12x30 Carport: Boat & RV Cover Prices, Specs & What Fits
A 12x30 carport covers 360 square feet in a long, single-width footprint. It is one of the most common sizes for covering a boat on its trailer, a pop-up or small travel trailer, or a long pickup with storage at one end. Builders often list it as a 12x31 because the roof runs a foot past the 30-foot frame. This page covers what a 12x30 costs installed, what fits, and how tall to go.
| Frame Size | 12' W x 30' L |
|---|---|
| Roof Length | 31' (overhangs the frame) |
| Covered Area | 360 sq ft |
| Leg Height | 6' standard, up to 14' |
| Vehicles | 1 vehicle |
| What Fits | Boat on a trailer, pop-up or small camper, or a truck plus storage |
| Price | From $1,795 installed |
How Big Is A 12x30 Carport?
- Frame footprint: 12' x 30' (360 sq ft)
- Roof: usually 12' x 31' on regular and boxed-eave roofs
- Standard leg height: 6', with taller legs in 1-foot steps up to 14' or more
- Framing: 14-gauge steel tubing standard, 12-gauge as an upgrade
The 12-foot width fits most boat trailers and small campers, since trailers you can tow without a special permit are generally limited to 8.5 feet wide. That leaves room to walk down both sides.
What Fits Under A 12x30 Carport?
| Vehicle Or Use | Fits In A 12x30? | Notes |
|---|---|---|
| Boat on a trailer | Most up to about 24 ft | Measure from the tongue to the back of the motor |
| Pop-up or teardrop camper | Yes | Check height with the roof or AC unit |
| Small travel trailer | Often | Many are 20 to 28 ft long; check height carefully |
| Class B camper van | Usually | Most run 19 to 24 ft and 9 to 10 ft tall |
| Class C or Class A motorhome | Often too short or too low | See the RV sizing note below |
| Long pickup plus storage | Yes | About 8 to 10 ft of spare length |
How Tall Should A 12x30 Carport Be?
Leg height is the clearance at the eave, and that is what matters when you back a trailer in. Measure the tallest point of what you are covering, including the air conditioner, antennas, a boat's T-top or bimini, or a truck's ladder rack. Then choose legs at least a foot taller.
- Boats without towers, and pop-ups: 8 to 10 ft legs
- Boats with T-tops or towers: 10 to 12 ft legs
- Travel trailers and camper vans: 12 ft legs or taller
- Motorhomes: usually 14 ft legs or taller, on a wider and longer frame
RV sizing note: Many Class C motorhomes run 11 to 12 feet tall and can be over 30 feet long, and Class A motorhomes stand as tall as 13.5 feet. For those, plan a longer, taller RV carport with 14-foot or taller legs.
How Much Does A 12x30 Metal Carport Cost?
In our September 2026 price check, an installed 12x30 regular-roof carport was advertised from $1,795 with 6-foot legs, certified for 150 mph winds and 35 psf snow, and delivered and installed in the builder's service states. Legs were available up to 14 feet in 1-foot steps.
Taller legs are the biggest price driver on a boat or RV cover, followed by roof style and sides. A vertical roof is worth considering on a long carport in snow or heavy rain, and a closed back gable or one side panel adds a lot of weather protection for little cost.
Concrete Slab And Anchors
Pour the slab to the frame: a 12x30 frame under a 31-foot roof sits on a 12' x 30' pad. Many boat and trailer owners skip the slab and anchor on compacted gravel with rebar or ground anchors instead. Ask your builder which anchors fit your site.
Do You Need A Permit For A 12x30 Carport?
Most likely. At 360 square feet, a 12x30 is well above the small-structure exemptions many local codes use. Check with your local building department about permits, setbacks and required wind and snow ratings before you order.
Compare Other Carport Sizes
For a single car or standard-bed truck, see the 12x20 carport. For a long pickup, the 12x24 carport is shorter and costs less. For two trucks plus storage, see the 24x30 carport. Every size is in the carport sizes guide.
Compare Nearby Sizes
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12x30 Carport FAQs
What Fits Under A 12x30 Carport?
Most boats on trailers up to about 24 feet overall, pop-up and small travel trailers, camper vans, or a long pickup with storage space at one end.
How Much Does A 12x30 Metal Carport Cost?
As of late September 2026, installed 12x30 regular-roof carports were advertised from $1,795 with 6-foot legs, certified for 150 mph and 35 psf. Taller legs, vertical roofs and sides add to that.
How Tall Should A 12x30 Carport Be For A Boat Or Camper?
Measure the tallest point, including any T-top, AC unit or antenna, and choose legs at least a foot taller. Boats without towers often need 8 to 10 feet, while travel trailers usually need 12 feet or more.
Is A 12x30 Carport Big Enough For An RV?
For pop-ups, small travel trailers and camper vans, often yes. Most Class C and Class A motorhomes need a longer carport with 14-foot or taller legs.
What Size Slab Do I Need For A 12x30 Carport?
A 12' x 30' slab, matching the frame. Many boat and trailer owners anchor on compacted gravel instead.