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Showing results for tags 'green roof'.
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Hi, I’m installing a sedum roof onto a 20 sq m garden room GRP flat roof. A common system seems to be: drainage layer on the bottom, then substrate, then sedum roll on top. But some companies sell a lightweight substrate roll e.g. https://thegreenroofcompany.co.uk/product/sempergreen-lightweight-system/ while others use a loose growing medium e.g. https://www.sedumsupply.co.uk/green-roof/growing-mediums/ instead. Is either one better? And I’m concerned about the weight if using a loose growing medium. My calculations are: Joists - 21.5cm deep x 5cm width 40cm between joists centre to centre span 4m (front to back of garden room) https://www.timberbeamcalculator.co.uk/en-gb/span-table/floor-joists?load=1.5&class=C24 says with up to 1.25 kN/sq m, ie 127 Kg / sq m weight, joists can be 4.414m long Total weight per sq m: Sedum roll 400kg (I bought it, that’s what it weighs!) / 20 sq m = 20 Kg / sq m Growing medium (recommended 1.5 - 2 bags / sq m) say 1.5 of the 25Kg bags: 37.5 Kg / sq m or when wet multiply by 1.5? So 56 Kg / sq m GRP 14 Kg / sq m Plywood 4 Kg / sq m TOTAL: 94 Kg / sq m So it is under the 127 Kg / sq m maximum, so should be OK? Can anyone check this and say if they agree?
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Hi, I am about to have an extension onto the side of my house with a flat roof – it’s about 30 square meters. The current plan is for a zinc roof, however we are thinking about the possibility of a grass/living roof. I was wondering what the pros and cons are for doing this? Is it relatively simple to do? Is it that difficult to maintain or is it just some decent effort that is needed? Does it cost a lot more than a zinc roof? And is this something a traditional roofer will do or is this a specialist trade? Of course I have googled all of these but I’m sure this site will have the real answers !!!
