30x40 Garage

An oversized 30x40 garage offers a generous 1,200 sq ft of usable, column-free space that will comfortably shelter 3-4 cars and still offer plenty of work or project space. Or, for storage purposes, you could squeeze in up to 6 cars (depending on door configuration).

Start by letting us know about your access requirements, and our suppliers will assist you in designing an ideal layout. Apply for multiple quotes.

Detached Three Car Garage
Three Car 30x40 Garage
BuildingsGuide ©
1,200 sq. ft.
1-6 Cars
Solid Steel
Made in USA

Sample Garage Designs & Layouts

Below are examples of some of the most popular 30x40 garage designs, showing various door configurations for typical setups.

Please note:  sample designs and layouts are for inspirational purposes, as all kits are custom-made for your specific requirements.

Standard 30x40 Garage

Basic design for up to six vehicles

Large 30x40 prefab garage for six vehicles

A standard metal garage building will comfortably house three cars and provide over 400 square feet of storage or workspace. You could max out at six cars or four full-sized trucks with an additional overhead door. This configuration also benefits from five 4x3 windows and two entrance doors, providing easy access via the front and side of the structure.

Layout & Specs

Layout for prefabricated 30x40 garage with stalls for 3 to 4 vehicles
Roof style/pitchGable, 2:12
Overhead doorsOne 12x10
Entry doorsTwo 3x7
WindowsFive 4x3
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Drive Through Garage

Pull through configuration for boats & trailers

Pull through 30x40 garage for boat & trailer storage
This 'drive-through' design allows you to drive a boat or trailer through without the need to unhitch or reverse out. It will accommodate a typical truck towing a boat or trailer up to 17' in length. You will also benefit from an additional 250 sq ft of storage space along each side of the structure. Plenty of natural light is provided by six 4x3 windows, and a side entrance door is included.

Layout & Specs

Large pull-through 30x40 garage floor plan
Roof style/pitchGable, 4:12
Overhead doorsTwo 12x12
Entry doorsOne 3x7
WindowsSix 4x3
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Three Car Metal Garage

Large garage with 2 bays and 3 parking stalls

Oversized 3 Car Metal Garage
The three-car configuration accommodates two cars behind the double-wide door and a further car or truck behind the single OH door on the right-hand side. This floor plan also benefits you with an additional 300+ sq ft of storage space or project space.

Layout & Specs

Floor plan for large 3 car garage
Roof style/pitchGable, 4:12
Overhead doorsOne 16x10, one 12x10
Entry doorsOne 3x7
WindowsSeven 4x3
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Large Garage with Carport

Garage with additional lean-to storage

Oversize garage with lean to carport
The 'lean-to' garage will comfortably shelter 2-4 vehicles behind the two 10x12 doors. An attached carport on the front side wall offers a further 400 sq ft of covered space for equipment, vehicle storage or parking. Six 4x3 windows and a service door are also included.

Layout & Specs

Floor plan for 4 car garage with lean-to carport parking
Roof style/pitchGable, 4:12
Overhead doorsTwo 10x12
Entry doorsOne 3x7
WindowsSix 4x3
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The 3-Bay, 3-Car Design

Large three bay garage

3 bay steel garage
Another 3-car option is the 3-bay configuration. This configuration is a slightly more expensive option than the 2-bay because a portal frame has to be used to accommodate the three garage doors. This example layout has two 10x10 doors for regular vehicles and one 12x10 door for wider trucks, trailers, and boats.

Layout & Specs

three bay - three vehicle parking structure layout
Roof style/pitchGable, 4:12
Overhead doorsThree 10x10
Entry doorsOne 3070
WindowsSeven 6x3
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Installed kits from: $25 - $50 Per Sq Ft

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Similar Sizes

30x50 drive through garage design

30x50 Garage

With a 30' x 50' garage, you get 1,500 sq ft of usable, clear-span space that can be designed as a comfortable 4 car garage with 500 sq ft of bonus space or adjust the layout for use as a drive through garage for boats and trailers. Or, for longer-term purposes, you can securely store up to nine vehicles. View our collection of custom garage buildings.

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40x60 garage with lean to in forrest green and light grey

40x60 Garage (6 to 12 cars)

A 40x60 garage is one of the most versatile garaging solutions available if you need an oversized garage. At 2,400 square feet, this garage makes a great 6-car garage with an additional 900 sq ft of storage or workspace. Or, for long-term vehicle storage, you can house a maximum of twelve regular-sized vehicles. Also, consider adding a lean-to carport for additional covered parking space or partition off part of the interior and add office space and a bathroom. See our sample designs and layouts.

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Common Questions

  • How many cars fit in a 30 x 40 garage?

    A 30x40 steel building will comfortably shelter four cars or trucks. If you intend to use your garage daily, we recommend installing doors at each end of the structure for easy access. Alternatively, if it's for vehicle storage purposes, you could squeeze in 8 cars or 6 full-size SUVs.

  • How thick should a concrete slab be?

    Typical steel frame garages require a 4" floating foundation. If you are storing heavy commercial equipment or installing car lifts, then a 6" foundation will be required.

  • What size doors do I need?

    For cars and trucks you will need an 8x8 door as a minimum; consider adding a 10x8 to give you more room when backing in. If you need a double door this would need to be 16x8. For box trailers or boat storage, you will want to consider either 10' or 12' high doors to allow adequate clearance.

  • Can I source and add my own doors?

    Yes, our suppliers are happy to quote for your new building, either with or without doors. Ask for a quote with doors. That way, you can compare with doors you can source locally.

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