Green Roof Assessments and Consulting Services

A green roof, by definition, is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. The history of green roofs dates back thousands of years, and green roofs can be used for protection from elements, ceremonial uses, and for agricultural purposes.

By today’s standards, the green roof has evolved over time to offer numerous benefits including:

  • Protecting roof membranes from elements and temperature fluctuations,
  • Managing storm water, and
  • Mitigating heat island effects.

Green roofs are also loosely defined to include both planted and hardscape amenity space for residential and commercial development. These benefits are supported by growing demand as more projects seek to incorporate green roof technology. Although required by local codes as an open space requirement, the addition of roof top amenity space adds value and commercial appeal for existing buildings and new construction projects seeking to retain or attract residents and commercial tenants.

Conversely, despite the many benefits of green roofs, there also exist some distinct challenges including:

  • Drainage considerations including water retention for plant growth and survival. Traditional roofs are designed to remove storm water. Green roofs require water to survive, which adds to the potential for water penetration through protective membranes. This can be caused by hydrostatic pressure forcing water into gaps and other breaches.
  • It can be extremely difficult to design and install a green roof that doesn’t leak due to various conditions, which present challenges to the waterproofing membrane performance. When this happens, it can be difficult to get back to the membrane to fix the problem.
  • The plant root systems will naturally seek out every crack, crevice, and hole they can find. Once the root is into a material, it starts pushing that material apart slowly, piece by piece, as the root keeps growing looking for water.
  • Green roofs add substantial weight to a roof system, especially in saturated conditions. This makes it difficult to design for them on new construction, requiring a heavier structure all the way to the foundation, and nearly impossible to install them on an existing building that wasn’t designed for them without significantly strengthening the structure.

Despite these constraints, implementing a successful Green Roof must be balanced with its advantages and developed with the highest possible quality assurance metrics. Pie’s Green Roof capabilities have been formed by years of industry exposure, and direct building envelope services including technical peer reviews, quality assurance field observations, and field performance verification such as electronic leak detection testing, roof wind uplift testing, etc.

Pie is fortunate to have some of the foremost roof experts on staff. As a firm of professional engineers, registered roof consultants, and roof observers, we have extensive experience working on and around green roofs.

Common services include:

  • Technical Peer Reviews of Drawings and Specifications
  • Hygrothermal Modeling – Roof and Wall Analysis (WUFI®)
  • Waterproofing Consulting and Performance Testing
  • Submittals and Shop Drawing Reviews
  • Construction Phase Quality Assurance Observations and Reporting
  • Electronic Leak Detection Testing
  • Operations and Maintenance Manuals
  • Structural Analysis, including wind load calculation
  • Designer-of-record services (waterproofing, structural strengthening, and green roofing)

Client Review

“Pie has been a trusted partner for many years and we look forward to continuing to grow our relationship with such a professional and high-class organization into the future.”

– Nick Williams, Absolute Caulking and Waterproofing, Inc.