I have been doing a bit of planning on the rendered section of our new build. Its a twin wall MBC build.  About half the build will be clad with render board and thin coat render. What i cannot find is how to deal with cavity trays above the windows and doors and also at a roof abutment     The above is from the Knauf detail and it does not show any form of a tray. Another manufacture has a metal channel above the window that drains to one side. I think @JSHarr