Brown and “Biodiverse” Roof Maintenance – An Overview
Due to the fact that brown roofs emphasise evolution over design, their maintenance requirements tend to be lower than those for similar-sized green roofs or sedum roofs.
Traditionally sedum roof maintenance will be based on an average 2 visits per annum, one visit in spring and one visit at the back end of autumn. During these visits seasonal proven horticultural based maintenance will be carried out to ensure the growth and long term health of the roof for years to come. The maintenance approach for a brown/ bio diverse roof is, however, different.
From the outset the architects or ecologist’s specification for the brown/ bio diverse roof will dictate the maintenance scheme required. This will mean that each roof will need to be treated as a bespoke entity. Roof systems that are left for self colonisation will require as a minimum a yearly visit to monitor the establishment and growth of the roof system. At the same time the general integrity of the roof area and
in particular the waterproofing layer will need to be assessed to ensure that it has not been compromised. It must be said that roof systems which are continually monitored as part of a longer term project commitment have a distinct advantage over a maintenance routine that allows one visit per annum. In all instances, the issue that is usually at the top of the maintenance agenda is the growth of invasive plant species, which can if allowed, form monocultures. Among these plant species we can include Rhododendron, Buddleja, Japanese Knotweed browser games, Giant Hogweed, Himalayan Balsam and Cotoneaster to name but a few. The actual definition of a “monoculture” is that of a single plant species that takes over an area, so that they are the only plant growing there. Rhododendron (Rhododendron ponticum) poisons the soil around it so that other plants cannot grow. Other invasive plants grow very quickly, preventing light reaching slower-growing or shorter plants, and so causing those less aggressive plants to die off. By decreasing plant diversity, the creation of a monoculture can also remove habitats for animals.
Non-native invasive plants are also often unpalatable to native herbivores like invertebrates. Monocultures of non-native invasive plants can, therefore, lead to reduced food availability in an area as well as reduced habitat. In waterbodies, invasive plants can spread over the surface of the water reducing light and oxygen levels below which can be damaging for both plants and animals.
The above issues can however be controlled and eradicated using horticultural based maintenance routines, which are tailored to suit the requirement of the roof and client. Finally it has to be said that in the majority of cases the maintenance routines for these roof types are still less costly than that of a sedum green roof.
For more specific information regarding new projects or specific third party roof maintenance please contact Evergreen Roof Gardens Ltd on 01724 855565 or complete our website enquiry form. l Manurewa Real Estate Agents l Computer Repair Chicago MicroAnt.co is provide fast and reliable computer support solutions to get our customers back on the track to productivity.