Green Roof Systems
Introduction
Independent Research Due to the very wide range of environmental and economic benefits, green roofs have come to be important elements of sustainable and green construction in many countries. Moreover, because they can be highly visible, they also clearly outwardly signal an intent for sustainable building and can give a very positive and distinctive image to a building or development. Specific benefits of green roofs include: •
Research from around the world indicates that Green Roofs reduce annual run-off from roofs by at least 50%, and more usually by 6070% - contributing to urban drainage and flood alleviation schemes. Furthermore, the rate of release following heavy rainfall is slowed, reducing the problems associated with storm surges. With an increasing need for developments to have limited water run off, the Environment Agency now highlight the use of green roofing in their May 2003 publication “Sustainable Drainage Systems (SUDS) – an introduction”.
•
Green roofs can reduce the need for air conditioning in the summer and as a result reduce CO2 emissions.
•
New developments lead to a loss of habitats - green roofs can contribute to biodiversity and address local action plans. In particular they have been shown to favour many rare invertebrates found on brownfield sites, as well as ground nesting birds such as skylarks.
•
Green roofs contribute to a greener urban environment and quality of life for communities in high density developments.
•
A roof life could be doubled with the addition of a green roof, thereby reducing resources used in replacement and repair.
Information courtesy of the Green Roof Centre
Waterproofing
The Waterproof Solution Hertalan roofing systems are durable, flexible and environmentally friendly. Our membranes have been used successfully for decades throughout the world for over 40 years. Large pre-fabricated membranes can quickly and efficiently waterproof large areas and are installed without the use of naked flames. Our UK technical team can provide assistance in the specification and design and our approved contractor network can supply you with a complete green roof package to suit your requirements.
hertalan is the complete solution for those looking for a totally green roof • Custom made factory fabricated membranes • Manufacturer’s 20 Year Warranty • Environmentally friendly • Only installed by approved contractors • Root resistant to FLL standards
Options
Sedum Sedum systems are available as pre-grown modular units, mats, plugs, sprouts or seeds. The plants require minimum maintenance, are low in height, drought resistant and will regenerate seasonally. These systems can be lightweight and are often suitable for installing on existing roof structures.
Wildflower Wildflower meadows are a mixture of wild flowers and grasses growing in a moisture retentive biodegradable felt. They provide a range of flowers over an extended flowering season resulting in a visually pleasing effect and support a diverse range of bird, insect and animal species.
Pictorial Seeds Pictorial meadow mixtures are carefully blended seed mixes of native and non-native hardy annuals and perennials designed to provide high quality and cost effective flowering displays.
Natures Zone Often described as bio-diverse or brown roof systems these allow nature to naturally colonise the roof. It is possible to use clean building debris from the surrounding areas, reducing the need for waste disposal to landfill.
Important Considerations
What to find out next? Weight
What weight will the roof structure withstand? Ultimately this is the most important factor to consider when planning your roof garden. This will determine which green roof options are available to you.
Maintenance
How much maintenance do I want? Even the most basic green roof system requires a small amount of maintenance and dominant weeds should be removed on an annual basis. Intensive systems require a greater amount of maintenance and careful consideration should be given to whether access is practical and safe.
What do I need? Waterproofing
The most important element in any roofing project is the waterproofing. Hertalan EPDM membranes are durable, flexible and 100% root and UV resistant. Large pre-fabricated sheets can be made in factory conditions to reduce the necessity for on site seam bonding. Pre-formed TPE weldable corners, pipe covers, outlets etc are used for detail work to complete the installation.
Contractors
Hertalan is only installed by approved, trained and monitored contractors to ensure a high quality is achieved on your projects.
Certification
Hertalan production is strictly regulated by ISO 9001 and 14001 standards. Hertalan roofing systems have BBA, UEATc and Komo certificates and are root resistant to the German FLL standard.
Sedum System 9 10
KEY:
1.
Substrate
6.
2.
