A 30x40 Metal Building is a Great Solution for any Location

The 30x40 metal building is the 'workhorse' of the prefab kit building world, providing 1,200 square feet of column-free space. It is ideally suited for residential, farm, commercial, and outbuilding applications. All kits are manufactured to your specifications, are engineered for any location, and can be installed by a professional crew in as little as 2-3 days.

Standard 30 x 40 Steel Building Kit Package
Custom 30x40 Building with lean to
Made in USA
Solid Steel
30 Yr Warranty
Custom Engineered

Get Four Quotes

Compare prices from local suppliers and save
Get Prices

Why Choose a 30x40 Steel Building?

Versatility. Prefab building kits can easily be configured for virtually any application, from simple garages to custom modern family homes.

Durability. Rigid frame buildings are manufactured from solid steel framing and engineered to meet your local wind, snow, and seismic activity codes.

Affordability. You save on a 30 x 40 steel building compared to other methods of construction due to reduced material waste and reduced construction costs; for price/cost details, see our Steel building prices page.

A Solid Investment. Red iron buildings are permanent structures that are built to last, are warranted for up to 30 years, and add value to your property. They also require virtually no maintenance (no re-painting, replacing rotten boards, etc.)

A 30x40 metal framed building is a secure & affordable construction option that will stand the test of time in any geographical location.

  • Fast build time to occupancy
  • Economical building solution
  • DIY friendly construction
  • Custom-made to your specs
  • Near-zero maintenance
  • Easily expanded for future growth
  • Cost effective compared to wood
  • Adds value to your property

Features of a 30x40 Kit

All 30x40 building kits come fully equipped with all the necessary components for a basic structure - including primary and secondary framing, wall and roof metal panels, plus all fasteners and sealants. You then customize the base model by adjusting the roof profile and pitch and adding doors, windows, ventilation, etc., to suit your intended application and location best. Detailed below are some of the main kit features and specs.

  • Features

    Primary kit features:

    American-made, I-Beam steel framing, custom-engineered in factories across North America.

    • Customizable to suit any application
    • Designed to meet your local building codes
    • Certified to 160 mph wind & 110 (psf) snow load
    • Precision engineering for a weathertight structure
    • Red-oxide primer baked onto all components
    • Low maintenance, with 30+ year warranties
    • 100% usable, column-free space
    • Easily expanded for future growth *
    • Fast construction times
    • DIY friendly

    * if future expansion is a possible requirement, be sure to specify 'expandable end walls' when placing your order.

    I-Beam frame for a 30x40 steel building
    'I-Beam' frame for a 30x40 steel building kit
  • What's included

    All 30x40 building packages include:

    • 1:12 roof pitch (2:12-6:12 available)
    • Tapered steel I-Beams (primary framing)
    • All roof purlins & wall girts (secondary framing)
    • Two framed door openings (add extra if required)
    • Engineer stamped erection & anchor bolt plans
    • Pre-painted 26-gauge metal roof & wall panels *
    • All nuts, bolts, clips and fasteners
    • Detailed construction manual
    • Pre-drilled, numbered parts
    • Complete trim package
    • Sealants & flashing
    • Structural warranty (30-50 yrs)*
    • Paint warranty (30-40yrs)*

    *Vary by supplier

    Base kit building package
    Base kit package
  • Specifications

    30x40 building specs:

    • Wind load: 70-160 mph
    • Ground snow load: 10-110 (psf)
    • Available roof pitches: 1/2, 1, 2, 3, 4, 5 and 6:12
    • Roof styles: Gable, single slope, lean-to (LT)
    • Standard bay spacing: 20', 25' and 30'
    • Standard widths: 30' to 200' (clear span)
    • Standard heights: 10' to 40' (eave height)
    • Primary frame: I-beams (min.yield 42k psi) *
    • Second frame: purlins/girts (min.yield 55k psi) *
    • Wall & roof panels: 24 or 26 gauge metal panels

    * vary by supplier

    CAD Engineering plans
    Engineering plans for a 30 by 40 metal building
    BuildingsGuide ©
  • Exclusions

    Items not Included:

    • Delivery
    • Foundation
    • Construction
    • Insulation
    • Additional doors and windows
    • Gutters and downspouts
    • Interior finishing

    Pouring a 30x40 concrete slab foundation

Get Four Quotes

Compare & save with competing quotes from local suppliers

The Construction Process

Red iron building - build process

How much does a 30x40 metal building cost?

