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Ecological Consultancy Habitat & Species Management Field Equipment & Wildlife Features

Green Roof Turf Specifications
and Installation Guide

Green Roof Specification

Saturated weights:
Turf – 35kg/m²
100mm substrate – 90kg/m²
Drip Irrigation – 5kg/m²

  Roof Pitch:
Any pitch possible
Turf can be pegged or wired
Roots quickly anchor turf to substrate

  Growth pattern:
All year round green cover
Plant development starts in spring and by mid-summer is approximately 45mm (18”) high
Plants established over winter with dormant growth patterns

Wildflower Species

Latin Name

Description

Autumn Hawkbit Leontodon autumnalis Yellow dandelion-like flowers
Birdsfoot Trefoil Lotus corniculatus Yellow/orange 'pea-flower', foodplant of several butterflies
Black Medick Medicago lupulina Small crawling yellow 'pea-flower'
Bladder Campion Silene vulgaris White flower with cut petals
Clustered Bellflower Campanula glomerata Attractive deep violet bellflower
Common Knapweed Centaurea nigra Pretty purple flower, favourite of bees
Common Poppy Papaver rhoeas The ever-popular bright red poppy
Common Spotted Orchid Dactylorhiza fuchsii Pale pink orchid of grassland
Common Toadflax Linaria vulgaris Bright yellow 'snapdragon-like' flowers
Common Vetch Vicia sativa Reddish-purple scrambling 'pea-flower'
Corncockle Agrostemma githago Beautiful, and now rare, pink flower of disturbed ground
Cornflower Centaurea cyanus Lovely blue flower
Cowslip Primula veris Pretty yellow drooping member of the primrose family
Hoary Plantain Plantago media Very popular flower with insects
Lesser Stitchwort Stellaria graminea Pretty white flowers with 'cut' petals
Wild Marjoram Origanum vulgare Lovely pinky-purple wild herb
Musk Mallow Malva moschata Gorgeous pink mallow
Perforate St Johns-Wort Hypericum perforatum Lovely yellow flower
Wild Red Clover  Trifolium pratense Bees love this flower!!
Rough Hawkbit Leotodon hispidus Another 'dandelion-like' flower
Self-heal Prunella vulgaris Pretty purple flowers on a short stem
Scarlet Pimpernel Anagallis arvensis The familiar red flower of bare ground
Sheep's-bit Jasione montana Pretty little purple flower of grassland
Small Scabious Scabiosa columbaria Pinker version of Sheep's-bit
Thrift Armeria maritima Lovely pink flower in green tufts of leaves
Vipers Bugloss Echium vulgare Hairy plant with blue flowers
Wild Basil Clinopodium vulgare Pinky-purple herb of grassland
Wild Pansy (Heartsease) Viola tricolor Tiny violet/yellow pansy
Wild Thyme Thymus praecox ssp. brittanicus Aromatic purple herb
Yarrow Milfoil Achillea millefolium White flowers with feathery leaves
Yellow Rattle Rhinanthus minor Lovely yellow flowers and rattling seed-cases
     
Grasses (Common Name) Latin Name
Sheeps Fescue Festuca ovina
Creeping Red Fescue Festuca rubra ssp. littoralis
Crested Dogs Tail Cynosurus cristatus

Sedum (included in Wildflower Roof Plus Turf)


Sedum (Common Name) Latin Name Description
Chubby Fingers Sedum alba White with pale green leaves
Orpine Sedum ellacombianum Yellow (leaves turn pink in Autumn)
Baileys Gold Sedum kamschaticum v. floriferum Yellow with blue-green leaves
Stonecrop Sedum hybridum Large star-like  yellow
Lime Stonecrop Sedum pulchellum Pink with lime coloured leaves
Blue Stonecrop Sedum reflexum Yellow with grey-blue leaves
Tasteless Stonecrop Sedum sexangulare Yellow with pale green leaves
Rockcress Sedum spurium Pink with pink-tipped leaves
Green Roof Laying Guide

Introduction:

Here is our pictorial guide for the establishment of our simple green roof system. The intention is to give a step by step account of how to install the Wildflower Turf roof system. Our turf is suitable for any green roof project using any manufacturers product.

Before starting:

Ensure that the roof structure is of sufficient strength and suitably designed to support the combined saturated weight of the turf, substrate and irrigation system. If unsure, it is advisable to consult a structural engineer, architect, or specialist contractor.

Safety Note:

Please ensure that it is safe to work on the roof. If in doubt please refer to the Health & Safety Executive web site for further guidance and availability of publications.




1. Waterproof Membrane

Lay a waterproof membrane over the entire roof area. Consult a roofing contractor for an appropriate system.

Pay attention to sealing around roof lights, vent stacks and other similar features where there is a higher risk of water ingress.

The whole roof must be watertight. Take care not to puncture the membrane.

