This past week Marni Horwitz lectured on green roofs at the HSNY on 37th street. It was not about flashy public projects or tropical, high maintenance green walls. It was about the type of simple ligtweight, low maintenance green roof that would benefit a building - and collectively benefit the city - and what investment and benefits to realistically expect. And yes, they are still abundant in beauty.
- Roofs account for a massive amount of underutilized square footage in the city.
- Collective planting of roofs would reduce the city's 'concrete footprint' and the 'heat island effect'.
- Green roofs 'harvest' the rain and put it to use, stopping it from creating sewage overflow and carrying these pollutants to our estuaries (Bronx River, Hudson River, etc;).
- Green roofs have a thin layer that separates the vegetation and water from your roof.
- They can take a few years to become fully established; they are alive, and do need care and attention.
- Although there may be some cost savings from regulating the building temperature, the real savings may come from protecting and prolonging the life of the roof membrane.
- Planting native groundcovers provides food and a rest stop for migrating birds. They can also attract butterflies.
- If you have rooftop access an established green roof is a thing of beauty. A low-maintenance green roof can have a surprising variety of plants. Even vegetables and bulbs (like the crocuses Marni planted, above, in a new green roof planting).
At the lecture we all had a chance to help plant a small model green roof. It was very, very easy. And surprisingly lightweight, thanks in part to a special soil called Gaia Mix.
Marni's company is Alive Structures. Take a look at her website to learn more about green roofs (and walls) and see some inspiring pictures of real roofs. She also gives a free first consultation, where you can learn more about the planning, installation and maintenance process.
If you want to learn more online, you may want to take a quick look at G Sky, a Japanese company that manufactures the membranes and modular roof systems used in green roofs. They have an area that details benefits, and another page that shows what the layers of the systems look like.
matt at apartment therapy dot com