Team Approach Leads to Significant Cost Savings for Texas Children''s Hospital
Texas Children’s Hospital, located in Houston’s Texas Medical Center, is one of the largest pediatric hospitals in the United States. The hospital has garnered widespread recognition for its expertise and breakthrough developments in the treatment of pediatric cancer, diabetes, asthma, HIV, premature babies, and cardiogenic and attention-related disorders. The entire campus in the
The low-rise roofs of the West Tower were built in 1990 and totaled approximately 55,000 sq. ft. on several different levels. Six years later these roofs served as the construction platform for the 15-story high-rise portion of the tower. By 2004, the combination of the stress from the previous construction project and the high levels of rooftop traffic that is normal to any hospital took their toll, and the roofs began to leak above some highly sensitive spaces within the building.
In July of 2004, a water leak was discovered over a critical area in the Neonatal ICU. Having maintained the roof systems for several other buildings within Texas Children’s Hospital complex over the last five years, general contractor W.S. Bellows Construction Corporation contacted Chamberlin’s Ed LaMont to investigate the leak source. LaMont dispatched technicians to take a sample core of the roof around the leak area and ascertain the condition of the surrounding insulation. “Immediately it was discovered that the roof was totally saturated,” said LaMont, “and was literally floating above the structural concrete deck.” With the severity of the situation in mind, LaMont suggested that a roof consultant be brought in to perform more roof cores throughout the entire roof area to verify the amount of moisture present in the roofing system and the concrete deck.
“After an initial assessment of the roof using infrared thermography,” said Robert Dulovics, Senior Roofing Consultant of Raba-Kistner Consultants, Inc., “it was found that large quantities of the existing Lightweight Insulating Concrete (LWC) decking was very wet.”
Removal and replacement of this material was going to be extremely costly and disruptive to the ongoing operation of the facility. However, testing of the LWC at Raba-Kistner’s Houston materials laboratory indicated that if the LWC could be dried, then it would have the structural integrity to continue to serve as the support for a new roof. With this discovery, an innovative plan was designed to dry the deck. But first, the roofing system on top of the saturated areas had to be removed and a temporary one put in its place.
Chamberlin removed 9,000 sq. ft. of the existing roof membrane down to the wet LWC deck. A drying system consisting of powered fans and make-up air intakes was installed and allowed to run for the duration of the project. “This negative pressure drying system was designed to bring the moisture content of the LWC back to a level acceptable to the roofing manufacturer for issuance of their premium warranty,” said Dulovics. This procedure saved Texas Children’s Hospital as much as $250,000 when compared to what removal and replacement of the LWC would have cost.
To seal the building and protect it from further water damage while the deck dried, Chamberlin fastened a modified bitumen base sheet to the deck and then covered it with a temporary 80-mill Firestone glass-base sheet.
Soon after the temporary roof was installed the Chamberlin roofing team removed the remaining 46,000 sq. ft. roofing system. Roof locations were varied in size and on multiple levels. “This made the removal of the roofing debris and the installation of the new roof a logistical challenge,” said Chamberlin Operations Manager Bill Lawson. “All areas had to be well planned in advance to ensure that the removal and replacement was done in a manner that would not interfere with the hospital’s daily activities.”
The crew worked nights to mobilize the roofing materials needed for the project so as not to impede the daily routine of ambulances, employees and patients. The roofing membrane was installed with Firestone cold adhesive, rather than hot tar, to alleviate the risk of exposing patients with respiratory problems to the strong odor. In addition to the roof installation, all pitch pans and counter flashings were replaced with new stainless steel flashings.
In April after four months of drying the concrete deck Chamberlin began removing the temporary roof system and installing the permanent one. Keeping the interior of the building dry during the re-roofing process was essential. “This was important since the Neonatal ICU was beneath the temporary roof areas,” Mike Alexson, Chamberlin Roofing Superintendent stated, “so, naturally, our end-of-the-day tie-ins were a high priority.”
Texas Children’s Hospital facilities representatives praised the team for completing this logistically difficult project without any major disruption to hospital operations and within the budget available. “Chamberlin did a fine job of keeping the work rolling despite the access restrictions,” noted Tony Mansoorian, Project Engineer with W.S. Bellows Construction Corporation. “They were able to re-roof an occupied hospital with no disruption to day-to-day operations and minimal odor complaints from staff members and patients.”
Lawson commended his roofing team, “Mike Alexson, Calvin Butler and the entire crew did a tremendous job scheduling and communicating with W.S. Bellows and Texas Children’s Hospital. They successfully followed through with the plan set in place and got the job done right.”