This green roof is built on a century old heritage building in Toronto’s Junction neighbourhood. The former grocery store below has been divided into a modern residence and small retail store. The owner is converting a former wooden shaft elevator into a spiral stair case that will lead to a roof top garden that will adjoin the extensive green roof of sedums, chives, and nodding wild onions.

The timber frame construction was strengthened with steel posts and beams to allow a green roof to be constructed. The growing medium is variable in depth (1 to 4″) and is made from limestone and expanded shale. An un-irrigated blend of sedums mixed with chives and nodding onions was established with plugs and cuttings. The roof greened up in only 6 months, making the cost less than half of what an equavalent pre-grown system would cost. The lean soil favours the selected plants in the design, while starving weeds that sprout from wind and bird transported seeds such as crab grass, green foxtail, ragweed, horseweed, and dandelions.

green roof is designed with a poly-ethylene foam drainage panel made from 100% recycled local materials. This drain layer stores water in an oxygenated state which is critical for mitigated winter kill of sedums and other succulent plants during the freeze-thaw cylcle of late winter.