How much does a garage extension cost?
How much does a garage extension cost?
$60 – $120 average cost to extend per square foot
$9,600 – $24,000 average cost to add another bay / stall
Garage extension cost
A garage extension costs $60 to $120 per square foot, or $9,600 to $24,000 on average to add another vehicle bay to the existing structure. The cost to extend a garage with a second-story addition is $60,000 to $200,000+, depending on the room size and features.
|Project||Extension size (feet)||Average cost|
|Extend 1-car garage to a 2-car garage||8' x 20'||$9,600 – $19,200|
|Extend 2-car garage to a 3-car garage||10' x 20'||$12,000 – $24,000|
|Expand 1-car garage to 3-car garage||20' x 20'||$24,000 – $48,000|
|Add extra space to a garage||4' x 20'||$4,800 – $9,600|
|Build room extension over garage||20' x 20'||$60,000 – $200,000+|
Cost breakdown to expand garage
Expanding a garage requires the same construction elements as building a new garage. However, expansion costs more per square foot than new construction due to the demolition involved and the challenges of working with the existing structure. The total cost depends on the size, features, and finish levels.
Garage expansion design and preparation costs
Design – A garage expansion typically requires an architect or engineer to assess the current structure and design a construction plan that works with the rest of the home. The architect will also ensure the expansion follows local building codes and zoning and setback requirements.
Architect fees are 10% to 20% of the construction cost for a garage extension or addition.
Hiring a structural engineer costs 1% to 5% of the construction cost. Architectural firms typically include a structural engineer's plan in their estimate.
Permits – Construction permits cost $500 to $2,000+. A garage expansion often requires multiple permits and inspections, depending on the project scope.
Demo – Demolition costs $4 to $10 per square foot, depending on the location and amount of structure being torn down.
The cost to remove a wall is $500 to $2,000 for a non-load-bearing wall.
Removing a load-bearing wall costs $4,000 to $10,000.
Garage extension building costs
Labor – General contractors hourly rates are $50 to $150per hour. Many contractors charge a percentage fee of 10% to 20% of the total project cost instead.
Foundation – A concrete slab foundation costs $5 to $14 per square foot.
Framing – Garage framing costs $10 to $35 per linear foot for the framing alone, or $32 to $56 per linear foot for framing and drywall.
Electrical – Hiring an electrician costs $50 to $130 per hour, with a $100 to $200 service call fee that typically covers the first hour.
Electrical outlet installation costs $150 to $350 for labor and materials. Most states require at least one outlet per vehicle bay.
Plumbing – Plumbing costs $4.50 per square foot to install rough-in plumbing pipes. The cost to install new plumbing fixtures is $300 to $800 per fixture.
Roof trusses cost $5 to $14 per square foot installed.
Roof replacement costs $3 to $6 per square foot, or $300 to $600 per square (100 SF).
Siding – Garage siding costs $3 to $11+ per square foot, depending on the type.
Gutters – New gutter installation costs $5 to $15 per linear foot.
Garage expansion remodeling costs
Garage remodeling costs depend on the finish level of the space. Expanding an unfinished garage requires less labor and materials than a garage with insulation and drywall. Converting the garage to a full living space with windows, HVAC, and other features costs the most.
Garage insulation costs $0.50 to $3.00 per square foot installed, or $800 to $5,100 when insulating the walls and ceiling of a 2-car garage.
The average cost to drywall a garage is $800 to $5,000, depending on the size and finish level.
Garage door installation costs $550 to $1,800 for labor and materials. A new garage door is typically needed when expanding the garage width but may not be necessary when expanding from the back.
Installing a new window costs $150 to $1,000 per window. New skylight installation costs $1,600 to $4,200, depending on the size.
The cost to convert a garage to a full living space is $5,000 to $50,000+, depending on the size.
Garage extension vs. bump out cost
A garage extension costs $9,600 to $200,000+, depending on the size and whether extending up or out. A bump-out costs $5,000 to $30,000 on average. A bump-out extends a room's square footage by attaching a smaller room, requiring less damage to the existing structure.
The existing roof is typically left intact when adding a bump-out.
Consider a bump-out for extra workspace or when needing extra feet for a longer vehicle.
Cost to tear down and rebuild a garage
The cost to tear down and rebuild a garage may be less than extending the existing structure, depending on the existing garage's age and condition.
Tearing down a garage costs $2,500 to $11,000 on average.
A new garage costs $20,000 to $50,000+ for labor and materials, depending on the size, type, and features.
Building a prefab detached garage typically costs less than building an attached garage.
Cost to build an extension over garage
The average cost to build an extension over a garage is $60,000 to $200,000+, or $150 to $500 per square foot, depending on the size and features. Building up instead of out is often necessary for homes with limited lot space or strict zoning and setback requirements.
Building up often requires foundation and structural reinforcement, especially in older homes.
Building a finished space over a garage adds to the home's square footage and typically increases its value.
Is it worth extending a garage?
Extending a garage is worth it for some homeowners, depending on your location, budget, and existing home and lot. A garage extension may not increase your home's value as unfinished spaces do not count as home square footage. Still, the extra space may attract more potential buyers when selling the home.
Getting estimates from garage builders
Before hiring a garage addition contractor to extend your garage, be sure to:
Get at least three estimates to compare.
Hire a company that is licensed, bonded, insured, and has been in business for 5+ years.
Look for a contractor or firm specializing in garage expansions or home additions.
Browse their reviews on HomeGuide and Google.
Ask for references with contact information.
Ask for a portfolio of past similar projects.
Check local regulations before extending or renovating the garage. Some cities require a specific amount of covered parking, and most areas have zoning and setback requirements.
Get a detailed contract and warranty in writing before the project starts.
Never pay in full before the project is complete. Follow a payment plan instead.
Questions to ask
What experience do you have with garage extensions?
Are you licensed, bonded, and insured?
What does the estimate include?
What additional costs could come up during the project?
How long will the project take?
Who will be doing the actual work?
Can I stay in my home during the project?
What permits do I need, and do you handle the permitting process?