I like the look of individual doors. I think most single garage doors are nine feet across. You'll want at least two feet between each door, so nine times three... plus four times two... equals 35... round up to an even number and you have thirty-six feet.

My father's two car garage is 30 feet on the gable end that has the two doors and thirty-four feet deep. With all his tools, it's still very crowded.

A three door garage would probably have the doors along the side rather than a gable end. So perhaps 36 x 24 would work.

Down below, you'll need room for mowers, tools, bikes, etc. etc. Personally, I'd bump it up to 40 X 26 or 40 X 28. Those larger sizes also start to give bonus space above the garage. Bite the bullet and pay for the stronger rafters and joists that allow for storage or living space up there.

What are you keeping in the garage? 3 cars, 2 cars and a little storage, daily drives, projects that will be sitting most of the time? I think that would be a factor in my decision making.

The easiest way to figure is each garage bay is 12' x 12' with an 8 foot door.

3 garage area would be 36' x 12'.

Enjoy the journey.

eal51 in western CT

eal51,

12' x 12'? You can't fit a car in 12' deep. Perhaps a typo?
And with todays SUV's, an 8' wide door doesn't work for most people.

I also have some neighbors who did one bay with a 10' wide door so that they could get their boat trailer in.

My old rule of thumb for outbuildings: Estimate the biggest possible need, then build it 3 times bigger. It will be almost big enough! I would figure 12' of width per car as a minimum. My 2 car is 20'; you can't open a large car door next to another. Think about extra length, too, unless it's strictly for car parking.

I have to agree that 8 foot doors are too small. Good for golf carts though.

Even a chevy suburban is less than 7 feet wide (6ft8"). If you can't navigate that into an 8 foot door, you probably shouldn't be driving.

The width that Chevy gives for its Suburban is 79.1" (6'-7") and that's without it's mirrors.

Include the mirrors and it's about 7'-7" wide.
The Ford Excursion is almost 7'-8" wide.

Even with smaller vehicles, most people like a 9-ft wide garage door because it's more comfortable to pull in to.

Eight foot doors look cheap.