Edible Rooftop Ithaca: Capstone Project

Capstone Project – Angela: Edible Rooftop, Ithaca

Center Ithaca Rooftop GardenAs a lifelong member of the Ithaca community, I have decided to participate in the sustainable development of our recently remodeled commons area. My contribution is that of an Intensive vegetative green roof design of the Center Ithaca building located in the heart of downtown. Center Ithaca has seen a lot of change in its time and is most recognized for the size and beauty of its Atrium. The plan is to create a proposal that is attractive to the building owner as well as the businesses and residents that occupy the space, by designing a garden that begins on the roof and ends in hanging baskets for people to enjoy inside the building and out, by providing aesthetic beauty, access to fresh foods, and insulation through the winter months.

The most important component of this project was to find a way of installing a green roof as least expensively as possible. Cost is the hurdle that deters those who would have been participants in this movement from doing so. With careful planning and consideration of materials, weight, and accessibility, the lowest price can still be much higher than any. Individual might be able to economically justify, as I learned in this project. However, through donations, grants, and a CSA modeled system, one can find a more reasonable way of managing these finances.

The process:

Center Ithaca Building
Center Ithaca Building

First I looked into subsidies and grants within the state of NY, and discovered the difficulty and lack of accessibility without assistance in grant writing. This led me to investigating my options for finding professional assistance, and I found it at the Cornell Cooperative extension.

Center Ithaca Rooftop 1

I began to draw up a design to match the aerial view of center Ithaca from google maps, using an online calculator to determine the square footage of the roof. After deciding to use a hilling system for drainage, I decided that the growing medium would fluctuate between 6 to 12 inches row to row, . Using another online calculator for top soil found on Cayuga Composts website, that measures the quantity of growing medium required per cubic yard and cut that number in half to determine how much I would need total. After that, I calculated how much gravel should be used for creating the hilling system, and how much metal I would need to use as a protective cover for the rooftop by calculating the height of each mounded row, the width and length of each row, and subtracting the spaces taken up by the atrium.

Material Layers
Material Layers

The materials: 

  • Biochar, Compost and Topsoil Mix (Charged): -20 Ib/ $55/ yard
  • Peat Moss
  • Plastic bedding mess
  • Foam layer
  • Industrial kitchen matts donated
  • Limestone $50/cubic yard
  • Metal drainage plating system- scrap metal from dump $70 sq ft:
  • Recycled Industrial Kitchen Rubber Mats filled with Lime Gravel $45/cu
  • Gravel filler $35 cubic yard
  • Plastic egg carton molds
  • Irrigation piping
  • Structural support beams
  • Drip tape
Rooftop Garden Irrigation
Figure 3


Rooftop Garden Drainage
Figure 4

The irrigation system begins by the rain water entering the system through the roof level growing medium (Figure 3). As it passes through the growing medium it is directed into the  drainage pipes (in the form of gravel fed half pipes that take the water primarily to the atrium through pressurized valves at the end of each drainage row under the 6” growing medium (Figure 4). When there is excess water, the pressurized valve will shut off and send the water to the water storage tank located one of the corners of the roof through the pre existing canals. Designing the pressurized valve was the most difficult process, and involved a consultation with a structural engineering student who then went on to continue collaborating on this project for figure their own project. The rough sketch is shown in Figure 6.

Rooftop Garden Irrigation Planters
Figure 5

Another challenge I encountered was recreating the building of Center Ithaca itself in the time that I had for this project. When I finally did, I was able to more accurately determine where the planters should hang. Figure 7.  is a ground level view of Atrium 1.

Pressurized Irrigation Valve
Figure 6

The hanging planters will be attached to a pulley system running from a bar down the center of the atrium. The plants will be

View of Atrium
Figure 7

lowered as they grow assuming they are indeterminate varieties and will be hung to line up where they are most accessible for maintenance and harvest, such as balconies or residential windows.  Those that hang in the center will likely be flowers and non-fruiting vines. Figure 8 is an aerial view of Atrium 1. Inside the atrium there will be 3 foot wide beds that the water initially feeds through as depicted in Figure 5 into the inside of the atrium, through the canals shown on the left, in the grey located under the interior beds, and then through the beam beds by way of drip tape, into the hanging baskets.

Arial view of atrium
Figure 8

Initial Price Calculation:

Plant Material: $500

Growing Medium: $1,200     or:    Grow and Prepare Mix     $500

Reinforcement material: $2,000

Labor: $2,500 upfront- minimalistic/maintenance/volunteer $2,000

Additional Structures and materials: $800     – or recycled-         $350

Final Price Calculation:

To determine the price of this project, I added up the materials for the growing medium, the structural reinforcement materials, the transportation of the materials which would involve a crane lifting it after being transported to the ground level of the site and the cost of the labor from the contracting company,  and then subtracted the amount saved by recycling materials for the growing medium, drainage system, structural reinforcements, and volunteer labor. At first this number was incredibly low as shown above. However, the highest cost for installation of an intensive green roof system is the structural reinforcement, and the way one can gues the price is by whether or not the building itself was set into a concrete foundation. If it was, there is less additional reinforcement needed. Unfortunately the parking garage outside of center Ithaca just encountered structural problems despite the fact that it was set into a concrete foundation, so it has yet to be determined how this will impact the building of Center Ithaca, and could mean up to an additional $20,000.

Where this project plans to go:

As mentioned, this project intends to determine the lowest cost possible for a building to install an intensive green roof. I have already received a number of confirmed donations for from local businesses and restaurants for recycled materials. Where I would like to focus next is in getting more students involved in focused areas of the design to suit their academic goals or achievements, to add to their portfolios by giving them a chance to experiment under guidance licensed professionals. I, along with my peers, fully intend to submit this as an actual proposal come next spring to the building owner Travis Hyde, and see it through to its actual installment. This will be the final product in addition to a complete record of every step of the process made available to the public, from investigation of grant writing, to measurements and installation, to be used as an educational tool for others interested in proposing a project of their own, of any scale, to their building owners. Idealistically, this will be a great stepping stone to fuel the movement of sustainable urban development.

Check out other Capstone Projects: AidenNoahJamesSarah

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