When you love where you live but you need more space, you might wonder what it takes to build an addition. Sometimes deciding to go the addition route is an interim plan before moving onto the next chapter. Or maybe it’s a step toward making your current home a forever place. We’ve listed the considerations to factor into costs and planning an extra room, whether it’s a bedroom, bathroom, or entire living space.
Placement Affects Cost
The total cost of your project largely depends on where you’re building the extra space. When adding up the numbers, keep in mind that the cheapest place to add a room may not be the best choice. The spot that makes the most sense from a usage and flow standpoint may cost more but will likely reap more rewards when it’s time to sell. And don’t forget to figure in the value of how much you will enjoy the extra space based on its size and location.
First Floor Additions
The first floor is the ideal spot for a master suite. With the exception of families with young children, most people prefer to have the master on the first floor. Note that you’ll have excavation costs for a first-floor addition.
Second Floor Additions
Your best bet for the second floor is to add both an extra bedroom and bathroom, or at the very least, an extra bathroom. These rooms are game changers when it comes to maximum return on your investment, especially in older neighborhoods.
Above the Garage Addition
The best usage for this type of addition is as a guest suite or a bonus room. It’s less ideal as a full-time bedroom because of garage noise disturbances.
Bump-out solutions are ideal for extending kitchens, living rooms, or adding closet space. Usually contractors can expand an existing space 3 feet deep by 10 to 12 feet wide without additional foundation work.
Most sun rooms are only practical for three seasons. A four-season sun room requires more insulation, higher grade materials, and heating for winter months. A four-season sun room can cost up to 20% more, so check with your Realtor to ensure which design is more desirable in your market.
Breaking Down Costs
So how do you create a ballpark budget for what your addition will cost? There are so many individual factors to consider. Here’s a general compilation of the elements and some figures drawn from HomeAdvisor and HomeGuide surveys of people who built new additions in the past year.
Architect: 10-17% of total project cost. That’s $2,000-3,400 on a $20,000 addition.
Excavation: $1,200 – $4,110
Foundation: $4,400 – $12,700 per 100 sq ft
Plumbing: $1,500 – $4,000
Electrical: $320 per 100 sq ft
Framing: average of $4,285
Drywall: $1-3 per sq ft and $2 per sq ft for insulation
Roofing: $12,000 – $14,900 per 100 sq ft
Flooring: Depends on material used. Wood is $14 – $32 per sq ft; carpet is $7 – $12 per sq ft; and tile is $15 – $20 per sq ft
Project Cushion: Add at least 10% of total costs as an extra cushion needed for surprises.
Average Project Cost Totals by Addition Size
Below are total addition cost averages using HomeAdvisor’s and HomeGuide’s lower and upper end costs of surveyed home owners who built additions at various sizes in the past year.
Avg Cost (all sizes): $21,000-$74,000
Avg Cost per sq ft: $80-$300
12 x 12 (144 sq ft) size: $11,000-$28,800
20 x 20 (400 sq ft) size: $32,000-$83,200
600 sq ft size: $48,000-$124,800
1,000 sq ft size: $80,000-$208,000
Real Estate Term of the Week:
Excavation Costs: The construction cost that includes digging holes, grading land, and leveling to prepare a site for foundation.