Largo Concrete, Inc. was formed in 1989 by post-tensioning and concrete veterans Harold (Hal) Long and Mark Carnathan. Hal is an accomplished student athlete having twice won the Big Eight conference championship in the mile and breaking the American record in the four mile relay while at the University of Kansas. He became one of the original inductees into the Post-Tensioning Institute’s Hall of Fame for his contributions to the industry prior to forming Largo Concrete. Hal is credited with the invention of the anchor which holds single strand post-tensioned cables to the slab edge, a device which is still used around the world. The Spanish translation of Hal’s last name, “Largo,” is the name of the company.

Mark Carnathan was introduced to Hal by an engineer who knew both of them. Mark had substantial experience in concrete, having worked for multiple specialty subcontractors before starting Largo Construction, a general contracting firm, with Hal. After a few years, the two realized that their extensive experience in concrete construction would be better applied as a specialty subcontractor and Largo Concrete was born.

Today, Hal has since retired from the business leaving his son Ken in place as the President of Largo. Mark and his son Phil are today the President of Northern California and Vice President, respectively. From modest beginnings as a small Bay Area contractor to a national concrete subcontracting powerhouse, Largo has continued to grow while holding true to its core values.