HPC finds GSA seismic retrofit at Mike Mansfield Federal Building has ‘no adverse effect’ to historic district

The Butte-Silver Bow Historic Preservation Commission voted unanimously May 5 to find the General Services Administration’s Section 106 submission for the Mike Mansfield Federal Building and U.S. Courthouse consistent with “No Adverse Effect” to the National Historic Landmark District.

GSA representatives in the meeting described the project as primarily structural work to bring the building up to seismic standards while restoring historic character in public spaces. "The project is mostly structural to meet seismic standards," said Steve Janzen, who spoke for the agency. He said most work will be behind the scenes but listed exterior elements that will be repaired or restored, including spalling granite, masonry efflorescence, mortar repointing, replacement of incompatible sealants, cleaning and sealing metal grates and lampposts, terracotta restoration, and a new TPO roof deck. Janzen also said an unobtrusive ADA-accessible ramp will be added and non-original window sashes will be replaced with painted wood sashes.

HPO staff framed the proposal as a large undertaking that balances safety upgrades with preservation goals. After questions and review, Chairman Steve Hinick moved that the Section 106 review is consistent with No Adverse Effect to the NHLD; Commissioner Russell O’Leary seconded and the motion carried unanimously.

Why it matters: the federal courthouse sits within Butte-Silver Bow’s historic district; a No Adverse Effect finding clears the way for GSA to proceed with design and construction while preserving character-defining features. GSA representatives said they will continue to coordinate materials and methods with HPO staff as the design advances.

What’s next: GSA will proceed with final design and contract procurement. Commission minutes record the unanimous determination at the May 5 meeting.