Raths, Raths & Johnson, Inc. (RRJ) is an 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. Our professionals test prototypes and components in-house or in the field to investigate nonperformance, verify design performance, and evaluate products.

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.