Construction Type: New Construction
Type of Contract: Lump Sum
Size of Project (SF): 21,276
Duration of Project: 14 Months
Percentage of Self-Performance: 99%

Work Performed

The Washington Adventist hospital project, The Medical Pavilion at White Oak is a six-story medical office building in Silver SPring, Maryland. Beginning in 2019, Harbor partnered with Clark Construction for the installation of the roofing system, waterproofing, vegetative roofing, and sheet metal flashing an dtrim.

The main roof level included two roofing systems. The majority of the main roof level included the installation of a vapor barrier to the concrete roof deck, the installation of multiple layers of insulation, a coverboard, and a TPO membrane roofing system. The TPO roofing system received a twenty (20) year warranty.

The remainder of the main roof level, which was planned to receive a green/vegetative roof system, consisted of a reinforced Henry 790-11 hot rubberized asphalt membrane roofing system, protection board, root barrier, and insulation in preparation for the installation of the vegetative roofing. A twenty (20) year warranty was provided for the Henry roofing system.

The green roof consisted of a drainage composite and engineered soil (media). Following proper compaction, the potted grasses and sedum mats were carefully installed along with wind erosion control mat.

The vegetation was unique in some ways as well. The green roof included the installation of potted grasses segmented from the installation of sedum mat to provide a unique aesthetic and meet the architectural demands of the owner and specifier.

Finally, Harbor installed the waterproofing at the elevtor pit(s), demonstrating our unique capabilities in both roofing, amenities, and waterproofing.

Every project has its array of on-site challenges that come into play during construction. This project just so happened to be adjoining an active hospital and another active construction site. Coordination and ground space planning was key. On the roof, intense collaboration eas required between our roofing and sheet metal mechanics for the hidden fasteners required to be installed on the face of the building in conjunction with the metal wall panels system subcontractor.

With access and space remaining a challenge, much of our sedum mat had to be loaded to the roof through the finished interior of the building.

With this being one of Harbor’s newer green roofing projects, we were forced to adapt and implement new ways to ensure that the depth of the soil was installed properly. For example, we used the installation of guide posts at twenty foot intervals to ensure the appropriate soil depth is achieved after compaction.

This project was completed on time with no injuries or incidents.


The Clark and Harbor project team worked together to deliver the customer a safely completed, high quality product…

-Mike Hurley, Clark Construction Group