September 2008 - Axter

1 Extensive and Intensive green roof TechnologySfB47 September 2008In general a green roof is one with plantsgrowing on its surface. This can rangefrom the spontaneous occurrence of lichenand moss on a roof surface to a fullylandscaped space including trees, shrubsand hard landscaping. There are manyvariations but in general green roofs havebeen divided into extensive, green roofs have lowmanagement requirements and do notusually require artificial irrigation. Basedon thin soil or substrate layers, plantingstyles are naturalistic with the object ofestablishing a self-sustaining plantcommunity, such as sedums or hardywildflower mixtures. An alternative isAxter s HYDROPACK ready plantedmodular tray (see separate HYDROPACK brochure). The main reasons for installingan extensive green roof are visual,creating habitat for native flora and fauna,and enhancing the building green roofs need similarmanagement to a ground level garden, usuallycomprise a deep soil or growing medium andrequire artificial irrigation.

2 They can be adaptedto accommodate virtually any type of plant and often include hard surfaces for access. The main reason for installing an intensivegreen roof is to provide amenity roofsIt is possible to replicate, on the roof , theenvironmentally diverse brown field sitesassociated with demolished buildings. In thisway building rubble can be easily recycledand vegetation associated with such sites cancolonise a range of low-fertility substrates, , sand, rottingtimber, specialises in the design of green roofsand in conjunction with horticultural experts willproduce bespoke design specifications foreach construction, covering all aspects ofwaterproofing and insulation, watermanagement and hard and soft BENEFITSD epending upon the type of roof gardenrequired the advantages include: Improved rainwater management Use of roof area as additional space Visually attractive with a range ofplants and foliage effects Low maintenance (extensive roofsonly) with little or no artificialirrigation Improved thermal performance Reduction in sound transmissionthrough the roof Improvement in air quality throughabsorption of carbon dioxide andrelease of oxygen Provision of habitat for wildlife; particularly important in city centredevelopments Reduces the environmental impactof the building within itssurroundingsThe green roof ConceptLeft: Extensive roof garden to office development.

3 Range of rockery type plantswith wooden duckboard : Semi-intensive roof garden on an industrial used as a single plant AND VALUE CHAINPARTNERINGE mbracing the ethos of Sir John Egan sreport Rethinking Construction, Axteractively promotes partnerships withparticipating contractors in order to deliverquality and value for money. AXTERSHIELDI nstallers are fully trained in the installationof Axter materials and are chosen becauseof their workmanship quality, their integrityand their ability to complete installationswith a minimum of technical orprogramming conflicts. AXTERSHIELDI nstallers will usually carry out installation of the insulation and waterproofing membranes althoughspecialist horticultural experts may complete the landscaping 20 year or longerguarantees are available if the waterproofingis installed by an cover failure due to water ingress asa result of a latent product or installationdefect.

4 Material warranties are alsoavailable for 10 or 15 s green roof systems have been usedworldwide. Recent contracts in the UKinclude: BedZED, the Beddington Zero EnergyDevelopment, Sutton, Surrey Procter and Gamble HQWeybridge, Surrey BBC White City, London Paddington Basin Development, London Northampton Academy West One Development, Devonshire green , Sheffield Primary School, Hadleigh, Suffolk Ecology Building Society, Keighley, Yorks Tong High School, Bradford Riverside Quarter, Wandsworth Alibone Recycling Plant, Northampton Scottish Parliament Building, Edinburgh Wallsgrave Hospital, Coventry Bath Street, London Healthy Living Centre, Derby Salmon Smokery, Bow Kew GardensRight: Intensive roofgarden over of both hard andsoft of the type of green roof system the waterproofing and insulationrequirements are broadly similar.

5 It isimportant to remember that the supportingstructure must be designed to resist theextra weight loading that a saturated greenroof will impose and the general principlescan be found in British Standard Code ofPractice BS 8217. The important factor is toensure that the chosen waterproofingmembranes are root resistant. Thewaterproofing and insulation specificationwill depend upon the requirement forthermal insulation; there are three choices:-No insulation WILOTEKT-PLUS typically used where green roofs arerequired over underground car parks, cutand cover tunnels roof ALPAFLORE with flat ortapered board insulation between the deckand the waterproofing, used where thethickness of the layers above the deck needsto be kept as thin as possible. However asthe waterproofing is above the insulation caremust be taken to protect the membranes frommaintenance tools insulated roof WILOTEKT-PLUS with the insulation on top of the insulation can be designed to resist theheaviest of loads and the waterproofing is wellprotected from the effects of s ALPAFLORE and WILOTEKT-PLUS waterproofing systems are perfectly adaptedto the needs of green roofs with particularresistance to impact, root action, fertilizersand and WILOTEKT-PLUS conform toall standards and have third partycertification.

