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.

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

30x40 Metal Building Kit Features

All 30x40 metal buildings 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 along with the addition of doors, windows, ventilation, etc. to best suit your intended application and location. Detailed below are some of the main building 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 metal building
  • What's included

    All 30x40 metal 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 building package
    BuildingsGuide ©
  • Specifications

    30x40 metal 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 30x40 prefab 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
    Pouring a 30x40 concrete slab foundation

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Why Choose a 30x40 Metal Building?

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

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

Affordability. You save on a 30x40 metal building compared to other methods of construction due to reduced material waste and reduced construction costs.

A Solid Investment. Red iron buildings are permanent structures that are built to last, are warrantied 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 building is a secure & affordable building 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

The Construction Process

Red iron building - build process
Read the Build Process Guide

How do you build a 30x40 metal building?

With a 30x40 metal building kit, you get all the necessary components to construct a precision-engineered, commercial-grade structure in as little as 3-4 days. You have the choice to DIY erect the building or hire a local crew to undertake the construction. This section provides an overview of the planning, design, and construction process with links to articles for more in-depth coverage.

  • Step 1: Planning

    Planning a metal building construction project

    When considering a pre-engineered building for your home, business, or farm, you must be aware of all aspects of the construction process. From planning to execution, we'll guide you through everything you need to know to make your 30x40 metal building project successful.

    Determine Requirements

    What will you use your building for, and what are your storage requirements? The first step is to take a complete inventory of what will be stored in the new structure and ensure that it will fit in the available 1,200 sq ft.

    Decide on a Budget

    Take the time to budget for all the components of your build. This will include:

    • The 30x40 kit.
    • Additional accessories (doors, windows, skylights, etc.).
    • A 4" or 6" foundation
    • Building permit fees
    • Building erection
    • Insulation (if required).
    • Interior finishing (if required).

    Typical Installed Costs:

    • A basic 30x40 metal building with no interior finishing will cost $20-$50 per square foot, and
    • a 30x40 metal home with a full interior build-out can cost $100+ per square foot.

    Decide on a Building Height

    The intended end-use will govern the eave height of your building. The building height is measured at the eave, and there must be a two-foot clearance between the top of the doors and the eave.

    Some typical heights include:

    • Garages/shops - 10’ to 18’.
    • Barns - 12’ to 22’.
    • Single-story homes - 10’ to 14’.
    • Two-story homes - 18’ to 26’

    Please note metal frame buildings are limited to a height of 30 feet.

    Decide on the Number of Framed Openings

    The standard 30x40 kit package typically includes one framed opening for a walk door and one for a typical overhead door. You will need to decide how many more framed openings you need and how big each one needs to be. Remember that each of these will add to the cost of your building because each framed opening requires additional steel.

    Also, note that with 30 ft x 40 ft metal buildings, the center column will typically be placed halfway down the building at 20 feet, giving you two 20-foot wide bays.

    Apply for Financing (if required)

    Several options are available for financing a new building; see the planning page at the end of this section for more details). If financing is required, identify suitable lenders at this stage. You will not be able to make the loan application until you have finalized all your building details and are at the pre-construction stage.

    Apply for Building Permits (if required)

    You will almost always need a building permit, but some rural and farm properties are exempt. Once you have chosen a suitable building site for your new structure, check with your city or county building department. Note that you won't be able to apply for building and foundation permits until your chosen building supplier has received your order and provided you with the relevant engineering drawings.

    Our suppliers ensure that your building is engineered to meet your local codes for wind, snow, and seismic conditions.


    See our build process page for more details on planning a metal building construction project.



  • Step 2: Design

    Design considerations for a 30x40 metal building

    The level of design required for your 30x40 metal building will largely depend on what you intend to use the structure for. Below we briefly cover some of the main design aspects you will need to consider when customizing and configuring your new building.

    Decide on a Roof Style & Pitch

    The intended end use of your 30x40 building will largely dictate the roof profile. For example:

    • Metal homes can have a gable (traditional), single-slope (modern) monitor, or even a gambrel roof (farm or barndominium), depending on the style you are looking to achieve.
    • Garages and shops will have either a gable or single-slope roof.
    • Barns will typically have a gable, monitor, or gambrel roof style.

