McMahon Steel Company, Inc. was founded in 1970 by John J. McMahon, who emigrated from Dublin, Ireland to San Diego in 1968 where he originally found employment in the ship yards of San Diego.  In 1970, he established C & B Steel, Inc., operating out of a small yard in National City.  Later, in 1979, John developed a facility in Chula Vista, CA, where he progressed and developed the structural side of the business.  The family owned company was renamed McMahon Steel Company, Inc. in 2000, when the firm’s operations were passed on to the second generation of family owners, including John’s two son’s Derek and Kevin McMahon.  Over the past 49 years, McMahon Steel has served the greater Southwest region and have successfully completed over 1,200 projects in our company history.


Our company mission is to build the highest quality steel structures while also providing the highest level of performance through on-time delivery and completion, competitive pricing, exceptional service, specialized knowledge, and industry-exceeding safety standards. Our company business philosophy is to provide bold vision, a “can-do” attitude, and excellence in all areas of endeavor, including:

  • Quality of Work
  • Customer Relationships
  • Accountability
  • Commitment to Deadlines
  • Safety
  • Environmental Responsibility

Our performance is proof of our promise to you, our customer.