Range: The quality of the finish is good (grade A) with attention to detail but reliant on big-box store sourced cabinetry, MDF etc.

High Range: The quality of finish is high (grade AA) and customized with fine finishes and materials being used that can last years, if not a lifetime.

Upscale: The quality of finish is the highest possible (grade AAA) and labor-intensive, with every surface bespoke, new, and beautifully finished.

Low: Simple design, no layout or structural changes, elevator in building.

Medium: Average design, moving of some systems and/or structural changes, no elevator in the building.

High: Complex design, complicated engineering, lots of logistics (e.g. boom lifts, suspended scaffolds, etc.), dangerous working conditions.

Small: Changes to surfaces only (e.g. painting, tiling).

Medium: Small + Changes to the finishes themselves (e.g. removing plaster, replacing flooring etc).

Large: Small + Medium + Changes to the building's infrastructure (e.g. replacing all systems, walls, floor joists etc).

In instances where apartments are severely mismatched, both are usually gutted to make them work together. 

“Most of the time, clients usually end up doing work to both apartments,” says Bolster architect Agustin Ayuso. “We, the architects, work hard to make sure we can make the updates blend in as seamlessly as possible.”

Anna Karp, co-founder and CEO of Bolster, recommends asking the building management to share the specifications of the original apartments, as well as any prior renovations to the space, in order to better match the flooring, finishes, light fixtures, and other details.

“Sometimes, in condos that were developed recently, it's a good idea to approach the board to see if there are floorboards left over, or any other fixtures that may have been purchased wholesale and that would help with matching,” Anna says.

 Bolster combined a 1,750-square-foot, three-bedroom, three-bath contemporary condo in Tribeca.

Bolster combined a 1,750-square-foot, three-bedroom, three-bath contemporary condo in Tribeca.

Another reason to engage an architect for your apartment combination is that they are able to think of your new apartment holistically, giving you more options and ensuring a seamless end result.

You know exactly how many shelves you want in the new walk-in closet and where you want the stairs, but an architect’s trained eye may help you explore options that you’re unable to see or didn’t know were available to you. 

“Combining apartments usually requires some rearrangement of the parts in either unit. It seldom makes sense to just knock down one wall,” Agustin says. “Architects plan the layout and take into consideration a lot of things that clients usually miss on their own: outside views, accessibility, circulation flow, storage, and egress, to name a few.”

Pro Tip:

With more than 50,000 square feet renovated in NYC, Bolster understands how to guide New Yorkers through any renovation challenge, from navigating Landmarks to recreating pre-war details, and gives them full visibility into project milestones. "Bolster is the only renovation firm to offer a fixed-price cost up-front. Once we perform due diligence and verify the existing conditions of your property, we absorb unforeseen project costs," says Bolster's CEO and co-founder Anna Karp. Ready to start your renovation? Learn more >>

Most of the time, Agustin says, the larger of the two units being combined needs to be re-thought entirely as a whole. 

“For example, we've done several combinations where one of the previous living rooms becomes a master bedroom, with the kitchen becoming a master bathroom or walk-in closet,” he says. 

If you’re thinking this sounds like a puzzle, it’s actually a pretty good analogy. 

“The best way to think about combinations is to see them as jigsaw puzzles where rooms have to be ordered considering the rules that the co-op and the condo may have, and also considering structural elements and window availability,” Anna says. 

A skilled architect also knows the limitations—and possibilities—available with different types of buildings. 

“Some newer buildings in NYC, mostly condominiums, have written into their by-laws that combining apartments may allow the owners to incorporate parts of the public hallway into their units. This is something that is much harder to do and get approval for in older buildings, mostly co-ops,” Agustin says. 

The most successful combinations are thoughtfully designed so the final sequence of spaces appears as if you hadn’t done a thing. 

“The new, combined apartment feels as if it has always been the way it is from the start,” Michael says. 

Finally, architects know where to save you money. According to Agustin, the combination design and construction costs are about the same as doing a renovation—but there are exceptions.  

If your apartments are severely mismatched but you’re being frugal and want to preserve one unit, “Use the newer one as the design baseline. Try to match the doors, trims, and other details,” says Michael. 

Another potential large additive to cost is a staircase. In short, vertical combinations are more costly (plus, they involve more planning and a longer approval process). 

Though duplex combinations are rare, they are not unheard of. Therefore, if you’re doing a vertical combination and are being cost-conscious, Michael recommends trying to find a place for the stairs in between beams that doesn’t involve major re-framing work. 

On a happy note, apartment combinations can prove to be a good financial move. 

“Combining can be a smart investment decision, depending on the area, as the property as a whole may be worth more than its parts,” Anna says. 


The Bolster Smart Renovation Zero-Risk Guarantee

How can a design-build firm guarantee a Zero-Risk renovation?

Bolster has pioneered Smart Renovation. We apply quantitative analysis along with our proprietary technology solution to identify and quantify the performance risk on every renovation project. The result is a personalized strategic approach to each renovation that allows us to absorb 100 percent of the homeowner’s risk. Your home will be beautifully designed, and delivered on-time and on-budget. That is our guarantee.

Smart Renovation & Zero-Risk means that Homeowners are now free to dream.

To start your major home renovation project visit

The Bolster Promise video


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