This design incorporates a "sod" roof of locally harvested mosses as well as integrated benches. The entire structure except the plywood on the roof is constructed of red cedar. Most of the pieces were fabricated in a wood shop and then carried out and installed.
A waterproof membrane was attached to plywood and then old fishing net was draped over the roof to provide the moss with a stable foundation.
The bridge has considerable spring to it - it has a few inches of travel just walking on it normally. Bouncing on it will flex it (the section that isn't supported in the center) about 8 or 9 inches.
Total project cost: just over $10,000 not including donations and a few hundred hours of volunteer labor.