KLB Construction

KLB Construction is a heavy civil and highway contractor based in Mukilteo, Washington, founded in 1984 by Kelly Lynn Bosa, a former traffic-control flagger who started the business as a women-owned company doing roadway grading, concrete and highway safety work. It remains family-run with roughly 300 employees. Its work covers underground utilities, stream and wetland mitigation, grading and retaining walls, culverts and buried structures, and roadway construction, on projects including the SR 167 expressway, the I-405 widening between Renton and Bellevue and the Federal Way Link Extension. KLB was general contractor on King County’s South County Recycling and Transfer Station in Algona, which opened in August 2026.

KLB breaks its self-performed scope into four capability groups, and each one is described in blunt operational terms rather than marketing categories. Underground utilities covers installation and repair of storm, sewer, water and conduit, wet or dry, across all market types. Stream and wetland mitigation means rerouting and rebuilding bodies of water and riparian habitat, which on a highway job is usually the permit-driven work that has to happen before or alongside the roadway itself. Grading and retaining walls covers blasting, cutting, hauling and the wall systems that hold the grading. Culverts and buried structures are built for people, fish or animals depending on the crossing.

The safety numbers are the part of this listing worth reading closely, because on public heavy-highway work they are a prequalification input rather than a talking point. KLB reports an experience modification rate of .49, inside the top eight EMRs under .60 recognised by AGC of Washington, and a six-year average EMR of .68. It has been an AGC Safety Team member for 23 consecutive years, took first place in AGC of America’s Construction Safety Excellence Award in the Heavy Highway Division, and has received Washington State workers’ compensation premium refunds through the AGC Retrospective Group Program. An annual internal safety awards meeting distributes incentive awards against those results.

The named project list runs to the region’s larger transportation programs: the SR 167 new expressway project between I-5 and SR 509, the I-405 Renton to Bellevue widening and express toll lanes, the Fall City floodplain restoration, The Hyak’s Everett riverfront, and the Goose Prairie solar project.

Staffing shows the same regional depth. The published team includes a general manager, several superintendents and eight project managers, six of whom carry PE registration. The company says many of its people have been there for decades or are second-generation employees, and that it has stayed a family company at 300 employees.