Spring has sprung in the Northwest and with it comes the familiar hum of lawnmowers and a collection of yard waste bags up and down the street as we start getting our yards and gardens in shape for the summer ahead. There are countless discussions we could have about the value of plantings and other landscaping which we will get to in future posts, but for this week we are going to talk about planting a location in our homes that is normally reserved for identifiers like “comp” or “torch-down”. I am talking about our roofs and roof-top decks; and more specifically “Green Roofs”.
In our ongoing series following the construction of Columbia City Green, we want to tell you about the green roofs they have designed into the homes and the positive contribution they make to the urban environment. While green roofs can be challenging to retrofit onto existing homes, they are easily incorporated during the design process of new homes and we hope to see their installations increase as more builders and consumers realize their value.
The term Green Roof (also known as Vegetated Roofs or Eco-Roofs) typically means plantings that are made in a growing medium installed over a buildings waterproofing membrane. There are a few different varieties; the first of which is called an “Intensive Roof”. This type of green roof is usually deeper than 8” and is planted with herbs, lawns, shrubs, vegetables, or even small trees. The next is known as an “Extensive Green Roof”. This type of Green Roof, usually 2-6” deep is planted with native grasses or Sedums and is the most common type found in residential applications.
At the Columbia City Green project Case will be installing an Extensive Green Roof that will cover approximately 200 square feet of a 300 square foot deck off the 3rd floor master bedroom. The installation in this case involves first laying down a non-PVC TPO Roof Membrane (thermoplastic polyolefin). This membrane is then covered in a layer of AmerGreen Roof Garden System drainage mat that is topped with Grower’s Design topsoil. They have substituted the Sphagnum Peat ingredient with compost as Peat is a non-renewable resource. The plantings will include drought-tolerant grasses, sedums, and other low-growing, low-maintenance plants. In this case the depth of the planting medium will be 4-8” and will be edged with the same Faswall blocks that you may remember were used for the insulated concrete foundation walls we talked about in a past post. These plantings will require very little maintenance by the homeowner (applying ¼ to ½” of compost annually) while bringing all the sights, smells, and sounds of a garden into the upper level of these fantastic homes.
However you term it or whatever you plant there the benefits of these planted areas are many. They are a storm water management solution, a natural cooling method, a filter for toxins in the atmosphere, provide a natural habitat for birds and insects, offer increased sound absorption and insulation value….The list goes on and on.
Imagine the changed landscape if the next time you looked out the window the rooftops you see now where planted and revealed colors actually found in nature. If you are putting a new roof on your house consider adding a green roof. Green Roofs block the harmful UV rays and offer impact resistance (the two leading causes of roof deterioration).
Filed under: Seattle Green Building | Tagged: Architecture + Home Design, CASE Design & Project Management, Columbia City Green, Design + Build, Faswall, Green Building, Green Homes, Green Roof, Local Communities, Seattle Green Building
[...] the Foundation, the Framing, the Radiant Heat and Ventilation, the Siding, the Windows, and the Green Roofs. We have also spoken in depth to the part these homes play in the vitality of our neighborhoods [...]
[...] a previous post we have spoken about the extensive Green Roof systems that they have installed at Columbia City Green. These green roofs are going to work in [...]