The Winning Bid

Here’s how much it costs to renovate and expand a house in Hudson Valley, N.Y.

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For obvious reasons, most New York City renovations involve reconfiguring existing space rather than expanding an apartment or brownstone’s footprint.  Which is why even experienced urban renovators may be unsure about what’s involved in a major expansion of a weekend or suburban home outside the city--or how much it should cost.

“Higher-end towns around the city suffer what’s known as ‘driveway pricing,’ in which local contractors typically quote higher prices to owners who appear affluent,” says Fraser Patterson, founder of Bolster, a New York City company that has designed a transparent and enjoyable process for area homeowners doing major renovations. “Our process makes it impossible for our general contractors to inflate their pricing.”

That’s why one couple in Garrison, N.Y.--a scenic town on the Hudson River 50 miles north of the city—recently sought Bolster’s help to find a contractor to build a new wing onto the three-bedroom, two-bath, 4,000-square foot home they share with their three children.  Besides adding about 1,000 square feet to the house, they’re also making extensive updates to the property’s exterior as well as some upgrades to the interior, including a bathroom renovation, new millwork, new doors and windows, an HVAC system, and new lighting.

The Georgian exterior of this Garrison, N.Y. colonial will get a Northeastern makeover, including Nantucket-style cedar shingled roofing and siding, and copper accented windows.

Before contacting Bolster, the pair already had plans in hand from an architect who had created a beautiful design—but unfortunately, it was also almost twice their initial budget of $600,000. The couple then worked with a Bolster architect and contractor to revise the project and bring the price down.

“They made the decision to expand the footprint of the house and get the things they really want, while keeping options open to upgrade further over time,” explains Bolster co-founder Anna Karp.

Bolster contractor Isidore Castiglia ultimately supplied the winning bid at $765,063. (Click here to view the bid in detail.)

The renovation will begin in late February, once the worst of the winter weather is over, and take about six months to complete. Fortunately for the homeowners, they’re able to remain in the house for the duration of the project, as the house’s size means they can easily remain out of the way of construction.

Read on to find out how they prioritized their wish list for the renovation, and what it will cost to expand and upgrade their home.

Creating infrastructure to expand the home (and make it easy to build upon later)

The most significant aspect of this renovation is the construction of a larger garage, with a new master suite—including a bedroom, bathroom, office, dressing area, and laundry room—situated above it. Because the initial project plans contemplated a renovation well beyond the homeowners’ $600,000 budget, the clients first met with Bolster architect Agustin Ayuso to brainstorm ways of expanding their home at a more affordable cost.

“Agustin presented alternatives with a fresh set of eyes, to help them maximize their space,” Karp says. For instance, one of the homeowners is an avid car collector, and wanted to install a car elevator in the new garage in order to store cars on two levels. To save money, the Bolster team will build the necessary infrastructure for an elevator so that the project can be easily updated at a later date.

This is the approach for the renovation as a whole: construction will focus on creating infrastructure that will make it simple for the homeowners to make further upgrades in the future. As for what will be added to the home now, the first step in creating the expansion is the demolition of the existing garage ($15,000). Creating a garage and master suite from the ground up then requires excavation to build the foundation for the new wing ($6,000), concrete footings for the foundation ($6,000), and poured concrete walls ($8,000). Framing—that is, the skeleton of the addition to the home—is a big-ticket item, costing $35,000.

Another major project for the home’s infrastructure is installing the electrical ($41,000), plumbing ($35,000), and HVAC ($15,600) and tying them in to the home’s existing systems. This work is crucial to do now, Karp says: “It would be disruptive later on, because it means opening walls and would require the homeowners to close sections of house.”

Luckily, the home is large enough that the owners can live here while renovations are underway. 

When the project is complete, there will be total continuity between both sections of the home. “The connection [between the two wings] is made with and at the garage, which is brought forward, allowing for a transition which really is not noticeable,” Castiglia says.

Opting for understatement on the exteriors  

Creating a seamless transition between the old and new sections of the home entails making changes to its entire exterior. As of now, the outside of the house is eye-catching, with ornate details like Greek columns at the front, but the homeowners want a façade that’s a bit subtler. As Castiglia explains, “We’re going to get it to look more like a Northeastern home instead of a Georgian colonial.”

This involves a new roof made with Nantucket-style roofing and siding, with cedar shingles  ($47,000), and copper standing seams around the windows ($15,500). Karp notes that copper is usually a high end option for roofing, but it’s a great value at the moment, bringing the project bid closer to the homeowner’s original budget. Along with the shingles, new gutters must be installed ($4,000). Further changes to the home’s exterior include new siding ($32,500) and stone veneers ($45,000), making an elegant, but not grandiose, first impression upon visitors.

A cupola ($4,221) will be incorporated into the exterior of the new wing, to bring more light into the master suite area; the front door will be framed by a portico ($16,885), creating a more striking entrance to the revamped house.

Making budget-minded decisions about interior details

The initial design for the interiors of the new wing featured extensive custom work, including bespoke cabinetry and light fixtures. Ayuso helped the homeowners determine what they wanted to keep, and what could be re-envisioned to lower the project budget. Now, instead of custom cabinetry, tiles, and bathroom vanities, the homeowners will use off-the-shelf products, which helps to lower costs.

“The owners wanted a big price reduction, and our suggestion was to reduce by diminishing the most expensive materials,” Ayuso says.

However, Karp adds that it wasn’t worth it to jettison all the expensive details the homeowners had initially chosen, as changing some of the fixtures and fittings would incur more design costs.

Ayuso agrees. If you find yourself with a renovation budget that goes well beyond what you expected, “leave the things that required a lot of design input, or you’ll end up spending more redesigning,” he says. “Cut things you could easily do later.” In this case, the homeowners decided to wait on the car elevator as well as a back patio.

The Bolster team was able to lower costs on features of the new wing’s interior like decorative trim ($35,000) and bathroom tile ($17,000), by opting for high quality, but less bespoke materials. The master suite, for instance, will feature decorative white oak beams throughout, a better value than the reclaimed material included in the original design. The installation of wood flooring in the suite will cost $26,000, and painting the new wing of the home will run $15,500.

Elsewhere, Ayuso says, “We diminished the scope of work on finished woodwork.” Custom closets and millwork were slashed from the budget, to be upgraded over time.

“They’ll have the closets, doors, and flooring done, but fancy shelving, sock drawers, and tie racks can be easily assembled in the shop later and put into place over a couple days,” he explains.


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 bolster.us 

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Should you hire an architect or a contractor first? 

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