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Growing green aspirations


or growing numers o seluilders, green roos are the right choice or topping o a home ut what are the key practicalities that you need to consider  and are they suitale or all proects Julian Thurbin of Wallbarn has the answers


WHY INSTALL A GREEN ROOF? Many self-builders love the individualism, loo, and ecoenefits o green roos s well as eing an increasingly vital haitat for insects and birds, they have many positive environmental impacts, including managing heavy rainall y prolonging the time etween rain alling and enter- ing the drainage system, improving air uality, reducing the ran Heat sland eect in towns and cities and oering sound and thermal insulation enefits


WHAT ARE THE BASICS TO


CONSIDER? There are two primary considerations – is your roof pitch suitable, and can your


home or the uilding taing the green roo, or eample an etension, garden room or leisure suite support its weight n terms o roo pitch, most green roos


are installed on at roos generally a maimum pitch o around , allowing the use of a traditional ‘roll-out’ system or newer modular approach hat said, they can be installed on more complex projects (for example convex roofs) or pitches of more than 15°, but this does generally limit system choice to rollout only


hen it comesto load earing reuire- ments, a structural engineer should e consulted to ensure the structure can support the weight o a green roo, which may weigh up to  gm2


when satu-


rated or newuild proects or eten- sions, the reuired structural integrity can e designedin


Once you’ve established viability, the net decision is choosing etween a rollout green roo system and a modular solution


ROLL-OUT VS MODULAR – WHAT’S


THE DIFFERENCE? ntil a ew years ago, rollout or carpet systems) were the established method for laying a green roo his approach entails installing each element individually  drainage layer, root arrier, sustrate and sedum plants or large roos, or those with dierent depths or a pitch higher than around 15°, this traditional method remains popular Modular systems are a newer development, comining all elements o a green roo, including plants, in pre-prepared trays or cassettes that lock together during installation hey are essentially an estalished green roo in a o, delivering an instant result uicly and cleanly, and removing potential or error hey also allow access to the roo dec post installation  y liting out trays as required, which can then be returned into position


CAN I DESIGN AS WELL AS INSTALL


A GREEN ROOF? odular green roos lend themselves to design and installation y competent self-builders, and system manufacturers should be able to assist with questions and provide technical support he asic uildup is a geotetile aric laid onto the waterproofed roof, followed by the green roo cassettes which are cliced into place on top assettes can e cut to fit the space precisely and roo edges finished with aluminium edging and pe- ling see elow paragraphs  a rollout solution has een chosen wed advise engaging specialists to carry out the wor rom specification to installation


ARE THERE ANY TECHNICAL ISSUES


TO CONSIDER? ire regulations reuire a hard order e- tween vegetation and walls, and around eatures such as rooights or all green roos his is oten achieved using an aesthetically pleasing pele order he fire perormance o green roos is also eing discussed more reuently leading manuacturers to oer systems with industry fire classification  oo    rom physical independent


6 www.sbhonline.co.uk mar/apr 2022


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