b'BUILDING CODEVegetated roof systems are also vulnerable to specified wind loads.thishappens,considermodifyingthe roofdesignbyincreasingparapet height. Parapets induce enough turbu-lence at roof corners and edge zones to diminish wind uplift loads; as parapet heightincreases,loadsdecrease.The NRCwebtool,Wind-RCI,includes parapet height as one of several design parameters the user selects before gener-ating a report (the Wind-RCI threshold height for parapets is one metre). If you want to see what effect a taller parapet has on wind uplift loads, use the NRC web tool to produce a calculated load report for a given roof, both with and without tall parapets.You can also select a different method ofsecurementwhenSWLsexceed the DURs available in tested assembly reports for your preferred system. For example,someofthehighestDURs are available in AARS tested assemblies. While it may cost more to build a roof withadhesives(becauseeachlayerof material must be individually adhered), the added cost may offset more expen-siveoptions,suchasaddingparapet height.Expecttomaketrade-offsin roofdesigntofinalizeadesignthat conforms to the Code.Finally, consider a hybrid securement approach to roof assembly design. If you are designing a conventionally insulated assemblywithanexposedmembrane (no overburden or roof covering), and the available assembly tests do not offer DURs that are high enough to exceed the calculated SWLs, consider engaging a registered professional skilled in the work of Division B, Part 4 to help you evaluatethebenefitsandliabilitiesof www.rcabc.org l31'