Raths, Raths & Johnson, Inc. (RRJ) is a national engineering, architecture, and forensics consulting firm that provides investigative, design, repair, and testing services for building structures, enclosures, and materials.

Since its inception in 1966, our staff has employed a collaborative, investigative approach that combines an in-depth knowledge of building sciences and construction materials with our testing capabilities to assess and resolve structural, architectural, and building system behavior and performance issues. Key to our technical quality and exceptional service is hands-on Principal involvement in every project.

RRJ's engineering and architectural expertise is complemented by its private testing laboratory. Prototype and component testing for investigation, design verification, and product evaluation are performed in-house or in the field with instrumentation via a comprehensive data acquisition system.

RRJ is a registered Small Business Enterprise (SBE) in the State of Illinois.

RRJ is a qualified SBE by the U.S. Small Business Administration's guidelines.