Perimeters and vegetation barriers
The minimum required upstand height for the waterproofing at abutments, parapets or pipe work penetrations etc, is 150 mm above the completed landscape surface. The only exceptions are at perimeter kerbs where the waterproofing extends fully to the outer edge finishing in a traditional welted drip, edge trim or at access doorways, where a linear drain is incorporated. Flush threshold access doorways can normally be accommodated, and the design of the waterproofing detail at the threshold will vary dependent upon the components to be sealed to.
These are created with round washed pebbles and provide several important functions in a green roof:
- Prevent vegetation from encroaching on roof elements such as rainwater outlets
- Protection of the vegetation layer from water running down vertical upstand surfaces or from higher level rainwater downpipes.
- Provide rapid surface drainage during heavy rainfall.
- Reduce and ease routine maintenance.
- Protection of the waterproofing from mechanical damage during maintenance.
- Fire break, where the pebbles are installed at a minimum of 300mm wide and 50mm deep.
- Wind uplift resistance by increasing the imposed load at roof perimeters