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 all over the Midwest.










Our top-of-the-line, commercial quality windows from PLYCO are made specifically for post-frame steel buildings. They are constructed of 100% thermalized aluminum extrusions with 3/4-inch thermo pane glazing, and with options such as low E insulation and tinted glass they also deliver great energy savings year round.

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.

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.

Our Channeldrain 2000 Siding’s enhanced performance is a product of The SpectraCote System: the most tightly quality-coordinated manufacturing and paint finishing process in the industry. Plus, these colors are designed to resist the warming effects of the sun’s rays, increasing energy efficiency:

Pebble Beige
Pewter Gray
American Red
Earth Brown
Barn Red
Slate Blue
Patina Green

Ready to take your building “off the grid?” We can outfit your structure with cutting-edge solar panel system to handle everything from heating water to generating an independent source of electricity.

  • O’Neil is a Capital Development  Board approved builder?
  • We’re an approved supplier for the  state of Illinois with over 40 years of  experience?
  • Our Engineering Department can  supply you sealed structural drawings, if needed?
  • We’ve got decades of experience  satisfying municipality requirements  and building codes throughout southern Illinois and the entire Midwest?
Still have questions? Contact Us
and we’ll be happy to give you all
the answers you need.