Before you begin the design process and determine your budget cost for your additions you need to determine the type of room(s) you need. The room's purpose will help you determine whether you need to build out by expanding the square footage of your home or strengthen your existing foundation in order to build up a dormer, second-story, or two-story addition.

Costs of Building Up vs. Building Out

It’s important to understand the costs involved in building a one-story addition as opposed to a second floor. Building a one-story is less expensive than building a second floor. On average, it costs around $130 a square foot for a one-story addition and $160 for a second floor.

Second Story

When it comes to adding an addition, you can choose between a first-floor or a second-floor addition. If you’re interested in adding multiple bedrooms to your home, we suggest a second-floor addition. At the same time, a one-bedroom or an additional recreational room can be added to the first floor. At Town Islip Expeditors, we draw multiple layouts to ensure the room is large enough.


Dormers add space to the inside of your room when you cant build-out. You can use a dormer to add another window to your home and break up the monotonous appearance of your roof, or to add another whole level to your home. Many people add dormers because they view their current attic as wasted space that provides a lot of floor space, but not enough room between it and the ceiling.


Turn your 3-bedroom into a 4-bedroom at Town of Islip Expeditors. Our architectural designers can add a bedroom to your home in the same style as the rest of the house so that it appears to have always been there.

Suffolk Health Department

If house is built prior to 1973, the town only allows to increase home with the same number of bedrooms. If the home was built after 1973 you are allowed to have up to four bedrooms even if the certificate of occupancy says three. Health Department allows a kitchen, eating area, family room and dinning rooms. Any additional rooms will be called out as bedrooms. Sometime when doing an extension on the home we will need to update cesspool/ septic tank.

parent and child suite

A parent and child suite is an add-on created specifically for additional residents who are moving in permanently and are often senior citizens. At Town of Islip Expeditors, we can design a suite based on your needs including all the amenities that you find in a home with a separate entrance.

Family Room

While most homes have a living room, a family room is a space that’s less formal and better suited for kids, and games are also known as a recreational room. However, if you decide to use this as an all-purpose room, Town of Islip Expeditors can design it to your specs.

Home Gym Addition

Going to the gym can take up extra time, you can save that time with a home gym. Whether you just need to maintain what you have or you're a bodybuilder. At Town of Islip Expeditors, we can design a custom workout gym to meet your budget.

Sunroom Addition

Long Island gets a lot of year-round sunshine, but the heat can make it difficult to enjoy. By adding in a Sun-room with windows as large as floor to ceiling you will be able to soak up rays in perfect comfort. Sun-rooms make great additions to kitchens, libraries, and reading areas next to the living room

Home Office

Whether you need a small, simple space to work or a spacious environment for welcoming clients and hosting meetings, Town of Islip Expeditors can customize a convenient office or study for you.

Cheaper Additions

Basement, Garage Conversions, and Porch Enclosures are less expensive additions that will not strain your budget and will give you the extra square footage you need. At Town of Islip Expeditors, we consider your budget when making suggestions.

Outdoor Kitchen

The thought of turning on the oven in the middle of the summer can seem almost unbearable. That’s where an outdoor kitchen can really help. Add your favorite outdoor living features such as grills, sinks, refrigerators, and more.


Enhance your outdoor areas with some of the following features: Portico's, front porch, overlay roofs. We can show you multiple elevations of your home with these added features.

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