Hertalan butyl vapour control layer
Hertalan drainage and water retention board (D.B.)
7.
Extensive soil substrate (E.S.S.)
3.
Insulation
8.
Pre-grown Sedum blanket
4.
Hertalan EPDM (F.L.L. Tested)
9.
Aluminium retaining bars
5.
Hertalan protective moisture mat (P.M.M.)
10.
River washed gravel edge
Weight SATURATED UNSATURATED
60-100kg p/m2 40-60 kg p/m2
OVERALL DEPTH
DEPTH OF GROWING MEDIUM
N/A
40-70mm
Sedum systems can be installed on pitched roofs, however care must be taken when the pitch is 25O or above to prevent slippage of the substrate. The drawing above shows aluminium retention bars that are adhered to the surface of the membrane. Other options include combinations of drainage boards and jute netting or recycled plastic grids that can be interlocked.
Wildflower System 9 8 7 6 5 4 3 2 1
KEY:
1.
Substrate
6.
2.
Hertalan butyl vapour control layer
Hertalan drainage and water retention board (D.B.)
7.
Extensive soil substrate (E.S.S.)
3.
Insulation
8.
Pre-grown wild flower blanket
4.
Hertalan EPDM (F.L.L. Tested)
9.
Hertaled counter flashing
5.
Hertalan protective moisture mat (P.M.M.)
SATURATED UNSATURATED
Weight
OVERALL DEPTH
DEPTH OF GROWING MEDIUM
110-175kg p/m2 60-110 kg p/m2
N/A
75-125mm
Wildflower meadow systems are an innovative option that incorporates drought tolerant species such as - Yarrow, Lesser Knapweed, Lady’s Bedstraw, Cat’s Ear, Ox-Eye Daisy, Ribwort Plantain, Self Heal, Meadow Buttercup, Yellow Rattle and Salad Burnet. This system requires an annual cut to promote healthy growth the following year.
Intensive System 9 8 7 6 5 4 3 2 1
KEY:
1.
Substrate
6.
Fines layer
2.
Hertalan geo-textile layer
7.
Intensive soil substrate (I.S.S.)
3.
Hertalan EPDM (F.L.L. Tested)
8.
Turf layer
4.
Hertalan protective moisture mat (P.M.M.)
9.
Hertaled counter flashing
5.
Free draining stone layer
Weight SATURATED UNSATURATED
Dependant on required finish
OVERALL DEPTH
DEPTH OF GROWING MEDIUM
N/A
N/A
Intensive systems can be a combination of turf, shrubs or vegetation that require a greater depth and different mixture of growing substrate. These systems offer a wider choice of plantation, however the level of maintenance increases. Slow growing varieties of grass are available and can transform a rooftop into an aesthetically pleasing recreational area.
Pictorial Meadow System 9 8 7 6 5 4 3 2 1
KEY:
1.
Substrate
6.
2.
Hertalan butyl vapour control layer
Hertalan drainage and water retention board (D.B.)
7.
Extensive soil substrate (E.S.S.)
3.
Insulation
8.
Pictorial seed mix
4.
Hertalan EPDM (F.L.L. Tested)
9.
Hertaled counter flashing
5.
Hertalan protective moisture mat (P.M.M.)
SATURATED UNSATURATED
Weight
OVERALL DEPTH
DEPTH OF GROWING MEDIUM
110-175kg p/m2 60-110 kg p/m2
N/A
75-125mm
Pictorial meadow systems are a combination of seeds sown onto a substrate that germinate to produce a colourful burst of flowers. Other seeded systems include hardy perennial and annual mixes that also contain Sedum. The seed mix includes annuals which provide instant colour in year one, whilst the perennial species establish themselves.
+44 (0)1623 721 500
+44 (0)1623 721 500 +44 (0)1623 721 700
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+44 (0)1623 721 700
@
info@hertalan.co.uk
info@hertalan.co.uk www.hertalan.co.uk
Green Roof Solutions www.hertalan.co.uk
Green Roof Systems