How do I repair crumbling cement render?

Sassa

How do I best repair this section of what I assume to be concrete or cement render? Someone trying to drill into it caused it to crack, one of the lower pieces looks quite loose. Shall I remove it and build the area up somehow? What products would be best to use?

There’s also something strange happening on the other side of the window, see second pic.

EricL

Hello @Sassa 

Welcome to the Bunnings Workshop community. It's sensational to have you join us and thanks for sharing your question about repairing your cement render.

I suggest removing your roller blinds temporarily so that you can access the damaged section of the render. Remove all the loose pieces and the green wall plug that is no longer needed, next follow the steps in this guide - How to repair a rendered wall by @Nailbag. Regarding the broken section inside your house near the window, I suspect that the person doing the drilling passed through the wall and overextended reaching past your window. If the render inside is loose and can be removed, I suggest taking it off and patching it as well.  

If you have any other questions we can help with, please let us know.

Eric