You need to educate me Rich :RpS_thumbup:
it would be my pleasure to educate/bore you further on the subject.
the days of using eml and sand cement etc over timber frame are over, renders have moved on a lot with carrier boards etc.
you can use a scratch render over a carrier board but it needs to be a mineral render, standard mono is to heavy, they look the same as mono on completion but have a different composition ie a lot more lime in etc.
the last wet dash we did was a parex system, it was on a gtec aqua board.in laymans this is similar to a plasterboard and it handles the same cut the same, but is fit for outside use and is fully waterproof. the jury is still out on wether gypsum boards are suitable at all, would I use them on my house mmmm..... not sure, but its a warranted system with a full BBA. there are various decent other boards about such as mr lords aqua board or now that siniat have taken over Lafarge they have relaunced the purple board which is a great improvement on the orange gtec board, so you take your pick.
we applied a base coat of maitie [this is an adhesive, there are other manufactorers adhesives such as Enewalls PACC adhesive or Marmorits sm700, all good gear] standard colour g00 which is a chalk colour because we were using a white spar with a 355 mesh [5mm mesh not like mono where we tend to use 10mm]keyed not spated flat, left it to dry, then a top coat of the white spar mixed in with the maite again [colour g00] and applied it the wall, and it looks the dogs nuts,
I issued all the signed warranty on completion for the whole system, client received the signed warranty so they were happy, so then the architect was happy, that meaning the contractor was happy, I was paid so I was happy.