    Available Roof Pitches:

    • Gable - 1:12 to 4:12 (steeper pitches require special engineering).
    • Single slope (shed roof) - 1:12 or 2:12.
    • Gambrel (Dutch barn) - Upper roof 2:12-3:12 and lower roof 5:12-6:12
    • Monitor - (American barn) - Upper roof: 4:12 - 6:12land lower roof: 3:12 - 5:12

    This being said, any roof profile and pitch can be applied to your custom 30x40 metal building.

    Choose a Floor Plan (if required)

    If your building is going to be used as a home, shop house, horse barn, or dog boarding kennel, you will need to decide on a floor plan that best suits your needs and maximizes floor space. To ensure you have sufficient space:

    Step 1: Research available online floor plans and shortlist the ones you think will work best. We also have a selection of sample floor plans to get you started. You can also create basic floor plans with our floor plan maker tool.

    Step-2: Take a complete inventory of what will be stored in your new structure. Take into account your current and possible future requirements.

    Step-3: To get a sense of what will work for your specific setup, plan your layout on graph paper (using a scale of one square = 1 foot) and place/arrange scaled cutouts of your inventory, livestock, and equipment on the floor plan.

    No need to hire an architect. Our building suppliers will advise on design options to ensure you get the building you want in terms of functionality and aesthetics.

    Choose Custom Building Options

    A standard building package is sufficient for most customers, but various customization choices enable YOU to customize and configure the building to meet YOUR needs. Popular custom options include:

    Color options: Mix and match over 20 colors for siding, roofing, and wainscot to get your desired look. See our metal building colors page (follow the link to our design center at the bottom of this section) for sample color schemes and a color visualizer.

    Door options: Choose from sectional, roll-up overhead, sliding, or bi-fold doors, and pick sizes, styles, and colors that work for your setup.

    Siding options: All buildings come standard with pre-painted, 26-gauge PBR metal roofing and siding panels. Alternatively, you can add vinyl, Hardie board, stucco, or faux brick panels.

    Structural options: Customize the exterior of your building by adding any number of structural customizations, including roof overhangs, door canopies, or a lean-to.

    See our design center for additional details on configuring your 30x40 metal building.

  • Step 3: Ordering

    Get competing quotes for a 30x40 metal building kit

    Now that you have an idea of the design and style of your building let us help you get started. Tell us a little about your project, and we'll match you with FOUR vetted building suppliers who will provide competing quotes for your 30x40 kit package. Apply for quotes here.

    Once you have confirmed that you are happy with the design, a deposit (20-30%) is then required before the factory can begin manufacturing your custom building. A set of construction and foundation plans stamped by an engineer registered in your state will then be sent to you (usually in 2-3 weeks).

    Most vendors offer a full set of building plans, but some charge extra for foundation plans. Before you submit your order, be sure to confirm this with the supplier.

    With all the necessary designs in hand, you can now request estimates from a local steel building erection crew (or a general contractor) for the construction of your metal building.

    You will also be able to:

    • Approach your local building department and begin the permitting process, and
    • talk to lenders (if financing is required).
  • Step 4: Pre-Construction

    Considerations before you erect a 30x40 building

    The time between ordering your building and taking delivery will typically be around 6-8 weeks, giving you plenty of time to prep your job site. Here are the steps you will need to consider at this project stage.

    Site Preparation

    Before pouring the building's foundation, you will need to prepare the site in readiness for construction. This will include clearing and grading the site. Next, locate and map out access routes for water, gas, and other utilities. It is also essential to verify that the site can support the weight of the building by conducting a soil analysis and determining if excavation and adding road base (or similar) will be necessary.

    Run Utilities to the Job Site

    Before pouring the foundation, you will bring in plumbers and electricians to bring services to your job site.

    Plumbing professionals lay the pipes, which the foundation then covers, and the electrician will run a conduit for the power lines to run through the foundation.

    If you are using your well as your water supply, check that the current pump and pressure tank can handle the additional demand.

    Pour the Foundation

    When constructing a 30x40 metal building, a slab-on-grade foundation is typically used. This foundation provides a stable base for the building by pouring a concrete slab directly on the graded site.

