TORCHENGINEERING (480) 490-0064 Get a Quote

ADU Design in O'Fallon, IL

O'Fallon is the Metro East's premier suburb, anchored by Scott Air Force Base spillover and explosive residential and commercial growth along the I-64 corridor — one of Illinois' fastest-growing cities.

Get a Quote

Best price · Quotes back fast · PE stamps backed by Apex Grid Engineering

ADU plans, start to permit

Site plan, floor plans, elevations, structural design, and energy compliance — the complete drawing set your city needs to approve an accessory dwelling unit.

Designed for ADU rules

Many states now streamline ADU approvals with state-level rules on size, setbacks, and fees. We design to the current rules in your jurisdiction so nothing gets kicked back.

Fast and affordable

ADUs are small projects — they shouldn't carry big-firm fees or timelines. Lean process, best price, quotes back fast.

Project types

  • Suburban retail corridor
  • Multifamily housing
  • Medical office
  • Military-support commercial
  • Distribution

Everything else your project needs

MEP Engineering in O'Fallon

Mechanical, electrical & plumbing design — permit-ready drawings, best price.

Structural Engineering in O'Fallon

Structural design, analysis & PE stamping — permit-ready drawings, best price.

Civil Engineering in O'Fallon

Site civil & land development — permit-ready drawings, best price.

PE Stamping in O'Fallon

Licensed PE stamps on your plans — fast turnaround, best price.

Pool Engineering in O'Fallon

Pool structural, systems & permits — engineered for plan check approval.

Engineering Cost Guide in O'Fallon

Straight answers on what engineering really costs.