6 They can be used under all forms ofinaccessible and accessible green roofs,including the use of hard surfaces on thefollowing substrates: concrete and masonry,timber and timber derivatives, profiled metal. ALPAFLORE is normally installed as a two-layer system in its own right or as a singlelayer protection onto asphalt or over liquid-applied waterproofing systems. WILOTEKT-PLUS is ideal for use on inverted and on non-insulated can also be used to protectunderground works such as actively encourages the principles ofvalue engineering through designto ensurebest value is achieved by our clients. Throughearly design and specification participation inprojects Axter guarantees delivery of costeffective solutions to meet the most onerous ofdesign briefs and budgets thus eliminating thenecessity for expensive and time consumingvalue engineering exercises later on in thedevelopment MANAGEMENTW ater management is determined by whetherthe green roof is to be intensive or some cases a hybrid system between thetwo may be required.

7 A high proportion ofrainwater that falls on landscaped roofs isretained by the soil/reservoir system thusreducing the strain on the surface waterdrainage system. Roofs can be constructeddown to zero degree slope but provisionshould be made for internal or externalgutters, roof outlets and overflow designFor extensiveroofs, where the soilthickness is a minimum, water needs to beretained and therefore a specialist reservoirboard, BAC CANALIS, is used below thegrowing medium. On slopes it is necessaryto provide a barrier to resist slippage. TheHYDROPACK trays incorporate a intensivesystems the growing mediumnormally holds moisture sufficient for plantneeds, although irrigation is oftenincorporated into the design, and drainagemust be provided to allow storm water toquickly drain. Axter provides a specialistdrainage board, Axter DRAIN, which,whilst strong enough to withstand imposedloads, allows water to drain away freely.

8 HARD AND SOFT LANDSCAPINGAs with all landscape gardening theopportunities are limitless. Axter works witha number of experts in their field who aimto achieve your goals. These experts willgive planting and hard standing advicebased on the building s position, rooforientation, height of the roof above theground, roof pitch, weight limitations,preferred planting, componentsustainability, maintenance levels andperformance required from the plant andhard standing extensive green roofVERNIS ANTAC primerVAP AL SK insulationHYRANGER SPOT S3V base layerALPAFLORE PY AR top layerBAC CANALIS reservoir boardAXTER filter layerGrowing medium and plantsDesign flexibilityto create outstandinggreen roofsDesign RequirementsListed below are some of the items thatneed to be considered when designing agreen roof . Further information can befound in the ALPAFLORE Avis TechniqueNo.

9 5/02-1595 and the WILOTEKT-PLUSETA No. ETA-03 in all flat roofs the waterproofingshould be taken up at least 150 mmabove the finished surface be it soil,paving, gravel etc. It is advisable to havea plant free area immediately adjacent toupstands,this can be achieved by infillingwith gravel instead. roof penetrationsIdeally roof penetrations, pipes, extract vents, air conditioning units, etc.,should be concentrated in one area. This simplifies the waterproofing detailsand gives greater unbroken space for roofs with deep soil and whichare regularly irrigated are accepted as fire roofs are accepted as fireresistant so long as basic rules arefollowed. These include the depth andtype of soil, provision for horizontalfirebreaks, gravel strips aroundpenetrations, etc. Axter can give advicefor any particular roof roofs used as amenity areas arelikely to have sufficiently high parapets tomake supplementary safety provisionWith Axter s ALPAFLORE and WILOTEKT-PLUS systems there is virtually no limit to green roof design, beit over commercial, industrial or domestic buildings, cut and cover tunnels or buried earth (underground)structures.

10 Most landscape designs possible on the ground can be achieved on the roof so long as thesupporting structure is designed to take the load. This could be a formal garden with planted and pavedareas, an extensive roof with a wide range of rockery plants or even a replication of the uniqueenvironmental aspects of a brown field has the expertise to turn your dreams into reality, call today for a detailed intensive green roofWILOTEKT primerConcrete structural deckWILOTEKT flow control layerWILOTEKT rubberised bitumen compoundWILOTEKT polymer bitumen membraneAXTER XPS insulationAXTER DRAINA xter filter layerGrowing mediumIntensive plantingAxter can provide a full maintenanceschedule designed for the specific needs ofeach roof . Mowing of grassed areas, removalof unwanted plants, re-planting, irrigation,fertilising, providing additional material all be required from time to time tomaintain the roof in a good vegetative state.