As visitors approach the entrance to Union Terminal they feel the sheer size of the building spreading above and around them. The half dome is the second largest in the world. But what visitors cannot easily see is how massive the rear of the building is around and behind the half dome. At over 500,000 square feet, it’s a massive undertaking for the masons, structural engineers, historic preservation architects, art conservators and chemists involved. The same work to treat steel, clean and repair limestone and reapply mortar to the joints on the front of the building is just beginning on the rear of the building. Every brick, every piece of steel, every aluminum window and door frame and finish is undergoing the same precise level of treatment on the rear of the building as it is on the front. In the coming months, you may notice fewer scaffolding and lifts in the front of the building as they slowly progress towards the rear of Union Terminal. Here’s a look at what else you can expect to see this month.
- The cleaning on the aluminum window frames on the front of Union Terminal’s half dome is nearing completion. With the windows removed for cleaning and repairs, the historic frames for the more than 1,200 windows are being cleaned using dry ice blasting. Dry ice blasting is a much gentler process than sandblasting, using the soft, mildly abrasive dry ice pellets to gently clean away dirt, grime and buildup without damaging the soft aluminum.
- Plaster is being reapplied to the ceilings of the ramps of the Cincinnati History Museum and Museum of Natural History & Science. When air handling units were removed from the CHM and MNHS roofs in March, the air diffusers in the ceilings of those areas were also removed. The holes cut to install those air diffusers in the 1980s are being patched using a multilayer plaster process that will match the original plaster.
- Neoprene anti-vibration pads are being installed under three new air handling units in the south mechanical rooms. The pads help prevent damage to the concrete it sits on. Once the pads are installed, crews will begin hooking up the air handling units to new ductwork. In total, 23 new air handling units will be installed throughout the building over the course of the project.
- Roofing repairs are beginning on the south ramp, which is now the Cincinnati History Museum, to prevent any future water penetration. The gravel on top of the roof and the insulation under it will be removed, exposing the clay tile beneath a small section at a time. Waterproofing systems will be applied before the clay tile, insulation and gravel are replaced.
- The Duke Energy Holiday Trains will be moved to their future home in what was previously the Flatboat Gallery of the Cincinnati History Museum. Although the Duke Energy Holiday Trains will not reopen until November 2018, moving them to this new gallery allows crews to make necessary mechanical upgrades in their former space. The new gallery will give guests a bird’s-eye view of the iconic trains and will have additional space for other holiday components, while being more centrally located as guests descend the escalator or elevator to the Mezzanine level just below the Rotunda.
Number to Know: 17,500 – As crews carefully disassemble parts of the exterior to treat the steel underneath, over 17,500 original bricks have been salvaged for re-use when those walls are rebuilt. Those 17,500 bricks amount to 35 pallets weighing over 39 tons.
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