Annapolis, MD

Maryland State House Dome


Originally constructed in the 1770s, the Maryland State House was topped with a dome in 1794 following the building’s service as the nation’s capitol. The dome, housing the state’s legislative chambers, has been modified over the years with Neoclassical, Victorian, and Colonial Revival features. As the building approached its 250th year, the state undertook a multiphase rehabilitation project starting with the restoration of the wood-framed dome, the largest of its kind in North America. SGH provided structural and building enclosure engineering services for the project, which was scheduled to accommodate the government’s calendar.

Working with the project architect, SGH served as the structural engineer of record and building enclosure consultant. Highlights of our work include:

  • Documenting the condition of the existing dome
  • Designing structural repairs to the dome’s timber framing
  • Consulting on the replacement of the slate-shingled and flat-seam copper roofs, and repairs to cedar siding
  • Helping develop roofing, waterproofing, and flashing details to protect the dome, while preserving the historic fabric and appearance
  • Working with the mechanical engineer to understand the dome’s natural ventilation and evaluate potential condensation risks of intentional ventilation strategies
  • Designing structural repairs for the lower lantern’s deteriorated timber balustrade and detailing flashing to divert water
  • Collaborating with the contractor’s subcontractor to determine how to support the scaffolding
  • Providing construction phase services, including reviewing submittals and helping the construction team address field conditions

Project Summary



Completion Date


Construction Value
Repair & Rehabilitation | Preservation
Structures | Building Enclosures
Mesick Cohen Wilson & Baker, LLP
Specialized Capabilities
Repair & Strengthening | Preservation | Roofing & Waterproofing

Key team members

Brian Rose
Brian Rose
Senior Project Manager
Michael Zajac
Michael Zajac
Senior Project Manager