Combining Apartments: Budget and Renovation Costs (Part 2)

cosenza plan AFTER
(Above) Floorplans for two postwar apartments to be combined in an Upper East Side project by Sweeten architect Slavica

Last week, we covered the pros and cons and key considerations when combining apartments. We’re back now with the numbers—coming up with a budget for a unique project like this. Next week: the ins-and-outs of financing, and making sure that the renovation is a sound investment.

How Sweeten Works


As with other renovation projects, understanding the scope is the first step to creating a budget. While combination projects usually run in the hundreds of thousands of dollars, let’s start with a baseline scenario for budgeting purposes. These numbers should be considered a minimum, but it’s worth noting that most combinations will cost more.  Importantly, you should note that if your combination is a vertical one, there will be significant additional costs due to the necessity of a structural engineer and relevant permits. A vertical scope would be outside the baseline scenario outlined below. In Part I, we mentioned that an apartment combination can be as simple as knocking through a door-sized opening and removing a kitchen in a horizontal combination (although it rarely is!). These are the costs that may be associated with that very basic combination:

Combining-Apartments-1 Combining-Apartments-2 Combining-Apartments-3

While the above budget lines provide a sense of the starting line, it is likely that your apartment combination will include further upgrades such as new kitchen and baths, millwork, extensive layout changes, or a new HVAC system. And if you are installing a new air system, you may need to consult a mechanical engineer. These all contribute to higher costs. Take a look at the Budget Basics series for more information that might be helpful in your combination.

While the expense may seem daunting, a combination project results in an incredible space that’s tailor-made for your family. Tune in again next week, when we’ll be back on how to obtain the financing you need to cover the budget! Thanks to Sweeten architect Slavica for helpful input on this post!

Thinking of adding a bedroom or two with all that extra square footage? Check out our post on what constitutes a legal bedroom in NYC.

Sweeten handpicks the best general contractors to match each project’s location, budget, scope, and style. Follow the blog for renovation ideas and inspiration and when you’re ready to renovate, start your renovation on Sweeten.