Changes

The green roof media used in Ontario can be classed according to proportion of composted biological material. Some existing installations  use materials which comply with FLL guidelines, whilst others use a much higher proportion of [[compost]].[http://grit.daniels.utoronto.ca/wp-content/uploads/2016/06/Comparisons-of-extensive-green-roof-media-in-Southern-Ontario.pdf]

The green roof media used in Ontario can be classed according to proportion of composted biological material. Some existing installations  use materials which comply with FLL guidelines, whilst others use a much higher proportion of [[compost]].[http://grit.daniels.utoronto.ca/wp-content/uploads/2016/06/Comparisons-of-extensive-green-roof-media-in-Southern-Ontario.pdf]

In many proprietary systems the default option for planting medium will be a granular material with very low organic matter content. However, many companies can arrange for a high organic content alternative to be substituted if requested.   

In many proprietary systems the default option for planting medium will be a granular material with very low organic matter content. However, many companies can arrange for a high [[organic matter]] alternative to be substituted if requested.   

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|+ Considerations for using a 'high organic' planting medium

|+ Considerations for using a 'high organic' planting medium

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!style="background: darkcyan; color: white"|Benefits

!Benefits

!style="background: darkcyan; color: white"|Disadvantages

!Disadvantages

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Increasing the depth of planting medium from 10 cm to 15 cm has been shown to benefit the vegetation<ref>MacIvor JS, Margolis L, Puncher CL, Carver Matthews BJ. Decoupling factors affecting plant diversity and cover on extensive green roofs. J Environ Manage. 2013;130:297-305. doi:10.1016/j.jenvman.2013.09.014.</ref>; stormwater retention was not improved with this increase in depth <ref>Hill J, Drake J, Sleep B, Margolis L. Influences of Four Extensive Green Roof Design Variables on Stormwater Hydrology. J Hydrol Eng. 2017;22(8):4017019. doi:10.1061/(ASCE)HE.1943-5584.0001534.</ref>.

Increasing the depth of planting medium from 10 cm to 15 cm has been shown to benefit the vegetation <ref>MacIvor JS, Margolis L, Puncher CL, Carver Matthews BJ. Decoupling factors affecting plant diversity and cover on extensive green roofs. J Environ Manage. 2013;130:297-305. doi:10.1016/j.jenvman.2013.09.014.</ref>; stormwater retention was not improved with this increase in depth <ref name =Hill/>

 

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