The most common mistake I see with a metal carport is a width that fits the vehicle on paper and fails in real life. You can park the truck under it. You just can't open the door.
Start with doors, not the vehicle
A full-size pickup is roughly 6 1/2 to 7 feet wide with the mirrors folded in, closer to 8 feet with them out. A crew cab door swings out another 3 feet or so. Add a person getting in with a winter coat on, and a 12-foot-wide carport leaves almost nothing to spare.
Here is how I think about width:
- 12 feet: one car or a small truck, if you are careful. Tight.
- 18 feet: one full-size truck with room to walk around it, or two small cars close together.
- 20 feet: two vehicles side by side, doors can open, but not wide.
- 24 feet: two full-size trucks with space to load a toolbox or groceries.
If you drive a dually or a lifted truck, go one step wider than you think.
The part most people don't know
The clearance you get at the edge of the carport, where you actually drive in and park, is the leg height, not the peak. A roof rack, a ladder rack or a truck with a tall topper can clear the peak and still hit the eave.
Measure the tallest thing you own, including whatever you might buy later, and check it against the leg height, not the center.
RV covers are a different job
An RV cover is a carport tall and long enough for a trailer or motorhome. A fifth wheel can run 12 to 13.5 feet tall, and that is before an air conditioner or antenna. Many motorhomes are over 12 feet. For an RV cover you are looking at leg heights of 12 feet or more, so measure the real height of your rig.
Width follows from the unit. Most travel trailers and fifth wheels are 8 to 8 1/2 feet wide. A 12-foot-wide cover will shelter one, but you will brush the posts getting out. A 20-foot-wide cover gives you room to open the slides, walk around, and store gear alongside. If you have a slide-out, measure it extended, not retracted.
Length is simple: the overall length of the trailer, tongue included, plus a few feet. Don't leave the hitch out in the weather if you can help it.
What the roof and sides do for you
Most of our carports and RV covers have gables on the ends, the triangle at the top of each end. Many also have one short side panel on each side, about 3 feet down from the eaves, for shear strength. That panel doesn't enclose anything. It helps the structure resist wind. You still have an open carport, and you still need the width for doors.
If you want more protection from blowing rain or pine needles, you can add a sidewall on one side, or endwalls, and then it becomes a partially enclosed carport. Say which you want, because a wall on one side changes how you open a door.
Weather in our three states
In Bend, Sisters and the high desert, snow is the big driver. A wide carport carries more roof, so the snow rating matters more as the width goes up. In Washington east of the Cascades and southern Idaho, wind comes through hard in open country. In the Willamette Valley and western Washington it is wet pine needles and moss on the roof. An A-frame vertical roof, with panels running ridge to eave, sheds all three better than a roof where the panels run across.
Near the coast, where the air carries salt, steel choice matters. 14 gauge is our standard; 12 gauge is mostly for salt air and coastal moisture, where lighter steel rusts sooner.
Check before you order
- Measure the widest point of each vehicle, with mirrors and open slides.
- Measure the tallest point, including racks and the AC unit.
- Add door swing and walking room on the side you get in.
- Check your lot: a driveway turn, a septic field or a setback line can limit width more than you expect.
- Ask your HOA or city whether there is a height or setback limit before you pick the leg height.
A carport that fits is one you will use every day. One that is almost wide enough turns into a place to store boxes.