Dennis Olson is used to dealing with large health care projects with multiple scopes of work, but the new Stanford Hospital project he’s currently working on might be the most challenging job he’s ever faced.
“I’ve never been involved with a project that’s been this complex and this difficult to roof and manage,” says Olson, the owner of Letner Roofing in Orange, Calif. “There are 16 different types of roofing and waterproofing systems, and each one is a little bit different at each location around the building.”
Located in Palo Alto, Calif., the new Stanford Hospital is an 824,000-square-foot facility that connects to the existing hospital by a bridge and tunnel. Olson is convinced his company is perfect for the job. He has been in the roofing industry for almost four decades, and he’s worked at Letner for more than 30 years. Olson worked his way up through the company as a foreman, project manager, and estimator before becoming the president and owner 15 years ago. “I have been estimating and managing health care projects for more than 25 years,” he says. “This job is right up our alley.”
Located in Orange, Calif., Letner Roofing specializes in commercial work including all types of roofing and below-grade waterproofing systems. “We are licensed with all of the major manufacturers to install their products,” Olson says. “We install basically every roofing and waterproofing system that’s available to the market. We have a sheet metal division that produces metal wall panels, roofing and general sheet metal.”
Olson believes the company’s success begins with its great alliances with top general contractors and owners. “Our strengths are our customer service and quality control, and our ability to get projects done efficiently and on time,” he says. “I think that’s why general contractors choose us. We do what we say we’re going to do, we do it efficiently, and we take a lot of pride in the finished product.”
Communication is the key, according to Olson. “We have weekly sales meetings where all of the project managers and sales staff get together,” Olson says. “We share information, which allows us to learn from our failures and successes. It’s a team atmosphere. There is no real competition between the sales guys other than the innate competition that you each have to be better. We don’t compete against each other; we all work together for the common goal.”
Keeping the lines of communication open with industry partners is a key part of the puzzle. “As far as communication with the general contractor, that’s pretty simple, but a lot of people miss that,” he says. “You have to return phone calls. You have to return emails. If you have an issue on a project, handle the issue efficiently. Bring scheduling problems or details issues to the attention of the general contractor early. Nobody like to be surprised. People like to be informed.”
Due to their expertise in design-build situations, members of the Letner team are often called in by general contractors at the design and budgeting stage to offer advice on the right materials and methods for a project.
That was the case with the new Stanford Hospital project and general contractor Clark/McCarthy—a joint venture of Clark Construction Co. and McCarthy Building Cos. “McCarthy is a contractor I’ve been dealing with for more than 25 years. I’ve done a lot of health care projects with them, so when Stanford came out, they certainly wanted our input and help developing the budgets,” notes Olson.
For Letner, the project involved several scopes of work including roofing on the main hospital and below-grade and underslab waterproofing.
Below-grade work included a pre-applied blind-side waterproofing application by Cetco. Letner also waterproofed underground tanks for domestic water, fire suppression, and sewage with a hot rubber system by Gaco Western. “The hospital was built for the worst-case scenario,” Olson notes. “If there is a big earthquake, and services are interrupted, the hospital can sustain itself for a while.”
As the superstructure was being completed, the roofing work began. “As I said, there are 16 different roofing systems on this project. There are 12 different elevations,” notes Olson.
Systems range from urethane and urethane and polymethyl methacrylate (PMMA) coatings to split-slab and inverted hot rubber systems, PVC roof systems and hybrid dual waterproofing system. The largest roofing systems include a Sarnafil PVC roof on the main hospital and a hot rubber system by Cetco for use under the garden roofs. Letner is installing garden roofs on the third floor of the main hospital and another on the central plant building.
Both of these garden roofs were constructed over flat concrete decks. The first step was to provide positive slope for drainage. “Cell-Crete provided lightweight concrete, and we used the lightweight concrete to pour slope over the flat structural concrete deck,” notes Olson. “After the concrete was sloped, we installed quarter-inch cement board over the lightweight.”
The hospital’s surgery rooms are directly beneath the garden roof on the main hospital, so the system has to be bulletproof. “This roof area requires intricate detailing along with a Cetco hybrid dual waterproofing system,” Olson states. “After the lightweight concrete and cover board are in place, Letner will install 60 mils of Hydrofix urethane membrane, followed by Cetco Corflex, a unique combination of a re-enforced KEE membrane bonded to an active polymer core membrane. Both garden roof areas will be protected with an in-place leak detection system by Internal Leak Detection.”
The overburden at the hospital garden roofs will include insulation, drainage mats, various types of plants and trees and pedestal paver systems.
Letner installed PVC roof systems from Sika Sarnafil level three of the hospital and on the main roof of the hospital. The 60-mil PVC membrane was installed over insulation and DensDeck cover board. Insulation was a minimum of R-20 near the drains. Some sections of the PVC were topped by ballast rock.
On the adjoining multi-level parking deck, Letner installed PVC roofs on two office buildings. The rest of the roofing and waterproofing work on the parking structure, including another garden roof, was completed by Courtney Waterproofing and Roofing of Irvine, Calif.
Letner and the general contractor help ensure safety is always top of mind at the site. “On this project, like any other, the safety issues were extremely important,” notes Olson. “We have our crews stretch and flex daily, and everyone must wear the personal protective equipment required for each task. Fall protection is a concern at every elevation, and hot rubber is extremely hazardous activity that requires additional protection and monitoring.”
The perimeter walls were being constructed during the project, so extra precautions had to be taken at the roof edge. “We had to wear harnesses and be tied off at all times,” Olson says. “We are very concerned about safety. We have a safety manager, and he does a very good job of identifying possible hazards on each job. We identify those per deck and apply the proper safety measures required for each elevation.”
Waterproofing the tanks also required special care. “The domestic water, waste and fire tanks and are in the ground, so you have to have people certified to do that work with specialized equipment,” Olson states.
Construction of the hospital is still underway. Work is expected to be completed in 2018. The sheer size and multiple scopes of work were obvious challenges on the project, but the schedule was also tight—and subject to change. Some roof details were changed and others were developed as the job progressed, so Letner’s crews had to make some adjustments on the fly. Letner continues to work with the consultant on the project, ABB, to iron out the details.
“Sometimes you have to adjust the schedule when you are coordinating the work with other trades,” Olson notes. “The schedule, coordinating with other trades and the number of changes on the job have been the biggest issues we’ve faced. It’s is still a challenge, as the work is ongoing.”
When it came time to stage equipment and materials, the large job site suddenly seemed small. “The site was kind of tight, so of course logistics came into play with loading and off-loading each different area,” he says. “Some areas were hard to get to, and sometimes we had to wheel the product through corridors to get to the decks. Not everything was easy to get to. Logistics were difficult, but we were able to overcome those problems. Clark/McCarthy helped out quite a bit with logistics and loading.”
Despite the complexity of the job, the installation work has gone smoothly, according to Olson. “As far as the application for our field crews, there’s not that much difficulty for them. They are all very talented at what they do,” he says. “It’s just a very difficult building, and there are a lot of details that are not typical.”
The key to overcoming difficulties? “It’s constant communication,” Olson says. “Our strengths are our management teams, from the field operations to office staff. We’re honest with our customers. They understand the level of customer service and quality we deliver. Our success is a testament to the service we provide to our customers. We are often praised for our service and workmanship, and we are very proud of our quality installations as well.”
Rafael Viñoly Architects in association with Lee, Burkhart, Liu Inc.
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Source: roofingmagazine.com =>Stanford Hospital Project Demands Versatility and Surgical Precision