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Green roofs

Many products that aim to make the construction of green roofs simpler and more efficient are now available, including pre-seeded blankets, planted modules and drainage layers

A standard construction practice in many other countries for years, green roofs have been used for their insulative properties. Until recently they were considered a vernacular building practice, yet since the 1960s an increased concern for the environment has driven the rise in their popularity, addressing
the decline in green space that exists within urban areas.

Green roofs have significant environmental benefits. In urban areas they can reduce the urban heat island effect, which is caused by increased development. They also increase biodiversity and create habitats within our urban centres. The use of green roofs can form part of a sustainable urban drainage solution. These roofs reduce the amount of water being released into the sewer system, particularly useful during a storm situation when they slow the initial surge of stormwater runoff . For these reasons their use is increasingly being incorporated into policy. In 2008 the revised London Plan moved from encouraging green roofs to expecting them on all major developments.

There are two main types of green roof: extensive and intensive. Extensive roofs are typically 50-150mm in depth and are lightweight. They will often feature plants such as sedums, mosses and grasses. Intensive roofs are - as their name suggests - much more substantial. Their build up can total as much as 1,500mm and they usually contain a mix of hard and soft landscape, featuring trees and shrubs.

A green roof, whether intensive or extensive, will have a basic build up comprising three layers: the drainage layer, a filter layer and the vegetation layer. The depth and the specification of each of these layers will differ dependent on the plants that are to be supported.

The roof structure is an important consideration in green-roof design. A rough guide to loadings would suggest that an extensive roof can weigh anything from 60 to 150kg/m², and an intensive roof up to 500kg/m². If a green roof is part of the initial design of the building, the structural engineer will be able to take this into consideration in structural calculations from the beginning; if the green roof is added at a later stage, however, costs can rise.

Oldroyd Xv green

Oldroyd Xv green

Oldroyd Xv green

A damp-proof membrane designed for use on green roofs. The rubberised outer layer on both sides minimises slipping of the membrane on the roof during laying, providing further grip when laying the turf or sedum.

Manufacturer Oldroyd
Product Roofing membrane
Application Pitched turf and green planted roofs
Material Polypropylene
Recycled content Minimum 49 per cent recycled inner core
Guarantee 50 years
Country of manufacture Norway
UK distribution West Sussex

www.oldroyd.com


Oldroyd Xv20 greenXtra

Oldroyd Xv20 greenXtra

Oldroyd Xv20 greenXtra

Oldroyd Xv20 greenXtra is a perforated membrane with a 20mm deep stud specifically designed for green-roof use. The studs collectively form a rainwater reservoir, providing water for the roof plantings, which is useful in areas of low rainfall.

Manufacturer Oldroyd
Product Drainage layer
Application Flat green roofs and roof gardens, brown and biodiverse roofs
Material Polypropylene
Recycled content Minimum 49 per cent recycled inner core
Guarantee 50 years
Country of manufacture Norway
UK distribution West Sussex

www.oldroyd.com

Foamglas T4

Foamglas T4

Foamglas T4

Foamglas insulation has good levels of compressive strength and resistance to moisture, which makes it particularly well suited to green-roof applications. It also resists degradation from root penetration.

Manufacturer Pittsburgh Corning
Product Insulation
Application Flat green roofs and roof gardens
Material Recycled and new glass
Recycled content 66 per cent waste glass
Size 600 x 450mm
Thermal conductivity 0.042W/mK
Life expectancy 100 years
Country of manufacture Europe
UK distribution Berkshire

www.foamglas.co.uk

CT Flora Roof

CT Flora Roof

CT Flora Roof

This turf is provided with a 50:50 mix of wildflowers and grass, and is an alternative to seeding or plug planting. It can be used to create a wildflower meadow on a green roof.

Manufacturer Wildflower Turf
Product Turf
Application Flat green roofs and roof gardens
Material Turf, grasses and wildflowers
Roll size 1.25m²
Maintenance required One cut per year
Country of manufacture UK
UK distribution Hampshire

www.wildflowerturf.co.uk

Sempergreen Green Roof Module

Sempergreen Green Roof Module

Sempergreen Green Roof Module

This module tray is designed for use on extensive green roofs. They are pre-planted with a variety of 6-8 sedums. Due to its prefabricated nature, it is quick and easy to install, keeping costs down.

Manufacturer Den Ouden
Product Planting module
Application Extensive green roofs
Material Recycled plastic tray with sedums
Module size 570 x 380 x 80mm
Weight 75kg/m²
Country of manufacture The Netherlands

www.denoudenexport.com

Sedum Matting

Sedum Matting

Sedum Matting

This product is a pre-planted matting suitable for use on green roofs. The sedum mat typically adapts well to poor soil and exposed sites making it a good alternative to grass.

