How Much Will It Cost To Build Your Home Addition?
Understand cost and budgeting factors for your addition
Here’s How Much a Simple Addition Will Cost
SMALL ADDITION
100 – 300 SQ FT
$150,000 – $200,000
MEDIUM ADDITION
300 – 600 SQ FT
$200,000 – $300,000
LARGE ADDITION
600 – 1,000+ SQ FT
$300,000 – $650,000
A simple addition is the most basic and affordable way to expand your home’s living space. It typically consists of a rectangular room with standard construction – four walls and a roof – added to your existing house. Common examples include a bedroom, office, or family room.
This type of addition works best on level ground with minimal excavation needed. The straightforward design keeps engineering and construction costs low. A side bedroom with a crawl space foundation is a typical example.
Common features of a Simple Addition include:
- Single level on the ground floor
- Slab or crawl space foundation
- Bedroom, living room, or office
- No major excavation
- Minimal plumbing & electrical
- Basic structural design
Here’s How Much a Standard Addition Will Cost
SMALL ADDITION
100 – 300 SQ FT
$200,000 – $300,000
MEDIUM ADDITION
300 – 600 SQ FT
$300,000 – $650,000
LARGE ADDITION
600 – 1,000+ SQ FT
$650,000 – $1,200,000
A standard addition is more complex than a simple room addition because it typically includes utilities like plumbing and electrical work. Examples include bathrooms, kitchens, or laundry rooms.
These projects require more extensive engineering and design work. For instance, a kitchen addition needs detailed planning for cabinet layouts and appliance placement. These extra complexities increase both design time and overall cost.
Common features of a Standard Addition include:
- Basic shape with some variation
- Slab or crawl space foundation
- Bathroom, kitchen, or laundry room
- Requires some excavation
- Lighting fixtures
- New flooring
Here’s How Much a Complex Addition Will Cost
SMALL ADDITION
100 – 300 SQ FT
$250,000 – $400,000
MEDIUM ADDITION
300 – 600 SQ FT
$400,000 – $880,000
LARGE ADDITION
600 – 1,000+ SQ FT
$800,000 – $1,500,000+
A complex addition involves extensive engineering and specialized construction due to its scope or unique challenges. These projects typically:
- Significantly alter the existing home’s structure
- Require comprehensive utility systems (plumbing, electrical, and HVAC)
- Feature specialized architectural or design elements
Examples include historic home renovations, multi-level additions, and accessory dwelling units (ADUs).
- 2nd story, basement, or multi-level
- Complex, custom shape
- Multiple rooms & functions
- New flooring
- Updated backsplash
- New lighting fixtures
- Custom features
What Affects the Cost of Your Home Addition?
There are several factors that may influence the cost of your home addition. Here are the 3 most important ones to consider when planning your project.
1. Level of Customization
The more customized your home addition designs, the more the project will cost. Custom work requires more labor and higher-quality products, so be prepared to pay more for custom features.
2. Labor & Construction Administration
Some homeowners prefer to have a more involved role in organizing or constructing their home addition. Others simply want to hire a contractor who will handle the entire process. The more involved your contractor is in managing and constructing the project, the more expensive it will be.
3. Product & Material Quality
Nobody wants to build their home addition just to watch it fall apart a year later. However, high-quality materials and craftsmanship for your addition often come at a higher cost.
Ready to Get Started?
Step 1
Schedule a call with a Design Consultant
Step 2
Invite us to your home for an initial evaluation
Step 3
Align on budget and meet to discuss the design
Frequently Asked Questions
What is Lamont Bros.’ process for a home addition?
As a design-build firm, we work with homeowners to thoroughly plan out their home addition project before moving them to construction. Check out our Process Page to learn more about the design-build experience.
Can you keep the cost of my home addition within my budget?
Absolutely. At Lamont Bros., we’re committed to keeping you in charge of the cost of your home addition. One major benefit of the design-build process is that you’ll know exactly how much your addition will cost before it ever begins construction.
Do you offer financing for home additions?
Although Lamont Bros. does not directly offer financing for home addition, we do partner with several lenders to provide our clients with a variety of financing options. Whether you need $50,000 or $500,000, we’ll work with you to find a lender who meets your financing needs.
How is Lamont Bros. different from other contractors?
Lamont Bros. is a design-build firm, meaning we offer full-process remodeling services and oversee both the design and construction of a remodel. Design-build firms are but one of many types of contractors available to you.
To ensure that you’re able to hire a contractor who meets all of your home addition expectations, check out our 3-Step Guide to Choosing a Remodeling Contractor.
Is a home addition a good investment?
When designed well and kept to a reasonable budget, a home addition can be a great investment in the value of your home and the quality of your life while you live there. Market data suggests that a home addition can add up to 80% of its cost back to the home’s value upon completion.