Project Description

The Rowland Institute at Harvard University in Cambridge, Massachusetts had W.S. Aiken Roofing to deliver a highly sustainable solution with Sika Sarnafil’s system to their roofing problems by installing a green roof and recycling the older existing vinyl roof. The project size is 35,000 square feet.

Having been focused on energy savings and sustainability the Rowland Institute considered a green roof solution when the Institute’s 30-yearold roof needed replacing, because it benefits the environment by reducing storm water runoff, adding insulation to the roof, improving air quality, and reducing noise pollution. In addition, since the Rowland Institute is a lab and research facility for experimental sciences such as chemistry, physics, and biology, a green roof was also a way to study the plants and growing media in vegetative roofs.

“The Institute desired an outdoor environment for conducting experiments on living plants,” said Mark Swansburg, operations manager at W.S. Aiken Roofing, Inc. of Chelsea, MA. This project was completed in April 2009.

Project Requirements

The original roof, which included 25 individual roof areas, was an IRMA (Inverted Roof Membrane Assembly) roofing system using a Sika Sarnafil membrane. When the roof reached the end of its serviceable life, the Rowland Institute looked to replace it with different roofing systems, such as EPDM, but found these systems to be more expensive.

“Plus, the original IRMA system with the Sika Sarnafil system served us well,” Bevis remarked. “We expected it to last only 15 years but it gave us 30 years of service.”

As the Rowland Institute’s long-time roofing contractor partner, Aiken was also involved in the decision to use the Sika Sarnafil system because Sika Sarnafil product has a long-standing track record and Sika Sarnafil agreed to recycle the old roofing membrane as part of their industry-first commercial single-ply membrane recycling program at no additional cost.

Since the Sarnafil® G 476 membrane that was going to be used on the new IRMA roof could also support a vegetative roof, the Rowland Institute decided this was a good opportunity to experiment with a green roof.

The section of the roof that was selected to be a green roof had originally held planters to provide a nice view to the occupants of surrounding, higher buildings. It was the institute’s version to make it a natural place to experiment with a green roof.

Sika Solutions

Inverted Roof Membrane Assembly, using Sarnafil® Peel & Stick G 476 membrane.

The multi-layers of the new roof, its numerous inaccessible overhangs and balconies, and tight location posed many challenges to the Aiken crew. The Institute’s location in bustling Cambridge meant there were limited places to set up dumpsters and staging areas. “The loading dock provided the only on-site staging area, so demolition and debris had to be carted off-site daily,” said Swansburg. “We also had to take special care in planning and scheduling the next load of materials to go up.”

Recycling the materials of the old roof, Swansburg explained, involved removing and stacking the old insulation and taking it to a recycling center, as well as preparing the old Sika Sarnafil membrane for recycling. In addition, the original stone ballast was saved and then reused on most sections of the roof.

“Recycling adds another step to the process, but it is the right thing to do,” Swansburg stated. “It also helped that the Sika Sarnafil representatives were very, very supportive in what we were doing, and were very excited to meet these eco-friendly practices.”

On the green roof section Aiken Roofing installed the Sika Sarnafil Peel & Stick membrane to a concrete deck, followed by reusable polystyrene insulation. A vegetative system was then added by Apex Green Roofs, Inc. of Somerville, MA. This included a fabric to retain water and protect the membrane, a drainage layer made of recycled plastic, another layer of fabric to keep the soil out of the drainage layer, and 3 1/2 inches of growth media and the sedum plugs. One of the biggest benefits of the Sika Sarnafil membrane is that it eliminates the need for a root barrier.

“We had a really good working arrangement with Apex,” said Swansburg. “They worked closely with the Rowland Institute to pick the different species of sedum they wanted to use, and delivered a turnkey system.” Swansburg pointed out that the soil layer was engineered for maximum absorption of up to 65 percent, thereby “protecting the highly sensitive ecology of the nearby Charles River basin.”

Sika Product

In addition the following Sika product was used in the project

  • Sarnafil® Peel & Stick G 476

Check out more information about Sika & Sarnafil roofing products in the American market

Project Participants

Roofing and waterproofing contractor: W.S. Aiken Roofing, Inc. Chelsea, Massachusetts
Green contractor: Apex Green Roofs, Inc. Somerville, Massachusetts
Sika organisation: Sika Sarnafil, A Division of Sika Corporation, USA