Manufacturer Enviromat
Product Plant matting
Application Extensive green roofs
Material Matting with pre-seeded sedums
Roll size 2m²
Country of manufacture UK
UK distribution Norfolk

www.enviromat.co.uk

Xero Flor XF300

Xero Flor XF300

Xero Flor XF300

For this plant matting the plants are grown on a blanket, which is harvested like turf and then laid out above the waterproofing layer. The blankets are very lightweight, easy to maintain and provide instant greening to the roof.

Manufacturer Bauder
Product Plant matting
Application Extensive flat sedum green roofs
Material Fleece sheet with 11 species of sedum in a crushed brick and composted pine bark-growing medium
Roll size Up to 10m in length
Weight 34kg/m²
Guarantee 20 years
Country of manufacture UK

www.bauder.co.uk

NatureMat

NatureMat

NatureMat

NatureMat is a pre-cultivated sedum carpet that consists of a biodegradable base layer and a plant layer. These mats achieve a coverage of 90 per cent sedum.

Manufacturer Blackdown
Product Plant matting
Application Extensive sloped sedum green roofs
Material Growing medium layer with pre-seeded sedums
Roll size 1 x 1.5m
Country of manufacture UK

www.blackdown.co.uk

Floradrain 25

Floradrain 25

Floradrain 25

Alumasc’s Floradrain system provides a layer that stores rainfall, holding it in the system so it can irrigate the plants as needed. It can retain up to three litres of water per square metre.

Manufacturer Alumasc
Product Drainage layer
Application Extensive green roofs below a shallow substrate
Material Recycled high-density polyethylene
Size 1 x 2m sheets
Weight 4.7kg/m² (saturated)
Build-up height 25mm
Country of manufacture UK

www.alumasc-exteriors.co.uk

Zincolit Drainage Substrate

Zincolit Drainage Substrate

Zincolit Drainage Substrate

Zincolit substrate is used to act as a medium for bedding in permeable paving, while acting as a drainage layer for deep applications of green-roof substrate.

Manufacturer Alumasc
Product Drainage substrate
Application Intensive green roofs
Material Recycled crushed brick
Particle size 4-15mm
Weight 1400kg/m³ (saturated)
Country of manufacture UK

www.thermoboard.wavin.com

Floraset

Floraset

Floraset

A lightweight drainage board particularly designed for roofs with little or no drainage falls. The board collects water in its storage cells, while a multidirectional
channel system on the underside allows positive drainage of any excess.

Manufacturer Alumasc
Product Drainage layer
Application Extensive green roofs
Material Recycled expanded polystyrene
Size 1m²
Weight 2.7kg/m² (saturated)
Build-up height 50mm
Country of manufacture UK

www.alumasc-exteriors.co.uk

Graviflex Anti-root Barrier Cap Sheet

Graviflex Anti-root Barrier Cap Sheet

Graviflex Anti-root Barrier Cap Sheet

This bitumen sheet is torch applied to the roof surface, sealing off the structural layer from any root ingress, preventing damage. The green roof can then be built up above.

Manufacturer Langley
Product Root barrier
Application Extensive and intensive green roofs
Material Bitumen sheet with slate chip top
Roll size 8m²
Weight 38.5kg/roll
Thickness 3.2mm
Country of manufacture UK

www.langley.co.uk

Green Roof Cultivated Mat

Green Roof Cultivated Mat

Green Roof Cultivated Mat

Grown in the UK, these mats can be dispatched at short lead in times with the minimum of transportation. The sedum plants are naturally hardened to the UK environment during their initial growing process.

Manufacturer Langley
Product Plant matting
Application Extensive sedum green roofs
Material Mixture of sedum varieties in substrate
Mat size 500 x 500mm
Height 75mm
Weight 56kg/m² (saturated)
Country of manufacture UK

www.langley.co.uk

Biodrain Mat

Biodrain Mat

Biodrain Mat

Langley’s Biodrain is produced from recycled foam with a cuspated base layer. The cuspate design allows for drainage of excess water, while the foam material provides a water retention layer, feeding the system above. The drainage layer is a recycled material free from polyurethanes.

Manufacturer Langley
Product Drainage matting
Application Extensive sedum green roofs
Material Recyled open pore, emission free PUR soft foam
Mat size 1m x 0.75m
Height 30mm (trough of cuspate 15mm)
Weight 8kg/m² (saturated)
Country of manufacture UK

www.langley.co.uk

 

 

 

 

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