Contractors will be visibly working on the exterior of the Capitol’s central tower through Thanksgiving. The tower work will include caulking the bronze ribbon windows, and the removal and repair of the steel windows on the 13th floor. While contractors have access they will also inspect the limestone for cracks and spalling. The joining of limestone and metal around the outside of the windows presents challenges in waterproofing. Old caulk will be removed, a backer rod installed to fill in any gaps in the seam, and then new caulk installed. With the 400 foot tower standing tall in Nebraska’s temperate climate and gusty winds, eliminating air infiltration is an important part of maintaining the efficiency of the new Heating, Ventilation and Air Conditioning system. Sealing and caulking the windows will also prevent wind driven rain from entering the building.