Harrowden - pebbles

We recommend these cobbles for use on green roof installations as a fire break, to provide free draining areas as well as for habitat creation on biodiverse roofs.

In terms of application, firstly in accordance with the GRO code garden cobbles should be installed 300mm wide around all perimeters, including rooflights and rain outlets.  Secondly, they should also be installed 500mm wide where there are building openings like doors, windows or opening roof lights. Finally, install the cobbles to a depth of 50mm or at least to the same depth as the substrate / plant layer.