Sustainable Pet‘s Stephanie Rubin takes a cue from ecologically responsible house building techniques and applies them beautifully to these artistic Dog dens. The Green Roof system has been in use since the 1960’s as a great insulator and stylish look for house roofs – with a 3 inch base of soil and gravel. The plants on top serve as an incredible insulator, virtually “mute” barking inside the den and help with filtering rain water into pure drinking water. Thin copper tubing directs the purified water into a waiting bowl – and with that your dog’s carbon footprint dwindles even further. The plants used for the roof include native Grasses, Strawberry plants, Mint and wild Lettuce. These plants are all native to the California region but if you order from another part of the country they will custom select plants that are native to your region. The sculptural LeafBox house design is built out of naturally rot-resistant Red cedar and is further waterproofed with natural Beeswax. Sustainable Pet offers a full range of 5 sizes ranging in price from $2000 to $6000.