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Porta-King: 50 Years of Quality Production and Service

Since 1969 our modular in plant offices, guard booths, outdoor equipment enclosures, prefabricated mezzanines, and towers have been used for thousands of unique construction applications across North America and throughout the world. We provide our customers with cost-effective, highly functional, easy to assemble alternatives to conventional construction.

Headquartered in Earth City, Missouri, Porta-King manufactures preassembled buildings, preassembled shelters, modular enclosures, modular wall systems, structural steel mezzanines, and towers. With ten regional sales offices in the United States and two production facilities in Montgomery City, Missouri. With more than 160,000 total square feet, we have the staff, the space, and the expertise to meet your needs.

A Long-Standing Commitment to Innovation

We rarely sit still at Porta-King. We are constantly working on new ideas to improve and grow our business. This includes updates to our manufacturing processes along with product updates and design innovations to address our customers’ ever-growing list of construction applications essential to the success of their daily operation. While the company has grown over the years, our commitment to quality manufacturing and excellent customer service has never wavered.


Prefabricated buildings


Pre-framed modular wall system


Modular wall systems

Versa-King HD

Modular tall wall system

Durasteel & Durasteel PC

Prefabricated buildings

Durasteel ES

Prefabricated equipment enclosures


Structures mezzanines, observation towers, and video towers

A prefabricated guard shack being lifted by a crane from a flatbed trailer at an industrial site.

Prefabricated Construction Solutions to Address Any Application

Speed, simplicity and versatility have always been the guiding principles behind the design of the products we have introduced since our inception. Our company’s success is based simply on providing our customers with a better alternative to conventional construction materials. We accomplish this goal while never losing focus the best quality products and outstanding customer support.

While the company has grown over the years, our commitment to quality manufacturing and excellent customer service has never wavered.

At Porta-King, we take the work you do seriously, and we build structures your team can rely on. Porta-King structures are durable, versatile, and 100% customizable. Installation is more cost effective and less disruptive than anything you could build using traditional construction methods.

We strive to be the leading manufacturer of modular and portable buildings in the United States, but we can’t do that without you. Please feel free to contact us at any time for more information or with suggestions on how we can make doing business with Porta-King easier for you, our valued customer.

Steve Schulte