The average cost of a 30x40 building is $28,800 to $39,600, installed. This includes the building kit package at $15-$22/sq ft, the slab foundation at $4-$8/sq ft, and the building construction at $5-$10 per square foot. If required, doors, windows, and insulation should also be budgeted for.

For an accurate cost based on your specifications and location, apply for competing quotes from four suppliers.

ItemSquare Foot Cost
Building kit (shell)$15-$25
Slab Foundation$4-$8
Construction$5-$10
Interior Finishing$10-$100+

Common Questions

  • What roof pitches are available for 30x40 steel buildings?

    All 30 by 40 bolt-up kits come with a standard 2:12 roof pitch, although pitches ranging from a shallow 1:12 pitch to a steeper 4:12 pitch are available as an option. Some of our suppliers can provide custom roof pitches of 5:12 and 6:12.

  • How much does a 30x40 metal building with slab cost?

    On average, a 30x40 concrete lab will cost $7,200. Typically, a concrete slab will cost between $4 and $8 per square foot (based on a nationwide average) for both materials and labor. The final price will depend largely on your building location, as costs vary from coast to coast.

  • How many yards of concrete do you need for a 30x40 slab?

    The amount of concrete you need for a 30x40 slab depends on the thickness of the slab. For a standard 4-inch thick concrete slab, you will need 14.81 cubic yards of concrete; for a 6-inch thick slab, 22.22 cubic yards will be required.

    Here is the formula to calculate the amount of concrete you will need:

    Concrete needed = (length x width x thickness) / 27


    For example, to calculate the amount of concrete needed for a 30x40x4-inch slab, you would use the following formula:


    Concrete needed = (30 x 40 x 4) / 27 = 12 cubic yards


    It is always best to order a little extra concrete than you think you will need to allow for spillage etc.

  • What is a 30x40 red iron building?

    Red Iron is a term used to describe a pre-engineered steel building. Although the structures are not made from iron, they have a red finish due to the red oxide paint applied to the framing during the manufacturing process to prevent corrosion.

  • Whats the difference between a 30x40 and a 40x30 building?

    All building measurements are listed in the following order W x L x H. The main difference between a 30x40 and a 40x30 building is the orientation of the width and length.

    For a 30x40 building, the width is 30 feet, and the length is 40 feet. It is quite common to mistake the dimensions and for customers to request a 40x30 building by mistake.

    Dimensions can also be expressed as 30 feet by 40 feet; or 40 feet by 30 feet.

  • How many square feet is a 30x40 building?

    A 30x40 building has a total floor area of 1,200 square feet (sq ft). The calculation to determine this is done by multiplying the width (30 feet) by the length (40 feet) of the structure.

    For example, a 30x40 metal building would have a floor area of 1,200 square feet. This is the same as a 25x50 building, a 20x60 building, or a 15x80 building.

    1,200 square feet is a good size for a variety of uses, including an oversized garage, workshop, small warehouse, or even a small two-bedroom home. It is important to consider the needs of your specific project when choosing the size of your building.

Why choose us?

BuildingsGuide simplifies the process of finding reputable suppliers of prefab metal buildings, allowing you to select the ideal vendor for your needs and budget.

Since 2004, over 200K buyers have saved an average of 28% on their project with our multiple quote service.

Proudly serving customers in the United States & Canada for over 20 years.

Compare & save!

Let us help you find the best deal on a metal building for sale.

  • Tell us about your project
  • We match you with vetted suppliers
  • You receive four competing quotes
  • Select the most suitable supplier
  • Start your project