As today’s DIY trends continue to expand, home addition projects have become the most exciting way that homeowners can build equity. All the television shows make it look effortless to send in your contracting team for a big-time makeover, but is that accurate? What does a home addition cost when everything is said and done?

During a typical remodeling project, there will be problems and unexpected costs. The problem with many remodelers is that they are overly optimistic about what they can accomplish during each phase of the project for their given budget.

 Whether you are planning a home addition, remodeling your kitchen or bathroom, building a deck or patio, the first step is to define the scope of your project. Regardless of what you have planned, it’s vital that you give careful thought to the best way to reach your goals and how much they will cost.

What you’ll learn in this article:

What Is a Room Addition?

The majority of homeowners love the idea of an addition, but they don’t know where to start. Room additions are an excellent way to increase your home’s overall value, add more living space, and even conserve energy. When it comes time to sell, you’ll reap the rewards of your investment in your asking price.

What to Expect When Planning Your Budget

If you’re looking to add to your home, many factors go into deciding whether it’s the right decision. Typical costs for adding onto a house vary depending on what type of addition and how big it is. Costs can also increase if foundation work is mandatory before construction starts. A 20×20 room addition can cost between $400 and $600 per square foot, depending on whether you want a simple structural upgrade or a more premium facelift. That roughly factors out to $160,000–$200,000 on average.

You might be eager to get started on your new home addition, but it’s essential to choose a qualified full-service contractor first. This step is critical because of the complexity of building a structure as large as a home addition. The process includes not just framing and lumber but also permits and inspections from local building departments. You need someone who knows how to navigate all those requirements successfully while keeping the project moving along at a steady pace.

How Much Does a Home Addition Cost - Woodland Builders Blog Hingham, MA - Home Addition Contractors, Room Additions, Contractor for Additions, House Additions

Here are some basic guidelines to manage your budget and your expectations:

Designing the Addition

An architect can help develop the extension and ensure it matches the existing home. This step can total between $5,000–$30,500 or more for complex home additions.

Excavation, Demolition, and Site Prep

Preparing your house for excavation can cost $15,000–$150,000, depending on how much groundwork you need to prepare on your property to make way for a new addition.


Whether you have a small project like a dormer or a big job like an entire second story, most people don’t realize how much they should be budgeting for their roof. Expect to pay around $400–$600 per square for a roof. Steel, slate, support beams, and trusses can all add to this cost.


Each door will add around $2,150+ to your overall budget, while windows can cost between $1400 to $2,400. Ceiling molding adds another $15 to $30 per foot. If you plan to add space to a kitchen, it’s wise to budget for more than just the flooring. You’ll also want to figure in electrical work, plumbing, and appliance costs.


Planning your new addition involves determining your needs’ best layout, style, and materials. The primary function is to transfer loads from the roof or upper floors to the ground. A new foundation can cost $14,000–$52,400, depending on the project’s size and materials.

Before you consider building your own home, make sure that it is allowed, and the process will not be too complicated. Your city or county may have a permitting authority that can give you this information and tell you which companies in your area are qualified to build modular homes. You’ll also need to contact your homeowners’ association (HOA) for any restrictions they might have on construction within the community. The HOA could require approval before work begins.


Average Home Addition Cost Ranges for Each Type

Building a home addition is an exciting yet daunting process. The cost of a home addition can be overwhelming at first; it is important to know what to look for. Depending on the scale of your project, it can be slightly cheaper than building a whole new house or as expensive as moving into a luxury high-rise. The trick to figuring out how much it will cost to construct an addition depends on many factors, but we’ve got some helpful cost ranges for you here that can help.


A kitchen addition is the best way to transform your cooking, entertaining, and family gathering space. Adding another 144 square feet to your kitchen may cost between $125,000 to $200,000 on average. Premium kitchen might include deluxe versions of appliances, cabinets, and countertops.

