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How Much Does It Cost to Add on a Room?


The popularity of HGTV and Pinterest prove that homeowners like to dream.

Since winning the lottery is limited to only a few people in the country (as are six-figure salaries), the rest of us need to be realistic. So what does it cost in the Northeast, NYC-metropolitan area to make home additions?

Based on prior jobs, we can give you some basic numbers on adding a room to your home.

Cost per Square Foot

When giving a quick estimate, we say it will be about $170-200 per square foot of addition. That includes:

  • The finished shell with roofing

  • Siding

  • Standard windows

  • Interior stairs

  • Standard tub, toilet and sink

  • Framed rooms with drywall

  • Basic electric and plumbing

It does not take into consideration:

  • Special windows

  • Appliances

  • Big tubs and large showers

  • Kitchen cabinets and cabinet pulls

  • Counter tops

  • Bathroom vanities

  • Fancy entry doors

  • Decks, patios and balconies

  • Tile work

  • Hardwood floors

  • Decorative light fixtures and light bulbs

Possible Cost of Home Additions

One-car detached garage that matches the house siding and roof with an electric garage door, a man-door and rafter storage space: $20-26,000

New entry door and stairs with stonework sidewalk: $8-10,000

New two-bedroom, three-bathroom home with one-car garage and basement, including tearing down the house and digging new basement: $470,000

Add a level with two bedrooms and one full bath, one-car garage with new roof and siding, new deck and Florida room: $155,000

Labor Cost

Some homeowners may choose to buy their own material instead of going through a contractor, but you will still need to pay for labor.

To give you an estimate, we charge $50-60 an hour per person for labor-only jobs. A good carpenter can cost between $17-30 an hour, and a helper is $10-15.

To frame a two-car garage with a room above, labor only will cost about $13,800.

Cost of Materials

Add to all of this the prices of materials and the rising labor costs for an experienced crew, and the overall price will continue to increase.

A square of roofing shingles costs $125-175, which covers 100 square feet. Siding with similar coverage costs $250-300 per square foot. Plywood can be anywhere from $15-25 for a 4-by-8 foot sheet, and a 4-by-8-foot sheetrock is $10-15, and 2-by-4s are around $2-4.

Why are costs on TV different?

HGTV and other home-improvement channels are great for inspiration, but it’s important to remember they are first and foremost created for entertainment.

HGTV designers have endorsement deals with suppliers, so they get special pricing for mentions and advertising on the shows. A certain brand or store may offer a TV show a high-quality wood floor at a lower price in exchange for being mentioned on the show. So when you see the price of an item on HGTV or other home-improvement networks, remember that those are lower than what you can expect to pay.

TV shows often have larger crews that can get more done quicker, and inspections are typically passed faster. This means less time is spent working, so lesser labor costs are shown.

Shows are also edited to make the project timeline look faster. They don’t show every minute of drywall spackling, or how the mason grouts exterior stonework for hours or days.

Special orders, clients changing their minds about design decisions, and Mother Nature can also extend the lifeline of projects.

Understanding what costs go into your home addition or remodel will help you decide what is a realistic total cost for adding on a room.

This is not to scare you off doing an addition to your home but to help you see the big picture (and not just the TV-screen-size of home renovations).

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