Edgings for Green Roofs

Edgings for green roofs

…..are intrinsic to the success and the longevity of the entire green roof build up.  So, whatever the planting plan, depth of growing medium, type of waterproofing or pitch,  a green roof edging of one kind or another is absolutely essential.

green roof with a metal edging

A good green roof edging should:

• Neaten the appearance of the roof by hiding the build up
• Prevent wind uplift
• Allow excess rainwater to drain away
• Help minimise slippage.
• Be firmly fixed so that it cannot be dislodged during installation or maintenance
• Be made from a material that matches or compliments the building.

A good green roof edging will not:

• Damage the building or the waterproofing

How to make a timber edge for a green roof:

Here is a suggestion for a timber green roof edging on a pitched-roofed garden building using an Enviromat green roof kit

1. Firstly, ensure waterproofing is in place and in good condition
2. Then, cover the waterproofing with a protective layer of polythene (or butyl pond liner)
3. This will protect it against root damage
4. Using screws, Affix some wooden blocks to the edge of the roof.
5. We recommend that the blocks are at least 2cm thick and spaced evenly along the length of the building, approximately 50cm apart.
6. These are spacers to enable water to run off the roof without being obstructed by the edging.
7. Fixing them to the side of the roof ensures that the integrity of the waterproofing is not threatened.
8. Fix a timber fascia board to the spacer blocks.
9. To be able to hide the Enviromat green roof build up, the fascia must rise at least 5cm above the surface of the roof.
10. Ideally, it will have been pressure treated or brushed with preservative before being fitted.
11. If you wish, fix another board, at right angles to the fascia to help secure the green roof build up….this is more aesthetic than anything.
12. Following the instructions that come with the Enviromat green roof kit, install your sedum roof
13. Be sure to tuck the layers underneath the top fascia as per the diagram below.