Building a garage addition can be an expensive home addition. A garage addition might be cheaper than other home additions but the question is whether the value justifies the cost for space that will only be used to store cars and/or stuff.
If you're thinking about building a garage addition, here are some of the things you want to take into consideration when planning your project
- How much garage space do you need (want)? Many new homes now include a third car stall for a golf cart or storage when there's no basement. Do you want extra space for a workshop, gardening center or storage? If you have any thoughts about buying a recreational vehicle in the future, consider the extra height they will need.
- What type of garage will your local zoning laws allow? There are often restrictions on:
- Percentage of land that buildings can cover. This includes your house, garage and other buildings like a shed.
- Distance between buildings and the property line. When I put an addition on my Victorian home, I had to get a variance to continue the existing line of the house which was only nine feet versus the required 10 feet.
- Access to the street.
- Would you like to attach the garage to the house? This is often a less expensive option but it's not as straight forward as some homeowners think. The land may not be level and there are zoning laws that control the distance between your home (and now garage) is from the property line.
- Where will you put the garage and driveway? Will you see the garage doors from the street or have a side wall face the street with windows that make it look like another room? Do you want a driveway where you can turn around so you don't have to back out onto the street? And don't forget that open car doors need extra clearance.
- Will you add living space over the garage? This is a cost effective solution once you've put in the foundation and a roof and you have the option of finishing this space at a later date.
- Do you plan to build it yourself or hire a professional? It might seem tempting to DIY a garage addition because it's much smaller than a house but in reality, it still requires the same steps to be followed for a lot less square footage … with the exception of finishing the interior. You'll be better off if you hired someone to handle the structural work while you focus on the finishing details. That's what this Newburyport, MA homeowner decided – he did the electrical, plumbing and all interior finish work for the living space on the second floor.
The American Housing Survey in 2009 showed that 66% of homes have a garage or carport. This number might be skewed by new construction because most new homes include a garage, where costs for excavation, foundation, framing and roofing are shared across the entire house.
When building a garage addition, the new structure must bear all of these structural costs. That's why many homeowners decide to turn their garage addition into a 2-story addition with living space above the garage.
How Big a Garage Do You Need?
If you're going to keep your cars or trucks in the garage, you need it wide enough to open the doors and walk around the front of the cars. The challenge when building a garage additions is our cars and trucks are much bigger.
Everyone has different ideas about the type of car/truck you should use to size your garage. Not being an expert on cars and trucks, I found this helpful table at ConsumerReports.org. You will need to identify three measurements – maximum car/truck length, width and height. Ceiling height is key for larger trucks which are much taller than the average car, affecting building height as well as the size of your garage doors (width and height).
Then you probably want to add space for a workbench and storage shelves, which are typically 2 feet deep plus you need another 2 feet to access them comfortably. You can add these on one or multiple walls, depending on how many different activities you want to use your garage for.
But wait, when you're building a new garage you have lots of options about the floor plan. When you've got the space, you can get really creative like this carriage house plan (below) from TheHousePlanShop illustrates:
- Garage doors opening on different sides of the house.
- Three separate garages (3 cars plus RV) in one building.
- Separate entrance for a tenant living above the garage.
- Workshop accessible from two of the 3 garages.
Tradeoffs When Building a Garage
We listed the decisions you have to make earlier. Here are some of the tradeoffs you can make that affect costs.
- With garage doors facing the street, a shorter driveway can access the garage.
- Town building codes may limit garage size or where you place the garage on your limit. For example, you typically have to leave the last ten feet up to the property line open. If the cost to build your garage addition elsewhere is significantly higher, you can try to get a variance showing the added cost is a hardship.
- Attached or freestanding (not attached to your home) garage addition? If the new garage can sit next to one side of your house easily (house and land), it can save on building costs when you tie into the existing wall. However homes aren't as square as you think, and especially with older houses, it can be costly to connect the new garage. With the project shown here, the older house in Newburyport MA wasn't level and floor heights sloped, so they built a room between the house and new garage which eliminated the savings you could expect from an attached garage.
Cost vs Value Report for Garage Additions
- 26 x 26 foot free standing garage addition – for two cars seems adequate for at least one SUV or truck but doesn't necessarily allow much room for storage along a side wall or the back wall where many homeowners include a workbench.
- Footings and slab-on-grade foundation.
- Framing with 2 x 4 studs and gable truss roof at 6/12 pitch, with OSB structural sheathing, all pretty standard except you can't achieve insulation standards in northern climates without 2 x 6 walls. It's also become more common to put up drywall on garage walls and ceiling, leaving the floor unfinished.
- Exterior envelope has 25 year, asphalt shingles and vinyl siding and trim.
- Garage building has 5 double-hung, vinyl windows (30 x 48 inches) and 1 exterior door (3-0/6-8 exterior door with half-glass and lock set).
- Most important when building a garage, are the overhead garage doors. The Cost vs Value survey includes 2 composite 9 x 8 foot overhead doors with motorized openers. Pick your garage door carefully for ease of operation and ya composite will require the least maintenance. Consider the cost of repairs when picking your garage and especially the opener, as my experience running a handyman business is some garage door manufacturers like Overhead Garage Door, lock you into their brand.
- Electrical service required when building a garage. The Cost vs Value survey includes a 100-amp breaker at the main house panel and 50 linear feet of trench buried conduit to feed a new electrical subpanel. There's also electrical wiring for the garage door openers, outlets, lighting inside (3-way switch for fluorescent ceiling fixtures over each bay) and outside (3-way switch for 2 exterior spotlights).
What's the Value of Building a Garage Addition?
The Cost vs Value report is a great research tool because it tells you the average cost of building a garage addition. You can review the data for the US overall, across 9 regions and if you're lucky, there's also data for 81 cities.
This report can help you set a reasonable budget for your project that will maximize how much you should recoup when you sell your home. If you do move forward building a garage addition, you can also look for ways to cut costs to increase your ability to recover more of your investment.
Building a Garage? Consider this…
The very, very first thing you need to think about if you’re considering building a garage is how long you plan to stay in your current home. A typical double detached garage project could cost you around $50,000 and might only add $30,000 to the value of your home. If you plan on staying for 5 years, that garage would cost you $4,000/year. Is it worth it? Only you can decide that. Now let’s assume you still want to add a garage to your home. Here are some books that can help you identify and prioritize your requirements.
Common Garage Addition Q&As
Can you add onto an existing garage?
Extending your existing garage is similar to putting an addition on your house. You need to follow local zoning codes, prep the ground, utilities and put up the structure, with flexibility on how to finish.
Is it cheaper to add onto an existing garage or build a new one?
Adding onto an existing garage will save material and labor costs for the fourth wall. At the same time, connecting a new structure to an old building that's not level can be costly. Talk to several contractors and get their recommendations before drawing up plans.
Do you need permission to convert a garage?
You typically need a building permit to convert a garage to make sure plumbing, electrical, HVAC and egress meets code. This will increase property taxes so for advice on resale value, talk to a realtor on what finishes will give you the best ROI.