Hey folks, I'm renovating our new house and just removed the architrave around a door to access the cracks behind. The plasterwork was just resting in place and fell out at the first touch. See the photos for a better idea. How do I repair this to make sure that it doesn't happen again? I'm thinking SBR, sand & cement followed by a plaster finish (I'm plastering the wall anyway). Will that SBR allow the render to bond to the wood frame? Thoughts, please? Many thanks in advance.