Marshall County Courthouse

Marshalltown, Iowa

On Thursday, July 19, 2018 an EF-3 with a recorded 144 mph wind tornado hit the center of Marshalltown, Iowa leaving a path of destruction. The 1886-Marshall County Courthouse was one of the buildings damaged by this storm. The force of the tornado twisted the dome and bent the spire from its place at the courthouse pinnacle.

Following the storm, OPN was hired to provide a conditions report. The initial evaluation included a review of code issues, building loss, structural damage, subsequent water damage to the building interior and site elements damaged or destroyed.

A 3D building scan revealed a detailed and nuanced view of the damage, including twisting and deformations not perceivable through visual inspection. The existing wood dome structure and sheathing had been twisted and damaged beyond repair. The original wooden structure and skin of the dome was determined to be damaged beyond salvage. This provided a unique opportunity to replace the existing historic dome with one that would last for another 150 years.

The new dome is constructed of steel with new ladders to provide the county adequate access for inspection and maintenance. The steel structure will be clad with a two-part custom rain-screen with Bermuda-style lapped copper to match the angles and profiles of the damaged historic dome. The copper panels will be removable to allow for replacement as required. The spire that was removed during the storm will be rebuilt to match the original, and topped with a new weathervane, using the original construction drawings and drawings from the 1970’s for reference. The architectural detail elements will once again be made of fiberglass to replace those from 1977. In addition to the work on the dome and spire, the restoration will include the clock tower, gutters, roofs, and replacement for seven of the eight limestone chimneys. New exterior building lighting, trees, and interior renovations to repair water damage and address code issues.

Pre-tornado, OPN Architects completed a study of the current use of County owned and leased facilities including the space utilization of the current Marshall County Courthouse. The study included the re-programming of existing facilities and departments, structural and field verification and analysis, option test fits of various facilities cost options, and summary reports.

Explorations included opportunities to eliminate County leased space for various departments, find efficiencies within the department, for the expansion of County Government and the growing needs of adequate juvenile and juried courtroom space within the Courthouse. Creating secure checkpoints to the County Judicial and District Attorney Office was also a priority. In addition to the Master Planning effort, OPN planned for future infrastructure maintenance and construction for the Courthouse, including new windows and doors and estimated costs associated to those projects.

The findings of this space study formed the foundation of interior renovations at the courthouse concurrent with the exterior rebuilding.

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