Living Roofs: An Old Idea Made New

Image courtesy of Evgeni Dinev/FreeDigitalPhotos.net

Have you ever noticed how old-fashioned ideas find their way back into modern life?  One example of this is the living roof.

Several years ago my children and I visited a pioneer village in northern Utah.  They had a pioneer home from the 1800s that was built mostly underground with a sod walls and a sod roof.  Although we were over-heated from the July desert sun, when we stepped inside the home we were amazed at how cool the interior temperature was without any air conditioning.  In frontier design, the sod house, or "soddy" was a way for pioneers to build shelter when timber or masonry was limited. 

Today, sustainable designers have incorporated ideas from the soddy into modern design.   One of the goals of sustainable design is to reduce our need to use electrical or natural gas resources from the grid.  Environmental designers know that although the surface temperature of the earth absorbs and loses heat, four feet under the earth's surface maintains a constant temperature of about 58 degrees -- or the average temperature for your location.  (For those who have basements, just think of how much cooler they are in the summer than the top levels of your home.)  When building four feet into the earth, both the pioneer and modern builders are able to tap into the stable temperature of the earth.  Further, the sod roof would act as insulation -- keeping the cool temperatures in the home during the summer and keeping the heat in during the winter.

As you may know, my husband and I are soon to be the proud parents to four chicks.  Chickens are sensitive to extremes in temperatures.  There can be some risks associated with different methods of heating and cooling the coop for the chickens.  In the summer, cooling systems that add humidity (such as misters used in the desert spas) can cause respiratory problems.  And many heat sources can cause possible fire hazards.  So, although we will be researching safe modern methods of climate control for our chickens, we also want to incorporate some green design.

We began by noting the placement of the hen's house.  We picked breeds that are tolerant of the cold climate.  However, the extreme  heat we also receive can be more of a problem.  So, we have placed the coop in a location that receives a lot of shade from our home and backyard trees.

Although the coop will not be built into the ground -- we are going to incorporate the insulating features of a living roof.  Our roof will contain four inches of lighter-weight growing medium and will contain drought-tolerant plants including sedums, creeping thyme, and (of course) some hens and chicks.  We are currently propagating several plants from our yard to be used on the roof -- this will help keep the cost down, as well as ensure that the plants we are using will grow well in our area.

Retrofitting a home for a living roof may involve hiring an engineer to determine if your existing roof has sufficient support for the additional weight.  However, since we are building from scratch -- we will be designing the structure to hold the additional weight.  We can't wait to try out this old idea to help keep our chickens comfortable and add more plants to our backyard.