At 21 stories high, the James A. Rhodes Tower on the campus of Cleveland State University is the second-tallest educational-purposed building in the United States. The 500,000-square-foot steel skyscraper in downtown Cleveland, Ohio houses the university’s four-floor main library, academic offices and the mechanical room.
Situated right off Lake Erie, Rhodes Tower is subjected to high wind speed and driving rain. Like many buildings constructed in the early 1970s, the CSU structure was built with precast concrete walls, which offered very little insulation or protection from moisture.
The building was plagued by leaks, especially from beneath the mechanical room’s exterior walls and the EDPM mezzanine roof. While intermediate caulking projects on the exterior panel joints attempted to stop the water that was blowing in through deteriorated areas, leaking persisted. In addition to leaking issues, several floors were abated because of environmental concerns. Rhodes Tower was in need of a major overhaul to resolve these issues.
The project involved the replacement of the 20th floor mezzanine roof system, the replacement of the 20th floor’s mechanical room exterior wall’s panels, steel siding and louvers and cleaning the tower’s precast concrete panels and a 100% sealant replacement on all four sides of the towers, from the seventh floor up to the cooling towers at the top of the building.
With the goal of sealing the tower’s concrete panels to withstand high winds and driving rain for the long-term, CSU architects tapped the expertise of Construction Resources Inc. (CRI), an established building exterior consulting firm known for high-performance, sustainable exterior restoration projects with a reputation for resolving especially challenging building envelope performance issues. CRI had successfully corrected problems on several other CSU building exteriors.
After analyzing Rhodes Tower, from the top roof systems to the library roof below, which forms the base of the tower, CRI identified the source of the leaking and determined the best solution. “Our goal was to give CSU a low-maintenance solution for the longest lifespan success with the best products available in the industry,” said Bud Griffith, CRI president and project consultant.
Many building exterior problems require integrated product application solutions; each product must work in conjunction with other products or systems so it does not become a weak link, allowing air and moisture to enter through the building envelope. For the joint sealing restoration of the exterior panels of Rhodes Tower, CRI specified a redundant system to combat the harsh weather elements and provide a longer-lifespan weather seal.
Tremco’s illmod 600 self-expanding, polyurethane foam sealant provides a watertight, vapor permeable seal that withstands wind-driven rain. The tape is driving rain-resistant up to 600 Pa, the equivalent of about a 70.9 mph wind, and its vapor permeable property ensures that moisture is not trapped inside the wall.
For Rhodes Tower, 40,000 linear feet of illmod 600 were specified for joint repair in the exterior panels. While the great height of the tower made it somewhat difficult for contractors to determine the tape size needed from the ground, illmod 600 is available in a variety of sizes, so contractors were able to mix and match the tape to fit the joints in a consistent manner. Tape rolls range from almost nine feet to 32 feet in length, depending on the width and thickness of the tape.
Once the illmod 600 had fully expanded, Spectrem 2 Silicone Sealant was applied over it to eliminate any deficiencies that could compromise the building envelope by allowing air and moisture to enter. There is no need for primer over the illmod 600 tape.
Contractors easily positioned and affixed illmod 600 to the tower’s exterior joints by pressing the pressure-sensitive adhesive side in place from one-fourth to one-half inch deep. Once the tape was positioned, the material self-expanded to fill the joints and seal small imperfections, forming a permanently elastic, weather-tight seal. There was no wait for the material to cure in cold weather, and rain wasn’t an issue because illmod 600 doesn’t need a dry surface. The time it takes for the tape to fully expand depends on the temperature: at 37°F, full expansion takes five hours; at 68°F, it takes eight minutes; and at 104°F, it fully expands in one minute.
One of these projects includes the renovation of a 173-bed, hospital. The assurance provided by the addition of this expanding foam sealant, which fills the gaps and voids and eliminates any concern over application inconsistencies, adds tremendous value to restoration joint sealing projects. The addition of the thermal and acoustical benefits is just icing on the cake.