A Living Roof

closet shed in need of some roof work

We bought new wood to replace the old roof on the shed. During the planning stage I decided that I wanted to try a living roof (extensive). It's a small surface and it wouldn't cost a whole lot .  Decided this would make a great experiment.  I had some waterproof membrane, landscape fabric for a filter and I used cut up old flats filled with soil.  Once positioned I planted them out with groundcovers. When it was completed I decided on 3 ground covers, sedum, moss and thyme. It took a couple of hours to build and once up and planted I was quite surprised at the overall look. I think once the ground covers grow in I will like it even more.

New roof complete with groundcovers

 There are two main types of green roofs: “extensive”(depth of 15cm (6inches) or less) or “intensive”, (depth is 6" or more) depending on the depth of growing medium and amount of maintenance.
Extensive green roofs are typical in residential and intensive would be found in industrial or apartment roof tops (large flat or slightly slopes grades) 

List of materials for an extensive living roof are as follows:
Start with a waterproofing layer (if the roof or surface is already shingled this will do)
       pond liners work well for this.
Insulation - a thin sheet of rigid insulation works well for this or batting in the rafters under your roof.

Drainage, water retention and filter layer -act as root barriers.  Help manage the amount of water that is retained on the roof and ensure that the growing medium doesn’t clog the drainage layer and wash away.

Growing medium. This is usually a lightweight, custom mixture, composed mostly of expanded stone, volcanic rock, perlite, with only a 10% to 20% organic content. The goal is to find a balance between a soil that will sustain the plants, but that won’t weigh so much as to require excessive support from the building structure.

Plants - remember to choose plants that can be sustained in the growing depth of your roof.