Since 1971, Modern Building Systems has been designing, engineering, and manufacturing factory direct commercial mobile and modular buildings for clients looking for quality and accelerated construction. Let's work together to find the right solution for your needs.

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Mobile Office Trailers

Mobile office trailers are a great option for temporary office space. They can be leased or purchased and in many cases can be set up within a matter of hours. Our portable offices can be customized to your specific needs and are available in many sizes and floor plans.

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Factory Built

Factory built buildings are prefabricated, portable and customizable structures, which can be temporary or permanent. Sections of the building called modules are built in a factory controlled environment. Once completed each module or section is transported and set in the desired location.

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About Us

Modern Building Systems has been synonymous with quality, craftsmanship, and value since its founding in 1971. We design, engineer and manufacture prefabricated commercial buildings throughout the West Coast. Our third-generation family-owned business benefits from over 48 years of continuous process improvement and finely tuned artistry. Our customer-focused mindset and attention to delivering quality products has gained the trust of over 2000 clients from a range of industries both domestically and internationally.

As one of the few factory-direct manufacturers in the modular construction industry, Modern provides significant time savings by streamlining the construction process and eliminating considerable cost by selling directly from our manufacturing facility to our customers.

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Generation Family Owned
Years In Business
Completed Projects
Awards Won to date

Our Commitment

Our mission is to provide our customers with quality and cost-effective solutions that satisfy their building needs; while maintaining profitability and the highest integrity. We set the standard for quality employee satisfaction and innovation in our industry.

Modern will be the most desired mobile and modular building supplier in our target markets by staying true to our values and providing our customers with unparalleled service through innovative systems.


We will act with honesty and integrity in our conduct with fellow employees and customers.


We will continue to develop safety standards that focus on constant improvement and individual accountability.


We will continue to develop and improve our sustainable business practices for the benefit of our community, business partners and employees.


We will meet or exceed customer expectations in everything we do.

Modern Timeline

Learn more about our history by swiping through the timeline below.


Founder, Don Rasmussen, breaks ground on December 6, 1971, and begins operations out of a small shop in Portland, OR.


The factory operations relocate to a larger facility in Tualatin, OR.


Modern joins the Modular Building Institute, an association whose mission is to expand the use of offsite construction through innovation, outreach, education, and recognition. Since joining, Modern has been the recipient of several awards and was recognized as one of the forefront leaders in off-site construction.


Modern moves to a new 32-acre property in Aumsville, OR. This facility is Modern’s current headquarters.


Don Rasmussen retires from Modern Building Systems. Ownership of the company is passed down to his two sons, Jim and Ken, who remain active in the day to day operations of the company.


To facilitate the building transportation between states, a new 124,020 sq. ft. branch is open in Pacific, WA.


Don Rasmussen was inducted into the Modular Building Institute’s Hall of Fame.


Modern continues its expansion by constructing an additional branch in West Sacramento, CA.


Modern becomes EarthWISE certified and is recognized for its environmentally friendly practices in the workspace. This certification is still held by Modern to date.


Ken Rasmussen retires from Modern. His son, Alan, and nephew, Ryan take ownership of his share of the Company.


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