The 4 main things that will affect the final design of your garage are:
- Zoning and related laws
- It’s function: How you intend to use it
- Style and appearance
- The cost
Other issues might include the style you want to build it, and if you have plans to change it’s use in the future.
Laws
Even though you own your property that doesn’t mean you can use it as you please. You have to build according to what the laws allow.
The larger the city you live in the more numerous and restrictive these laws will be. If you live outside of the city in a rural area, there will be fewer if any of these building restrictions.
Zoning etc
The first thing to look at are the zoning laws, home owners associations, historic designations, flood plains, riparian areas, etc. that effect your property. They usually tell you what you can build on your property.
They will dictate where the garage can go, what size you can build, how tall you can build, and in some cases if you can build at all. And they will often dictate the color or style of the garage and how you can use it.
Uniform Building Code
These laws or regulations will dictate how to build your garage. But these are pretty uniform around the country so my instructions and blueprints will usually satisfy these codes.
But if you live in an area that has lots of moisture, snow, wind or earthquakes then your local municipality might add on additional requirements on top of these. Like engineering for snow or wind loads, or specific earthquake requirements. Wet environments will dictate building with certain types of materials.
Your local building or planning and zoning department are the place to start asking about these requirements. Once you know what you can build then you can start designing it.
Function: How you intend to use it
Size
How many vehicles will you park inside and how large are they? You will need a door for each vehicle, unless you make the garage really deep and park them end to end.
Doors dictate the width
Standard garage doors are 8ft wide for a single vehicle, or 16ft wide for 2 vehicles.
You will need a minimum of 2ft 8in between each doors and between the door and corners of the garage.
So the minimum width will depend on the number of cars you will park side by side.
- For a single car width that works out to be an 8ft door plus 2 times 2ft 8in equals 13 1/3 ft so you will round up to 14ft wide.
- For 2 cars that is a 16ft door plus 2 times 2ft 8in equals 21.33ft, rounded up to 24ft.
- For 3 cars that is an 8ft door and a 16ft door with 2ft 8in between the doors and at each end is 3 times 2ft 8in or 96 inches (8ft) plus 8ft door and 16ft door equals 32ft.
- For a 4 car garage that is 2 26ft doors with 2ft 8in in between and at each corner. 2Ft 8in times 3 is 96in (8ft) plus 2 doors (at 16 each for a total of 32) is 40ft.
These are the minimums and if you want extra storage or a place to work then you will need to add to these widths.
Depth
Most small and medium cars and short bed pickups will fit in a 20ft deep garage. Even a long bed will fit but you will not have any room to walk around either end of the vehicle.
24ft is a nice depth because it will let you park longer vehicles and comfortably walk and work around them in the front and back. Like check the oil and water or remove items from the trunk without having to open the garage door.
Height
Most vehicles will fit in a standard 7ft tall garage door. These doors need 12 inches headroom above for the door track so this is the tallest door you can fit in a standard 8ft tall wall.
If you have a taller vehicle you will need more height. An 8ft door opening will require a 9ft wall height. A 9ft door opening will require a 10ft wall height.
Unless you get into a roll up door. These often need more than 12 inches of headroom to install so check their requirements before you decide on the wall height.
Floor
The best floor is concrete because it’s strong and maintenance free. But you can park a large pickup on a wood floor if you make it sturdy enough.
If it you are building as a cabin or living quarters then a wood floor might be a better option for remote locations. A wood floor can be built above the ground and insulated.
Thickness, reinforcement
Typical concrete floor is 4in thick. But you can make it 6in of you will be putting really heavy items on. You can also reinforce it with 6in wire mesh or a mat of rebar every 2 or 3 ft. Additionally you can use stronger concrete and get fiber mesh to further prevent cracking.
Slope
Sometimes code will require a slope on the floor to allow any liquids from the vehicle to drain out the door. A slope also makes it easier to drain the water if you want to be able to wash the floor off with a hose.
Door recess
Even with a slope on the slab you might get some water running back on the floor if the rain drains poorly or blows strong onto the door.
Another option is to make a recess in the floor so the door sits 1 inch lower than the rest of the slab. This will reduce the working height of the door by 1 inch but pretty much guarantee against water backing up through the door opening.
Surface finish
You can put a smooth or rough surface on the concrete floor. Rough is safer and less slippery but smooth will stain less. But you can also cover it with an epoxy to reduce future stains.
