ONeil Building Systems

For O’Neil, “Building Green” means more than just creating a more environmentally friendly structure. By partnering with manufacturers who embrace using recycled materials in their processes, we can rein in rising materials costs. And by using state-of-the-art window, door, and insulating technology in our post-frame structures, O’Neil buildings deliver energy savings, increased comfort, and added value to our customers in Illinois, Missouri, and parts of the Midwest.


Our top-of-the-line, commercial quality windows from PLYCO and TEMPCO are made specifically for post-frame steel buildings. With options such as low E insulation and tinted glass, they can deliver great energy savings year round.

Insulation & Ventilation

Any of our buildings can be customized to meet your lighting, ventilation, and heating and cooling requirements. After all, more natural light means less electricity burned, and more natural ventilation means lower heating and cooling costs.

Reflective Insulation

O’Neil offers innovative insulating products from PLYCO and Guardian Building Products that are designed to reflect over 95% of infrared radiation, thereby significantly increasing the energy efficiency of your building.


Our Cupolas do more than just add a stylish cap to a building, they also increase its energy efficiency by greatly increasing ventilation. So this design option serves double duty as a performance option as well.

Durable Finishes with "Cool" Colors

With the use of “cool” colors are designed to resist the warming effects of the sun’s rays, increasing energy efficiency.

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