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Magnum 30x40 3-Car Garage Workshop

$15,678.00$17,420.00Save $1,742.00Free delivery and installation
Wall heightslide to set height
8'10'12'14'16'18'20'
10'

ColorsGalvalume - drag to browse

Doors & windowsQty
Gable end roll-up doors
0
Eave side roll-up doors
3
Windows
0
Walk-in doors
0
Roof style
Overhang31x41
Wall panel orientation
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Overview

Details

The perfect 3-car Garage does exist! The Magnum is a 30' x 40' Metal Building with Three 10' x 8' Roll-up Garage Doors combines 1200 sqft of space for all your vehicle, storage or shop needs. That right! 3-bay garage and 10' wide doors large enough for SUVs, full size trucks and more. Engineered and snow/wind-load certified for even the harshest weather this steel building is durable and affordable with no money down financing as low as $200/month.

Design it yourself

3D Building Design Tool

Place doors and windows, try color combinations and walk around your building before you buy.

3D metal garage design tool, rotating previewOpen the 3D Design Tool →
  1. Design Your Building

    Use our free 3D Designer to customize every detail - size, roofing, siding, colors, doors, and windows. See it built in real time and get instant pricing as you configure.

  2. Professional Review & Confirmation

    A building specialist will call to confirm details, colors, and door & window placements. Discuss low monthly payment options with financing or Rent-to-Own with no credit check.

  3. Order & Schedule Install

    No need to pay in full upfront. Secure your metal building with a small deposit. Our licensed installers deliver your building & install it to code. Most installations are completed in a day.

Included

Delivery & Installation

Free delivery and installation on metal buildings, metal garages, metal barns and carports in Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, Missouri, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and West Virginia. Your site needs to be level and accessible; we handle the rest.

Licensed and certified in every state we serve - verify our credentials for your state before you buy.

Licensing & Certifications on File

Engineer-Certified byRich Walker, P.E.License No. 61240
General Contractor LicenseLicense No. CGC1533634
Wind Load Rating150 mph, 180 mphASCE 7-22 / IBC Compliant
Snow Load RatingMin 30 psf, Max 90 psfGround snow load - ASCE 7-22
Keen's Buildings free delivery and installation service area, southeastern United States
Build sheet

Building Specifications

Size
30 x 40 ft, 10' walls
Roof
Vertical, 29-gauge steel
Framing
14-gauge galvanized steel
Anchoring
Site-specific, included
Warranty
Industry leading
Industry leading

20-Year Warranty

Every building we install is backed by a 20-year warranty against rust-through and structural defects - well beyond the 10-year terms common across the industry. Framing, panels and trim are covered; workmanship on our own installs is guaranteed for the life of the structure.

Rust-through
20 years
Structural framing
20 years
Workmanship
Lifetime, our installs
What people build

Common Usage & Applications

At 30x40 with a 12'+ wall height, this size comfortably fits the uses below - bigger crews, taller vehicles and more equipment than a standard 2-car garage allows.

RV & boat storageFits Class A motorhomes and boats up to 38' with clearance to walk around
WorkshopRoom for full-size equipment plus a dedicated bench and storage wall
Equipment barnTractors, implements and trailers under one roof with roll-up access on both ends
Commercial shop1,200 sq ft supports 2-3 bays for a small business or rental operation
Customer reviews

4.79 out of 5

1,405 reviews
★★

I was recommended this company based on another friend's experience, unfortunately mine did not go very smoothly and when things went south, after numerous phone calls and emails, this entire company threw their hands up in the air and told me to deal with it. I placed my order in November of 2025 through the Chiefland store Under Patrick. Down payment and everything went smoothly until the down payment was sent in. At this point I was told to get the foundation ready and "submit the photo's when it was ready, so that the manufacturer may get started with their part." This was completed and finalized plans were done on April 30, 2026. Like a trusting human being that someone would do their job, I waited 8 weeks. On June 16th I messaged/called for an update, no response. A week later I reach out to another branch where I've received immediate response nearly every time from Joey, only to find out there was never any submission to the manufacturer to begin progress, which Patrick D. out of Chiefland had said was done.. At this time I'm furious because I had just started my first business relying on this building to be put up in time and it turned out to now be taking an additional 8 weeks.. After numerous calls and emails to corporate, and being pushed off to the "next guy", or being told "nobody is in that can help me". When I finally got hold of the VP of the company, He told me to basically kick rocks as "I'M STILLGETTING A "QUALITY PRODUCT" and there was nothing more they can do. While the building is now assembled after delays on the doors, however the build crew left dozens of screws all over my driveway and trash all around the building. If it wasn't for Joey and the fact that I did eventually get my 30x60 building this would be a 1 star review.