Control joints
Concrete will need control joints every 10ft or so. You can cut them in as you are finishing the slab or you can make them the next day with a concrete saw.
The advantage of saw cutting them is that the cut is only the width of a saw blade and will not collect as much dirt and such. Plus the smaller joints will allow a creeper to roll over much easier.
Entry ramp
It’s nice to have an extra large size concrete ramp in front of the garage. This keeps dirt out of the garage and gives you some extra working area.
This ramp will need to be the width of the door and 4ft minimum length depending on the ground leading to the door.
You can always just pile up dirt in front of the door to get in, but concrete is much nicer.
Stud size
2×4 studs at 16in on center will satisfy most building codes. But 2×6 studs make an even sturdier garage and doesn’t cost much more.
If you are planning on insulating I would recommend the larger studs because you can use more insulation.
Insulation and drywall
This can be done anytime in the future. But as I mentioned 2×6 studs are a better option if you plan on insulating.
Doors, windows, skylights
You need at least 1 pass door in a convenient location. 36in wide will let you carry larger items in and out.
Windows are relatively cheap to install and they add lots of light. But they can be a weak point if you are concerned about security. A skylight is better for security purposes.
Attached or free standing
It would be nice to walk right into the garage from your house. But building codes will often dictate if this is possible or not. If it’s possible, there are a few additional things to consider.
You can’t “share” a wall with the house because it’s not designed for the extra roof weight. So you will have to build the compete wall because it has it’s own foundation.
You will also probably have to fire rate the wall and door. This means replace the existing door with one that has a fire rating that the code requires, and probably dry wall the common wall to get the required fire rating.
You will also have to make sure ahead of time what it will take to tie into the existing roof.
Security
If you need to make the garage secure then you will want fewer doors and windows and maybe add some wrought iron. Also install heaver doors and locks and maybe add an alarm and motion sensing lights.
Future usage
If you plan on converting the garage into living space in the future you will need to have sufficient electrical capacity for the additional appliances and of course water and sewer installed in the concrete. Even if it’s just stubbed in and not hooked up until you need it.
You can also frame in for future doors and windows and install the siding over top and no one will know they are there from the outside. Then when you are ready, cut them open and install the door or window. This will save you lots of future work on the retrofit.
Style and appearance
Style is more about looks rather than function. Color, shape and materials will make up the appearance of the garage. Appearance will often be dictated by your existing house and or by code or homeowners association rules.
Shape
All of my garages are rectangular because that is the easiest and most cost efficient shape to build. When you start adding corners that complicates the framing and adds to the time and materials cost.
Roof type and pitch
Gable, gambrel, flat, territorial. These are the roof types available. My plans use gable because that is the most common.
3:12 and 4:12 is the easiest to work on. But the pitch should match your existing house.
Architectural or 3 tab shingles are very common and easy to install on a minimum of 3:12 pitch. But metal is becoming more affordable. However you will probably want to match what ever is on your home now.
For low sloped and flat roofs like on a territorial you will want a hot tar built up roof. This type roof takes the proper equipment so you will have to hire a contractor for this roof.
Materials
Hardboard siding in 4x8ft sheets is the easiest material to build with. It comes in various appearances. Different thickness grooves on different widths, usually with a simulated wood appearance. You can even get it with an adobe stucco finish.
- You can install vinyl siding over OSB or plywood sheeting.
- You can add stucco over the OSB or plywood base.
- You can add a brick vineer base or corner trim.
Or some combination of these to match your existing home. My plans are based on 4×8 sheets of hard board siding. But the framing is similar regardless of how you intend to finish your garage.
Ventilation
How you vent your garage will effect it’s appearance. A large turbine vent on top is efficient when combined with some eave vents or gable end vents. If you enclose your soffits you can still vent them if you don’t want to use end vents.
Soffit
You can leave the soffits open or enclose them with siding or vinyl. Even if you enclose them you can still vent them if you like. If you leave them open you can vent them through the bird boards between the trusses.
Cost
The cheapest option is to build the garage yourself. The next cheapest option would be to build most of it and hire a contractor for the more difficult parts. Like the concrete work and maybe the roof covering.
A larger garage will cost less per square foot than a small garage. But building smaller is the easiest way to keep the cost down.
You can also spread the cost by finishing the shell then making additions at a later date. Once you have a waterproof structure you can begin using it. Install the electricity, insulation and drywall later.
It’s time consuming but easy enough to get the permits. If you hire a contractor he will usually build this into the cost estimate.