Topping It Off

By Stanley J. Dyl II Director of Advancement & Planning  

I am excited to share that Phase Ia of the new museum facility project--structural stabilization and re-roofing of the former Quincy Mine machine shop building, on Quincy Hill, Hancock , MI --has been completed! Once the machine shop building is completely rehabilitated the A. E. Seaman Mineral Museum will relocate there.  

SmithGroup, Inc., one of the top U.S. architectural & engineering firms, designed the machine shop's new “permanent” roof system. Since the last newsletter, roof system plans were refined and streamlined, permitting final installation, which was completed this fall. The exterior roof surface consists of corrugated Galvalume metal sheathing, attached to a ventilated nail base. The ventilated nail base, in turn, consists of an outer layer of plywood over rigid insulation and air space, mounted over a substrate of felt underlayment, ½” plywood and finished wood decking. 

Water damage from leaks is one of the major threats to the long-term survival of any building--commercial or domestic, contemporary or historic. The machine shop's new roof system design takes this into account. Several flashing and lapped corrugation details in the Galvalume metal sheathing installation enhance the building envelope's protection from water infiltration. To minimize infiltration at the outer sheathing fasteners, a continuous strip of butyl tape is installed in the line of fastener pattern, to seal around the fastener as it penetrates the nail base. Similarly, the layer of felt underlayment inserted between the nail base and the ½” plywood protects the wood decking and interior spaces from water infiltration.

The machine shop's new roof system also must withstand the Keweenaw Peninsula 's legendary winter conditions, as well as the cumulative effect of seasonal climate changes. To this end, a 36” width of high temperature ice guard has been installed at the roof's gable ends and a 72” ice guard at the eaves is maintained just below the outer Galvalume sheathing, along the roof perimeter.

Climate-induced expansion and contraction of the finished sheathing is addressed in two ways. First, slotted holes are required at fastener locations, together with elongated washers and gaskets. Second, butyl tape is used along the seams of the corrugated Galvalume sheathing, between one seam and another, as well as below the corrugations along the fastener pattern. The tape will move with the fasteners and sheathing, maintaining a seal around the penetration and seam locations.

While we're celebrating the excitement of completing Phase Ia, there is still much work to do. The next major tasks are comprehensive masonry restoration and window rebuilding and installation. These project segments alone will cost between $1-2 million. This is just part of the total machine shop rehabilitation cost of $5-6 million.