If you are planning to build a double carport, you will of course need to figure out how much space you need in order to build your structure. I have done some research into the common sizes for a double carport for those of you needing to store more than one vehicle.
In order to house two vehicles comfortably, you first need to decide whether you require a building which is over sized, so that you can accommodate larger vehicles such as pickups, vans or even a motor home, or whether you require a building on the smaller end of the scale, to accommodate small economy cars or ATVs and motorbikes.
Let’s start with the standard size for a single carport – 10×20 or 12×24 feet are the two most common sizes for single carports. The larger size is convenient if you have wide swinging doors, or tend to drive larger vehicles like vans or pickup trucks. Some people have said that the smaller size really is too small – there is very little extra front to back room, and it is too tight for cars with long doors.
So a double carport standard size is about double the width of a single carport. 24×24′ makes a nice size carport, although you could get away with a bit narrower, since you probably won’t be opening both vehicle doors at the same time.
If you drive larger vehicles, or are planning to store even larger equipment, such as a boat and an RV, a double-width carport will still suit your purposes, but you will need to increase the size of your carport appropriately so that the larger vehicles can be properly stowed with enough clearance room around each vehicle to make getting in and getting out convenient.
The height of your double carport will also be dependent on the type of vehicles you need to store. Typical carport height is either 8 or 10 feet, although if you own trucks, vans or motor-homes you will probably want to go with a 12′ ceiling (remember that is the inside height, your peak will be higher). If you are storing an RV, remember to add extra height for any roof appliances, such as fans, satellite TV receivers or air conditioning units.