Billy m · via Google
★★★★★

Huge thank you to Annie for helping me get my 30x60 workshop. She was great to work with the entire way through - honest, responsive and made sure everything went smoothly. I couldn't be happier with the building or the service.

V_Dogg · via Google
★

Disappointing **************** Keen's ******************** I contacted Keen's Buildings about purchasing a 3030 metal carport for my property in *********, **********A sales representative initially reached out and requested pictures, measurements, and information about the slope of my driveway. I took the time to gather everything requested and sent it to him.After that, communication stopped. I waited for a response but never received one, so I eventually contacted the company's main office by email to explain the situation.Shortly afterward, the representative contacted me, claimed he had already tried to reach me, and then immediately informed me that there was no way they could install a carport on my property.I understand that not every property is suitable for every company's installation methods. That's not my ************ complaint is the lack of communication and the way the situation was handled. If the installation wasn't possible, a simple explanation after reviewing my measurements would have been appreciated instead of leaving me waiting and having to chase down an answer.I was a serious customer, ready to spend several thousand dollars, and expected better customer service.Unfortunately, my experience with Keen's Buildings was disappointing.

Chris B · via BBB
★★★★★

I bought a shed from Keen’s and I’m very satisfied with the product and the whole experience from ordering to complete installation. Kudos to Shawn and Joey who provided their guidance and assistance from beginning to end!

Mario L · via Google
★★★

The process of choosing the shed and costomizing it online, Working with the sales person and getting delivery was easy. The problem was with the delivery and execution. They were aware the shed was going on a concrete. When I ordered it and spoke to the salesperson, he was aware the shed would have no four and need to be bolded down onto a concrete pad. He told me there would be no issue with that at all. He’d send the guys with everything needed to do it. The problem was with delivery and installation. I watched them drop the shed off of the flatbed… and I do mean drop, and wrecked the shed out of square. They then placed it on my pad and told me my pad was out of square. So the shed was crooked on the pad hanging over on the right rear and left front. Thankfully, they didn’t bring the right material to anchor the shed to the pad. What they brought were two 3” lond 5/8” Wide L brackets and 2 lag bolts larger than the holes on the brackets. When they left, they measured out cornered a corner diagonally on the shed and found it was over 3 1/2 inches out of square. I wound up having to boly one corner down loosely and use a 4’ prybar to force it back into square before. Putting the eight red devil anchors in to the concrete and bolting it down myself. I have to say the sheds quality is good, ordering was great and timely. Delivery was fantastic. They just need a better crew to make the delivery and installation.

Richard A · via Google
★★★★★

The sales person Wayne is great. He is easy to work with and always gives you the best price and straight with you on all the products and financing.

Jeniece V · via Google
★★★★★

Mike was EXTREMELY helpful throughout this entire journey, helping my son and I through what could have been an overwhelming experience. From beginning to end, he was there to help and guide us, answering all questions and offering excellent suggestions and advice. Loved the full "showroom" of buildings already erected (on their property) so they could be viewed and walked through, giving a real life perception of what your finished product would be like.Very professional and personable, he remembers you and makes you feel you matter. Sincere thanks for all you did for us.

Christine H · via Google
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The difference

Why Buy from Keen's

Our own crews, licensed and certifiedNo subcontractors - our own crews build every job, licensed and certified in every state we serve, with stamped engineering for permitting.
Full customizationDozens of color combinations and tailored dimensions, roof styles and features. Use our 3D design tool or speak with a building specialist.
Flexible payments & plansCash, check or credit card, rent-to-own with no credit check, $0-down financing up to $100k, and 0% APR / 12-month same-as-cash options.
Quick professional installationCustom builds delivered and installed within 1-3 weeks. Prefab metal garages are often assembled in under 8 hours. DIY kits also available.
20-year, industry-leading warrantyOur standard warranty runs well beyond the industry norm.
4.79 out of 5, 1,405 reviewsRated by customers across every state we build in.
Questions

FAQs

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Disclaimer: Additional charges may apply based on the location and configuration of doors, windows and/or roll-up doors. If the installation requires a header to properly frame the component, materials and labor for that header are not included in the price shown.

$15,678.00