I want to redo the cracked rendering around my dormer window. I want to use stirling board with expanded metal pinned on and then cement rendering on top of this. When I remove the old rendering it will leave me looking at the wodden lathes that it was attached to. Do I remove all the old wooden lathes and than fix the sterling board on the studwork or is there a membrane between the studwork and the board. Also does the expanded metal fix directly onto the board or is there batons first and then the expanded metal fixed to these. I am not sure if I have to have a gap between the metal and the board!!