This 32 storey apartment development was constructed with the aim of creating the most desirable address in Sheffield, with St Paul’s Place ideally situated to benefit from local amenities and transport infrastructure.
In order to help achieve this goal, it was decided from the outset of the project that the development had to be sympathetic to its surroundings and in line with plans to create a high scoring BREEAM building. The development is in the heart of Sheffield city centre where space is at an absolute premium. As with all developments, the client wished to maximise the footprint of the building, but appreciated that a green amenity area for the residents’ private use would add value to the development.
The ideal would be a space with trees and shrubs to give privacy around patio areas and to simulate a parkland area at roof level.
As with any intensive green roof, adding soil, water and drainage can be heavy and potentially structurally damaging elements. The below surface drainage system needed to control run-off to a fixed discharge rate, along with providing sufficient storage to maintain moist conditions for optimum plant growth. Trees and shrubs need a minimum of 500mm of moisture retaining fertile soil to flourish through the seasons. This was all to be achieved in very tight working conditions, with many additional service elements such as lighting cables to contend with.
A pleasing green amenity space for residents was created using an Intensive Green Roof system on a second storey flat roof, without impacting on the footprint of the development.
Included within the buildup of the roof was a load bearing void former SuDS tank, designed to attenuate rainfall and reduce flow to the level stipulated by the Environment Agency. The slim but high flow ABG blueroof System Type D was incorporated within the SuDS Intensive Green Roof buildup to allow free drainage of surcharge from the SuDS tank within the roof. The tanks were placed to form wells with the top and sides protected and filtered using a thick Abtex geotextile. Once the hard landscaping was placed around the wells, these were filled with light weight, high NPK moisture retaining soil. Selected hard wearing drought resistant shrubs and trees were planted to give an immediate green effect.
Void former attenuation storage system, lined with Abtex geotextile and installed onto drainage geocomposite.
The ABG Service
ABG roof design, installed by subcontractor Geogreen who delivered the works on time and to budget.