 

 

Green Roof Membrane Sealing

One manufacturers product using a single ply membrane

2. Substrate Retention

When using loose substrate, and in particular on steeply pitched roofs, provision must be made for a retaining system at the eaves and sides of the roof. This can be in the form of a wooden batten/barge board with accompanying fixing brackets or an engineered metal L shaped strip attached to the roof structure. Your architect or roofing contractor should advise you on the design and construction of this feature. Attention should be made to the water-tightness of fixing points.

 

Green Roof Barge Board

Engineered metal L shaped retaining profile

In addition to eaves retention it is advisable to install a line of our woven substrate sacks around the perimeter of the roof which provides the initial containment of the loose substrate whilst the turf establishes a root system.

 

 

Roof with liner

Eaves and ridge substrate sacks


3. Drainage

Adequate provision must be made for drainage at the bottom of the roof slopes. This can be achieved by leaving a small gap in the retention feature, or a strip back-filled with gravel or similar material.

 

 

 

 

 

Stable roof

Barge board and gutter system

If rainwater collection is desirable, a gutter can be installed draining to a suitable collection point.

 

Guttering

Gravel and open gutter system

4. Substrate Layer Options

Option 1 - Loose substrate

Lay a strip of geo-textile permeable membrane along the inside of the barge board to allow water to drain without washing out any substrate/soil in the process.

 

 

Membrane and Netting

Permeable retaining material

Fill area with substrate laid evenly at 100mm depth. Remember to allow 10% extra for settlement.

 

 

Spreading loose substrate

Spreading loose substrate

 

Option 2 - Mixed & Loose substrate and Substrate sacks

Using our 600x460x100mm woven substrate sacks, allow 3.8 sacks per m².

Lay two lines of sacks around the perimeter of the roof and along the ridge.

Backfill the remainder of the area with loose substrate to the same level as the sacks allowing 10% extra for settlement.

 

Substrate layer on green roof

Mixed substrate - bagged and loose substrate combination.

Use some of the loose substrate to fill in the small spaces between the substrate sacks.

 

 

Stable green roof

Fully screeded

 

Option 3 - Substrate layer using sacks only

Using our 600x460x100mm woven substrate sacks (allowing 3.8 sacks per m²) cover the whole roof area. Using sacks helps to give permanent structural strength.

 

Substrate sacks

Substrate sacks

Using loose substrate, apply a screed layer of substrate over the substrate sacks and brush in to ensure any gaps are properly filled.

 

Paultons Park

Sacks and Screed

 

5. Irrigation (optional, but recommended)

Lay drip irrigation system, if required (recommended). Pipes should be laid across the gradient of the roof slope with T joints to a vertical supply/feeder pipe.

Please request information about our irrigation kits.

 

Green Roof Irrigation

Drip irrigation kit installed

6. Laying Turf

Lay the turf paying attention to abutting turf joints and ensuring turf roots are in contact with the substrate. Any gaps should be filled with loose substrate.

 

Turf Laying on the green roof

Turf laying in progress

7. Watering

Water turf daily (if it does not rain) until the roots have established (allow two weeks minimum).

Do not flood the turf when watering but ensure the substrate is damp.

Once established revert to occasional watering as per the maintenance sheet.

 

Watering the roof

 

8. After Care


For aftercare after the green roof is established please refer to our maintenance sheet below.




Water

Water well while the turf establishes itself. Lift a corner of the turf to check that the growing medium beneath the turf is also damp.

Future water requirements will be dependent on substrate type and depth. Watering the turf during the summer months and dry spells will prolong the flowering period. A leaky pipe irrigation system installed beneath the turf is the ideal way to cover all eventualities.


Cutting

One cut per year is required in late summer/autumn – strim, mow or cut with shears to a height of 2-3 inches (50-75mm). Rake up and remove cut material and ensure that no decaying material is left on the turf as this will suppress future growth and prevent germination of new seeds. An open sward over the winter ensures healthy, disease free plants which can benefit from what light is available to them during these months. As the spring approaches the wildflowers and grasses are in the perfect position to develop flowers and seed heads quickly to repeat their life cycle.



Fertiliser

There is minimal requirement for fertiliser. An occasional dressing may be required with certain types of substrate/growing medium. Please contact us for more information and advice.


Once the turf has flowered and set seed the roof becomes self sustaining. New seeds will drop after flowering and these will germinate to provide flowers for the following season.


Safety Note:

Working at height on a roof is hazardous. Extreme care must be taken when carrying out any work and it is essential that it is safe to carry out the work. Do not work alone. Emergency procedures must be put in place prior to carrying out any work whatever and whoever it involves in case there is an accident.

Business users and contractors must undertake full risk assessments where appropriate prior to carrying out operations and abide by the relevant Health & Safety regulations relating to the tasks being carried out. Please refer to the Health & Safety Executive website for further information. If in doubt, do not proceed with the work but seek further advice.

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