ONeil Building Systems

Build your dream.

From Residential & Farm to Commercial, we can build the structure for your needs.

O’Neil Building Systems specializes in custom built post-frame structures. Our team will work with you on the design, engineering, and construction of your post-frame structure.

Lack of proper storage space for your needs can lead to clutter and disorganization.

The cost of renting a space to store your large equipment, animals, belongings or other toys can add up fast. Not properly storing certain items can lead to ruined or deteriorating condition and be even more costly.

We understand your needs

You have unique requirements, vision, & wants, and we can help build your dream space for all of it. We’ve been helping other people build their dreams for over 50 years, and we can do the same for you!

One stop shop for every building need!

Whether for residential and commercial space or storage for farm equipment or even equestrian needs, we have the right fit for you.

Building Types

Do your dreams come in only one color or fit in a specific box? The answer is usually no. We approach every project the same way. We build a structure from the ground up, not using a "standard" design. If you can dream it, we can build it!


A house that looks like a barn, with connecting breezeway to three car garage and three-seasons room.

Farm & Equestrian

This is an old barn that we gave new life, by installing new roof and wall metal.


Manufacturing buildings, business offices and more.


Pool houses, park structures and more.

Pole Barn Construction in Belleville IL

The O'Neil Build Plan


Call us to discuss your needs and desires for a custom building.


We can visit the build site if requested.


We will develop our proposal and bid for the build.

What Our Customers Say

O’Neil Building Systems was easy to work with and we were very happy with the end result
NM Cheng
Google Reviews
Great customer service. Workmanship is exceptional. David knows his stuff, and it is always pleasure to work with him.
Therese Milder
Google Reviews
The product is great and their customer service is wonderful!
Julie Orlet
Google Reviews

Get the building space you need with the quality you deserve and a price you'll love.

O’Neil is a Capital Development Board approved builder. We’re an approved supplier for the state of Illinois with over 50 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 Illinois, Missouri, and parts of the Midwest.

Scroll to Top