Guest Bedroom

By adding a 12×12 bedroom to your home, you can add an extra room for guests or even create the space for someone who wants their own private office space. The best part about this addition is that it requires minimal effort and will only take a few weeks of construction time on average. Building a 12×12 bedroom typically totals around $60,000–$90,000


There are plenty of options for housing your cars, such as an underground heated garage or a storage unit. But if you don’t have that luxury, home addition contractors can build you a simple detached garage with no plumbing or electrical work for between $195,000-$250,000. If you’re looking to add amenities, expect a price tag around $300,000 to $325,000 on average.

Accessory Dwelling Unit

When a family member requires extra care, it’s all too common for them to move into the home of their child or grandchild. Unfortunately, this results in some significant structural changes inside your house to accommodate. That’s why so many people choose full-service contractors to help with these kinds of room additions.

Accessory Dwelling Units (ADUs), sometimes called “in-law suites,” usually cover 600 to 750 square feet and include a kitchenette, bathroom, and laundry space. Most homeowners spend a minimum of $250,000 for a full detached suite.

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Can a Home Addition Increase My Equity?

A room addition is a type of building project that you may decide to take on. It seems like a pretty straightforward task—after all, it’s only an extension onto an existing house. But if you want your home improvement to pay off and make you feel more comfortable in your own space, there are some things you need to think about before starting the job. Here are a few estimates of your return on investment after your initial cost:

  • Bathroom addition: 50%
  • Master suite addition: 60%
  • Two-story remodel addition: 66%

For example, say your new master bedroom costs $130,000 from start to finish. When you list it on the market, if you recoup 63% of the cost, you would be able to increase your asking price by $82,000. This alone could make the home additions cost worth it!

How Do I Stay Within My Home Addition Contractor’s Budget?

By listing all the details of a project, you can give yourself or your contractor a basis for providing an estimate. If any changes occur during construction, it is helpful to refer back to this list and see the cost breakdown of the original bid. Ask a few contractors with positive reviews to prepare proposals. Your cheapest option isn’t always the best fit.

You should also check whether your homeowner’s insurance and property tax might increase your home’s new size. Ask your insurer and tax professionals for a comprehensive breakdown.

How Much Does a Home Addition Cost - Woodland Builders Blog Hingham, MA - Home Addition Contractors, Room Additions, Contractor for Additions, House Additions

Now that you’re ready to establish and maintain a renovation budget, follow these guidelines to find a starting estimate:

Architect Fees

An architect will design your addition to flow seamlessly with your existing home. Expect to pay a flat fee between $5,000 to $30,500+.

Site Preparation

The price tag for getting the area cleared and ready for your new addition will cost between $15,000-$45,000. The difference in the budget mainly depends on your desired size and excavation labor.


If you are adding on to your home, you will have to pay for a roof. Roofing can cost roughly $350-$600 per square. You will also have to pay for support beams and roof trusses.

Walls and Ceiling

Vinyl siding and trim will cost about $7-$15 per square foot, insulation is about $8 per square foot, and the drywall installation will run $5-$10 per square foot.

How Much Does a Home Addition Cost - Woodland Builders Blog Hingham, MA - Home Addition Contractors, Room Additions, Contractor for Additions, House Additions


If you are building out, then you will have to pay for the foundation for your addition. Foundations can run anywhere from $14,000-$52,400.


Flooring is one cost that will be mainly under your control since you can pick both the material used and the quality. Expect to pay somewhere between $2,500 and $8,500 for flooring. That cost may go up if you try to match the existing flooring in the rest of the house.


An installed door will run close to $1150, and each window will cost $400-$2,400.


Depending on local regulations, you will have to pay for various permits during the construction. Your builder will give you all the specifics regarding these costs.

Disclaimer: This article is solely for informational purposes and in no way constitutes legal advice or financial guarantees.

How Much Does a Home Addition Cost - Woodland Builders Blog Hingham, MA - Home Addition Contractors, Room Additions, Contractor for Additions, House Additions

Home Addition Full-Service Contractor in Hingham, MA

It’s up to you to do your homework to find a skilled, ethical contractor for additions to your property. The home addition contractors you reach out to should have a clear and measurable process for your home addition project. After you’ve reviewed and signed the contract proposal, you’ll write a deposit check. If you need the perfect partner to help you achieve your dream home, look no further than Woodland Builders.

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