    Foundation and anchor bolt plans are not typically included in the price of the building, so it is essential to consult with a local, licensed structural engineer to develop a foundation plan that meets all code requirements.

    Unless you have extensive experience installing foundations, we recommend having the foundation poured by professionals. A 4" slab will work for most end uses, but a 6" foundation will be required if heavy machinery is stored or used in your building. Another thing to consider at this stage is in-floor heating, which can be easily added during installation. Lastly, make sure that utilities are also roughed in before the pour.

    A 4" slab foundation for a 30x40 metal building will cost $4-$8 per square foot

    For more, see our metal building foundations page.

  • Step 5: Construction

    Constructing a 30x40 metal building

    When it comes to erecting a metal building, you have three main options for construction, which we cover below. Follow the link at the end of this section for additional details on the construction process.

    Prep for Delivery

    Building packages are typically ready for delivery 4-16 weeks after an order is placed. Before starting construction, be sure to have lifting equipment on hand (e.g., a backhoe or forklift) and a place to store the framing, siding, and framing packages at your job site. The final balance of payment is typically due when the building is delivered.

    Three Options for Construction

    DIY Build: You take on the entire project, including pouring the foundation, erecting the building, and finishing the interior. Steel-framed kits are designed with the DIY enthusiast in mind and come with numbered parts and complete instructions. With some construction experience and plenty of planning, a DIY build can save you 20-30% on the total project cost.

    As the foundation is a critical part of the build, we strongly recommend that you enlist a professional crew for this build stage.

    Self Build: With this option, you act as the GC for the project. You will be responsible for hiring and managing the erection crew, the foundation team, and any other subcontractors. You will also need to pull all the required permits. This option will save you the GC fees of 10-20%.

    General Contractor Build: You hire a GC to arrange and manage the erection crew and the subcontractors. This is the most costly option, but a good GC brings a wealth of experience to the project and can provide ideas you may not have thought of. This route is also by far the fastest option and one you should consider if you require a short occupancy time.

    A GC can also speed up the build time by getting permit approvals quicker due to their knowledge of the process and often due to their existing relationships with the building department and the local inspectors. GCs charge 10-20% of the project cost.

    For more details, see our page on metal building construction.

  • Step 6: Finishing

    Finishing the interior of a metal building

    The required interior finishing level will be dictated by your intended use for the building and local climatic conditions.

    Wiring Plumbing & Finishing

    When you buy a building from one of our suppliers, you only buy the building shell. This includes all steel framing, metal roofing, and siding panels. In addition, you will need to hire local subcontractors to handle the wiring, lighting, heating, plumbing, flooring, and any internal framing that needs to be done.

    Add the Insulation

    Building insulation is a worthwhile investment that can save you money on energy costs year-round. It helps keep your building cooler in the summer and warmer in the winter, prevents condensation, and provides soundproofing. Fiberglass blanket and spray foam insulation are the most popular options for energy efficiency. You can either purchase these materials from your building supplier or source them locally.

    For more, see our metal building insulation page.

    Interior Framing

    Again, this will depend on your intended use for the building. But if interior rooms or a second level is required, you will need to hire a local framing company for this project stage.

    Most metal buildings are single wide-open spaces. Optionally, the building can be split into multiple sections to accommodate an office, a bathroom, a storage area, or a mezzanine loft level.

    Walkthrough and Final Inspection

    To ensure that your building project is completed correctly and per local building codes, it is essential to have formal inspections carried out at various stages throughout construction. A final inspection will be required at completion to complete your permit process. Once you have passed your final inspection, you will be provided with a certificate of occupancy by the building inspector.

How much does a 30x40 metal building cost?

The average cost of a 30x40 metal building is $28,800 to $39,600, installed. This includes the building kit package at $15-$22/sq ft, the 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
Interior Finishing$10-$100+

Common Questions

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

    All 30x40 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 are able to provide custom roof pitches of 5:12 and 6:12.

    For more details see the 'roof pitch' section on our roofing page.

  • How much does a 30x40 concrete 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?

    For a standard 4" concrete slab, you will need 14.81 cubic yards of concrete; for a 6" slab, 22.22 cubic yards will be required.

  • What is a 30x40 red iron building?

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

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