Green Roofing has occurred in Canada since the Vikings brought the concept over to the Maritime Provinces. It is one of the most effective styles of insulation; Green roofing has been used in Scandinavia to contain hot air and in Tanzania to retain cold air. Making a green roof is simple and easy to maintain here is my guide on how to design your own. My instructions are not for a professional green roof, (consideration toward building regulations must happen before construction).

Materials:

Pond Liner x2 –Using pond liner you prevent excess water, debris, and roots from reaching the roof. Doubling the liner is just for added security.

Root membrane- In order to stop root growth and dirt from reaching the gravel layer, to avoid preventing drainage.

Gravel- The gravel allows free flow of water between the pond liner and the root membrane

1 Damp Carpet- Specialists prefer moisture blankets but it is much more costly. The more price sensitive alternative is an old damp rug; the synthetic fibers won’t rot unlike the well cited idea of using blankets and newspaper (to protect against further problems this technique is less favourable).

Mulch (wood chips) – Gardens retain water more effectively if the direct sun is blocked; mulch provides great water retention and acts as a buffer.

Triple mix- Triple mix is the most effective soil for its price it contains; Sand, Dirt, and clay which prevents water loss.

Insulation (If desired/ required by law)- You can use any type of thermal insulation if it is required although the living roof acts as an insulator; insulation should be considered if by-laws require it for calculations.

Step 1:

The roof structure should already be in place; along with the consideration of having a hugely increased deadweight. Extra support should be added to the structure to guarantee stability.

Install the insulation if required.

Roll the Pond liner cut to length along the roof. Keep in mind that this has to protect the roof structure from water leaks; also keeping in mind that if “ponding” occurs the integrity of the roof is risked, drainage at this level must be adequate.

Use the excess liner to reinforce the drain off the side

Repeat with second pond liner for extra security.

Step 2:

Spread gravel over the 2 layers of pond liner in order to allow free flowing water to move between the layers.

Roll the root membrane over the gravel

Lay 1.5x the amount of gravel used in the first layer over the membrane.

Step 3:

Place the carpet over the root membrane with a 6-8” border. Dampen the rug in order for moisture to be held.

Pour a layer of small pebbles over the damp carpet

Pour gravel, small stones, or decorative rocks around the border where the rug isn’t.

Tape the pond liner down with self-adhesive tape in order to prevent leakage.

Step 4:

Cover the rug in a layer of mulch; make sure not to go too thin this is to retain water.

Cover the mulch in triple mix to grow the plants.

Take a tamper and lightly tamp down the dirt in order for the garden to not lose the dirt over time

Take patio slabs and level them in order to place a ladder on. This is to stop from damaging your protective layers.

Step 5:

Pick some plants that spread nicely you’ll want to cover as much dirt as possible to get desired effects.

http://www.instructables.com/id/Build-a-Living-Roof-Green-Roof/?ALLSTEPS

http://www.cmhc-schl.gc.ca/en/inpr/bude/himu/coedar/upload/Design-Guidelines-for-Green-Roofs.pdf