The Average Cost Per Square Foot to Add an Addition to Your House

When setting up plans for home renovation, it’s best to create a realistic budget and stick to it. The national average for an addition is around $40,000. However, the cost can fluctuate from $250 to $300 per square foot according to size, location, materials and the type of room you are planning to add. In order to calculate the cost per square foot for any home addition, you must break it down by its core components.

Not every type of addition requires detailed plans and drawings from an architect, but it is something to consider at the beginning of any project. A basic floor plan of your addition may help you to visualize the scope of the project as well as the potential obstacles that you will face. Once you have the basic elements listed, consult your contractor regarding the project.

Keep in mind that rooms with simple designs, such as living rooms and bedrooms, will be much easier to plan than kitchens and bathrooms, as these rooms are meant to meet specific needs and functions. If your contractor suggests that you get official architectural plans, take the time to shop around for the best price and design. These plans can cost anywhere from 10 to 17 percent of your total project budget, and you can expect to pay approximately $1 to $5 per square foot.

After the addition is planned and excavated as needed, the walls, flooring and roofing must go up. Each of these elements of an addition can fluctuate in price according to which materials you choose. For a traditional home with wood framing, you can pay about $15 to $30 per square foot, but creating walls from brick and mortar, concrete or another material can vary in price. Flooring options can range from laminate and tiles to hardwood or carpet, and each type of flooring has a varying price range, so take the time to find an affordable option for your addition that matches the existing flooring in your house.

Other aspects of basic construction for which to budget include the exterior siding, drywall, insulation and roofing. You can expect insulation and drywall costs to be similar no matter which supplier you choose, with insulation costs at about $2 per square foot and drywall at about $9.80 per 4 foot by 8 foot sheet. A standard choice for the exterior is vinyl siding, which costs about $7 per square foot. Roofing, however, can get much more expensive. Asphalt shingles or galvanized metal flashing can cost from $80 to $100 per square foot, and other materials, such as slate, can be even more.

The last aspect of an addition’s budget to consider is the utilities that power the house, such as electrical, water and HVAC hookups. These aren’t usually measured by square feet but should still be included in the overall budget as a standard cost. Electricians generally charge by the hour, and with wiring not installed by square feet, they usually cost about $50 to $100 per hour. Rooms that require additional piping for water are usually kitchens or bathrooms, which typically cost $30 more per square foot than a traditional room.

There are many other components to include in your budget, so communicate with your contractor regularly regarding your needs and expectations for this project. A normal room can cost from $250 to $270 per square foot, while a kitchen or bathroom addition can cost up to $300 per square foot. If you are concerned about the budget for your project, take the time to adjust the scope of your project so that expenses are trimmed as needed.