179 bauder.co.ukIRRIGATIONAll intensive green roofs with areas of soft landscaping must incorporate a permanent irrigation system regardless of construction type or site location. This vital element should never be disregarded or excluded, because without it, the plants will find it very difficult to survive for the long-term in a healthy condition.Although water is retained in the growing medium and water storage products within some systems, this only serves to reduce the frequency of irrigation, particularly if the growing medium is shallow. It will not compensate for prolonged periods of warm, dry, weather where there is a lack of adequate rainfall.Automated irrigation is generally the best option in the long-term. There are many different types of irrigation system available ranging from fully automated systems with pop-up sprinklers to simple leaky pipe systems.Where the roof design is mostly soft landscaping, a simple and environmentally friendly method of irrigation is to create a reservoir of water beneath the Bauder DSE60 by means of inserting damming pieces in the outlets. A self-regulating irrigation unit set on the deck, enclosing a float connected to a water inlet valve, keeps the reservoir topped up. The water diffuses up through the drainage layer to feed the plants. For this system to work, the deck must be to zero degree falls, and there must be a continuous abutment upstand around the perimeter to retain the reservoir of water.On the whole, the type of irrigation and frequency of application will depend on the plant species chosen, their requirements and the prevailing weather conditions. Therefore, the system selected should follow the recommendations of the appointed landscape architect or nominated horticultural specialist and be installed strictly in accordance with the manufacturers recommendations.? Perforated pipe irrigation installed within a raised brick built planter? An example of a wall mounted control box used in conjunction with an automated irrigation systemPhotographs courtesy of Access Irrigation LtdINTENSIVETECHNICAL GUIDE
bauder.ie180GENERAL MAINTENANCE? Routine maintenance is essential to prevent weeds etc. from establishing.Intensive green roofs require the same level of routine maintenance that would be expected for ground level landscaping, but in addition will include inspection and maintenance of features relating to waterproofing system on a flat roof. The following issues need to be considered:AcesThe roof must be readily accessible to carry out maintenance tasks and irrigation where an automatic system is not installed (applicable usually to small roof areas only). Roof level access and defined walkways should be incorporated within the design.Inspection of rainwater outletsIt is important that excess water can drain freely. A primary requirement of any routine maintenance schedule is to ensure that the outlets remain free of any debris. Purpose designed inspection chambers should be installed and inspections carried out on a regular basis.Any overflow pipes to parapet walls should be inspected to ensure that they do not become blocked. The vegetation barriers, where installed, should be kept free from any plant encroachment.Perimeter flashings etc.Any protective metal flashings or termination bars should be checked to ensure that they remain securely fixed and in place. All mastic sealant should be examined for signs of degradation and renewed as required. The filter fleece should remain just visible and that the protection layer securely retained by the counter-flashing.Weds and SaplingsWhile new plants are establishing, weeds may compete for space and take hold. It is important to identify and quickly remove any undesired species before they have an opportunity to become established and spread.Irrigation System MaintenanceThe maintenance procedure should include any required maintenance to the irrigation system. The manufacturers instructions regarding maintenance should always be followed. During winter, some systems may need to be drained to prevent residual water from freezing in the pipes or water storage tank. The system should be re-commissioned in the spring.Tres In roof garden situations, trees require greater depths of soil, normally 500 - 600mm minimum, which imposes a greater localised structural load. They also have a critical impact on the immediate landscape that surrounds them because of their avid requirement for water. A correctly designed and regulated irrigation system is essential to maintain adequate moisture levels and prevent the tree from drawing most of the immediate moisture from the surrounding soil to the detriment of other plants.For trees contained within raised planters, it is wise to prune every three to four years to control the size of the rooting area and prevent the tree from outgrowing the container.We recommend that a routine maintenance schedule is drawn up and implemented. It is usual for the services of a landscape gardener or contractor to be employed to carry out this work.