Construction Capabilities

W.J. O’Neil Company specializes in industrial and commercial installations and service. Through acquisition and growth, we have expanded into a multi-faceted mechanical contracting company serving clients throughout North America and Mexico. Our expertise covers a wide range of in-house capabilities, including:


Controls Division

The WJO Controls Division is integral to our full-service mechanical contractor capabilities providing essential support to our construction group. The state-of-the-art web-based energy management systems that the Controls Group delivers greater efficiency with instantaneous information that is easy to access.

Design/Build Services

Whether you need a complete proposal based on your pre-designed plans, or a team construction project, we can deliver value on your investment. Every one of our clients — large or small — gets the same superlative customer service. When WJO is your single source of responsibility, you maximize cost-effectiveness, quality craftsmanship and on-site safety.

Building Information Modeling (BIM)

Building Information Modeling (BIM) is changing the way buildings are designed, constructed, and operated, and W.J. O’Neil is at the forefront of the technology. Our 3D CAD Design and layout capabilities allow us to engineer new products, estimate material layouts, and check for possible design conflicts before starting a new job.

We fully support the BIM process, and our capital investment in software, hardware, and personnel maintains our leadership in this evolving technology. We incorporate this model into our everyday work and our clients realize the savings in cost and time.

Pipe Fabrication

With two strategically located fabricating facilities, W.J. O’Neil Company has the logistical advantage to serve the needs of clients everywhere. Our fab shop in Livonia, Michigan and our new fabricating facility in Chattanooga, Tennessee enable us to produce any pipe fabrication offsite so costs, schedules and engineering are controlled, and safety and quality are maximized.

WJO has certification in all of North America. Our ASME “P” stamp covers work in the United States, and our TSSA Certification is for product shipped to Canada. Our certified personnel specialize in unique welding procedures, including Heliarc, TIG, MIG, submerged arc, shielded metal arc and orbital.

Both facilities feature state-of-the-art equipment and technology. Work is performed by local pipefitters and plumbers, trained to current standards and certified in most welding standards including orbital welding.


WJO provides a full range of plumbing capabilities. In our large, innovative fabricating facilities, our expert staff can fabricate offsite plumbing components for specialized projects. Our broad capabilities give you single-source accountability. Plus, they allow us to seamlessly integrate plumbing into the functionality of a client’s building project, including our other systems such as HVAC, process piping, mechanical systems, and controls.

Process Piping

W.J. O’Neil Company is recognized nationally for our Process Piping Division. Two large fabricating facilities in Michigan and Tennessee support our field installations, so costs are controlled and safety is maximized. The key to our success is our methodical preproduction process. We collaborate directly with building owners and the other trades to ensure all processes are coordinated and piping systems are fully integrated with the building’s overall mechanical systems.

Our veteran staff relishes the challenge of demanding assignments. Past WJO projects include refineries, automotive assemblies, chemical plants, utilities mains and our area of expertise, paint systems.

HVAC Installation

W.J. O’Neil has years of experience installing both commercial and industrial HVAC systems and we bring a wide range of expertise to every worksite. Our project planning and management are first class, so you can be certain your HVAC system is right-sized to your facility. You get a system engineered to run efficiently and save you money.

Additional Services Offered

W.J. O’Neil offers additional expertise in the following areas:

  • Systems Analysis
  • Survey, Testing and Solutions
  • Sheet Metal Duct and Exhaust Systems
  • Refrigerants (All Types, including Ammonia, Recovery and Recycle)
  • Data Centers (Precision, Environmental and Main Frame Chillers)
  • Indoor Air Quality Clean Air Systems
  • Piping (Refrigeration, Steam, Air, Water and Process)
  • Balancing (Air and Hydronic)
  • Plumbing (Backflow Certification)
  • Chillers (Centrifugal, Absorption, Reciprocating, Screw and Scroll)