Extensive green roof systems are generally intended to be viewed from another location as a decorative/ ecological feature. They are not normally used as a recreational space to be walked through or sat in and often have limited access used for maintenance only. Due to the shallower substrate depths of extensive systems, the plant choices are more restricted to drought tolerant species such as sedums, grasses, wildflowers and mosses.
Extensive green roof build-ups can be installed above the completed Parabit Duo Hot Melt Roofing System, acting as ballast and a water attenuation system. For further assistance, refer to the Icopal Green Roof section of this website or contact Icopal’s Technical Department.
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Concrete Deck |
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Rootbar Sand Protection Layer Membrane |
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Icopal Siplast Primer |
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XPS/EPS Insulation |
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Parabit Duo Hot-Melt Compound |
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Water Reducing Layer / Filter Fleece |
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Parabit Duo Reinforcing Fabric |
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Icopal Extensive Substrate |
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Parabit Duo Hot-Melt Compound |
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Sedum vegetation |
Waterproofing System
Install the Parabit Duo Hot Melt Waterproofing System in accordance with the methods outlined in the Parabit Duo installation guide, inclusive of the Rootbar Sand protection layer.
Note: Prior to application of any ballast or thermal insulation, it is recommended that the finished hot melt roofing membrane be electronically integrity tested to ensure the flat roof has been thoroughly inspected, checked and passed off as being watertight.
Root Protection Layer
For green roof system build-ups, Rootbar Sand Protection Layer is installed instead of the standard Power Elastomeric 250 Protection Layer, install Icopal Rootbar Capsheet, directly to the Power Elastomeric 250 layer.
Rootbar Capsheet membranes are applied by torch-on application using a standard roofer’s torch. The membranes should be heated carefully ensuring the heat dispersible film on the underside is completely removed as work proceeds and ensuring a continuous 5mm bead of bitumen is extruded from all laps. Side laps must follow the manufactured mineral free selvedge with end laps a minimum of 150mm. The cap sheet should be offset 300mm from the Power Elastomeric 250 to avoid side build up. End laps should also be offset.
At the end of the working day, all areas should be completely sealed.
Drainage Layer (depending upon specification)
Where rapid removal of rainwater is desired or where installing above a flat roof deck with zero falls, install an appropriate drainage board over the completed Parabit Duo Hot Melt Roofing System immediately after the leak detection test on horizontal surfaces. If testing is delayed, install a temporary covering to protect the Parabit Duo Hot Melt Roofing System from damage by other trades.
Thermal Insulation
Where specified, install the thermal insulation in accordance with current instructions.
Surfaces should be clean and free of debris.
Inverted roof insulation boards are laid above the completed waterproofing system in a staggered, break-bond pattern ensuring all boards are laid flat and close butted to minimise cold bridging. The insulation boards should be cut accurately around any penetrations using a fine tooth saw or hot wire cutter.
The insulation boards should be laid in conjunction with a filtration (fleece) layer in an advancing manner, with appropriate ballast subsequently distributed to restrain the system.
The filter fleece must be laid with a minimum 150mm overlaps. If using Monarperm water reducing layer laps must be sealed immediately after positioning using Monobond LT double sided tape. Ensure a full seal at all joints by applying firm even pressure with a hand roller. All penetrations through the membrane should also be carefully sealed.
Green Roof System /Ballast
Install the green roof system, in accordance with project specification and current installation guidelines.
Please refer to Icopal’s green roof section of this website for clarification of green roof specifications or contact Icopal’s Technical Department.