Roofing Design: Process considerations for smoother installations

Roofing crew tearing up concrete, existing roof material, and ballasted ethylene propylene diene monomer (EPDM) membrane from a commercial roof.

The most important element to consider when determining the schedule of a roof install is the expectations of the customer. It is important to set realistic expectations on the front end of the discussions in order to avoid miscommunication and confusion during the installation.

It is critical to set a realistic deadline that works for both the installer and the customer. If uncontrollable factors arise during the process, it is important to keep the lines of communication open with the customer. Setting specific work schedules and meeting agreed-upon deadlines is crucial to a smooth installation.

Special considerations
Other special considerations may need to be worked out and understood before the project begins. For example, if the building for which the roof installation is scheduled has dock doors, it is important to remember they allow wind to enter the building, creating a positive pressure underneath the roof deck. A specific fastening pattern design is required to ensure the roof maintains attachment when the doors are open.

Case study
Located in St. Louis, Missouri, the Washington University School of Medicine is consistently ranked among the top 10 medical schools in the country. The school’s faculty physicians see patients at Barnes-Jewish Hospital and St. Louis Children’s Hospital.

The medical campus was founded in 1891, since expanding to cover nearly 17 city blocks (approximately 66 ha [164 acres]). It is home to several buildings housing laboratories for research, including the Clinical Sciences Research Building, which was constructed in the mid-1980s. In the late 1990s, the school had outgrown the original research building and needed to expand. The faculty and staff decided to expand the facilities and build the North Tower Addition. The addition currently includes laboratory space where scientists in anesthesiology, immunobiology, and cardiovascular research carry out their work.

In order to ensure the faculty’s continued operation in the laboratories and research facilities, the cooling tower roof on the North Tower Addition needed to be fixed. RSS Roofing Services & Solutions was hired to complete the reroofing process. During the renovation, approximately 372 m2 (4000 sf) of concrete pavers, roof membrane, and saturated tapered insulation were removed to expose the structure’s concrete deck. As many of these roof items would be reused, the contractor was responsible for field-verifying reusable components and properly disposing of damaged ones.

After removing the existing roofing materials, new tapered insulation (80-mil) and polyvinyl chloride (PVC) white membrane were installed, along with the existing concrete pavers. After the workers reinstalled the concrete pavers, there was still an issue involving water pooling on the roof in various areas. To fix this issue, a new roof drain was installed. The workers noticed an important stumbling block when first assessing how the job on the North Tower Addition would be completed—getting the materials to the roof would prove to be a challenge because access to the 12th-floor cooling tower was limited. Therefore, all material was brought in carts through the loading dock, up an elevator, and through a penthouse door.

Dealing with waste materials is always an issue when handling a roofing job of any size. Workers needed to ensure all waste materials were transported out of the building in large wheeled bins—similar to the way they had originally taken the materials to the roof.

The roofing system, which carries a 20-year warranty, is performing well and protecting the research facility. The roof and sheet metal labor hours totaled 1643 and included working Monday through Saturday. Thanks to the dedication of the five-man team, the project was completed on budget and within one month.

Many of the approaches to a new or renovated roofing installation are determined by parties other than the designer. Commercial roofing contractors have significant and exclusive understanding of the varying factors design professionals should consider for a seamless installation, which can affect the project’s outcome. These considerations include building usage, climate, efficiency, system specifications, access, and scheduling.

It is critical roofing contractors, designers, and other project team members collaborate with the building owner throughout the entire process to successfully and smoothly install a long-lasting roofing system.

Ted Kinsella is a senior project manager for RSS Roofing Services and Solutions, a design-build roofing contractor covering projects of all sizes for the commercial, industrial, and institutional markets. He has more than three decades of roofing industry experience. A member of both the International Facilities Management Association (IFMA) and the St. Louis Council of Construction Consumers (SLCCC), Kinsella is a past member of the American Subcontractor Association (ASA).He can be reached at

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