It figures that someone at Harvard Business School (HBS) would know how to get the best return on its investment when it comes to roofs. That’s why HBS aimed high and replaced a small, existing green (vegetated) roof with a much larger one that would cover 11,000-square feet of a multi-tiered roof shared by McArthur Hall and the McCollumCenter in Boston. This new roof keeps the buildings watertight and grows a diverse meadow including herbs and vegetables like calendula, fennel, wild carrots and radishes — of which 400 pounds of daikon radishes were harvested and served in the school’s dining halls the first year. The team continues to experiment with other wild vegetable crops such as garlic, beets, watermelons and winter squash. 

Top view of Sarnafil EnergySmart membrane on Tree House brewery

The first task was selecting the right materials for the new roof membrane that would act as the waterproofing layer. It was decided to use the Sarnafil G 410 EnergySmart Roof Membrane, due to its track record and reputation. “The Sarnafil system is the best system you could possibly put down,” said John Marcone, vice president and project manager at Gilbert & Becker Co., Inc., of Dorchester, Massachusetts, the roofing contractor. 

view of roof on the tree house brewery

The installation of the new green roof began with removal of the existing green roof, during which Recover recycled all the growing media, saved drainage components for other projects and dug up and boxed existing plants for Harvard to use for a campus-wide plant giveaway. Then the existing EPDM roof membrane was removed, and Gilbert & Becker installed a fully adhered vapor barrier to the concrete deck, followed by some tapered insulation and a cover board. After this, the Sarnafil PVC membrane was fully adhered.

View of parking lot and roof on Tree House Brewery

Perhaps the biggest reason for the success of the project was the teamwork between all parties – including Recover, Gilbert and Becker, HBS, Lee Kennedy and Sika Roofing.“I can’t speak highly enough about the entire team,” Leonard remarked.“I was also very impressed with Recover Green Roofs. They were very knowledgeable, very accommodating and they were on schedule and on budget.” It was this professionalism that earned Recover Roof first place in the Waterproofing Category of Sika Roofing’s 2016 Project of the Year competition.


Today the roof is leak-free and producing lots of organic foods for Harvard students and faculty. “During its first year, the roof reaped 400 pounds of radishes,” Musso stated. “We are continuing to experiment with more food plants, like garlic and winter squash, and are looking forward to harvesting more food and herbs from our green roofs.”

Read the full case study of the Harvard Business School's Hall and Center. 

Has time taken a toll on your roof?

Schedule a roof quote with us and see how a green roof can be a solution for your roof.